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Home > Home Wiring USA Archive: NEC 1999 > Main Dwelling Design and Options > Wiring a Dwelling (NEC 1999)

Common Wiring Methods Used Concerning Wiring a Dwelling (NEC 1999)

By Warren Goodrich
Common Wiring Methods Used Concerning Wiring a Dwelling (NEC 1999)

MARKING THE RECEPTACLES FOR BOX PLACEMENT

Upon entering your home, and in preparation of wiring your structure you should first mark out your switches and receptacle placement that you desire and that is required to meet the minimum safety standards of the NEC. This section is for marking the receptacles in living areas. Take a tape measure, with a friend, and measure from the end of a wall to 6' along the wall, from an opening [doorway] and then measure 12' from that receptacle to the next receptacle as long as that wall is unbroken by an opening [doorway] in the wall. 210/52/A/1

Now continue measuring until you have reached the end of that unbroken wall. You must make sure that the last receptacle marked, is within 6'; of the end of that unbroken wall. As you measure, the required distances, you should mark, with an ink pen, on the stud, and at eye level with an “R”, for reference only, not height. This “R” marking will represent the need for a receptacle at that point, but will not represent the height that you will mark later with a measuring stick. Watch out for any obstructions such as windows going down to the floor, or doors, or cold air ducts, or a bad place to get a wire to that position, as you mark for receptacles [you may wire crossways only {perpendicular} but not long ways {parallel} through a cold air duct]. 300/22/C/Exception You must not place a receptacle or switch in a cold or hot air duct.

If you hit an obstruction [examples are a doorway, window installed ceiling to floor, or built in cabinet] back up to the nearest convenient position on the wall that a receptacle can be easily mounted. You must then measure 6' [from the other side of the obstruction or break in the wall the same as it was a new wall] to the next receptacle that is required, and repeat this process until you reach another door, or the end of the wall. Keep in mind that what you are doing is setting these receptacles so that you will not be beyond the maximum Code distances allowed, between the end of the wall [6'] and between each receptacle [12'], in the living areas. Living areas are as listed but not limited to, a living room, a bedroom, a dining room, the kitchen area that is not over a counter area, a den, a residential office, a play room, an enclosed sun room, etc. 210/52/A Remember that a garage, a laundry, a utility room, a hallway, a closet, or a foyer are not considered living areas and are not required to be included in the 6' / 12' rule. In these nonliving areas receptacles are installed in an as needed bases.

The Code requires that no wall [ in a living area ], over 2'; long, can be without a receptacle. 210/52/A [with the exception of behind a door or in a non-living area such as a hallway], and any wall must have a receptacle within 6’ of the end of the wall [including doorways, to be considered as an end of the wall], and the distance being no more than 12' between any two receptacles along an unbroken wall. Remember that in areas such as lofts, that have a long railing, half walls, etc. has the same requirements as a full size wall. 210/52/2/C These type walls may be served with a surface mounted receptacle mounted on a post or an approved floor receptacle as long as the floor receptacle is located within 18” of the wall or railing. 210/52/3 Each receptacle will serve 6' each direction from itself. Two receptacles 12' apart will serve 6' each, towards each other, fulfilling the 12' allowance to be covered by both receptacles. Rooms such as garages, laundries, utility rooms, etc. are exempt from the 6'/12' rule. These non living area style rooms are considered work areas and not living areas. 210/52/A through H

The 6'/12' rule is intended for the wiring design of receptacles along all walls within the living areas to be within 6' of any lamp, television, radio, etc. You should find that all apparatuses designed for living areas that you may buy will have a 6' cord. [designed for a light duty and low amp usage] You should also find that all small appliances designed for the cooking areas [small appliance branch circuits] that you may buy will have a 2' cord. [designed for a heavy duty higher amp usage] Now you should be able to see the intent of the master designs in the whole picture for safety, as per the NEC minimum safety standards.

ATTENTION ; RECEPTACLES ARE ADVISED NOT TO BE OVER BASEBOARD HEATERS. [424/9 FPN NOTE]

MARKING OUT THE HOUSE, SET UP FOR MARKING BOX PLACEMENT

Next in preparation to wiring your structure, you should nail on one example of the following boxes, to set up a measuring stick for production purposes. I would nail these example boxes onto the wall at the height suggested, [“as accepted practice”, {Code mute on height of receptacles and switches} ]. A switch box 48” [in the living areas], a receptacle box 12” [in a living area], a receptacle box, or switch box, to be used over a counter 42” [in a kitchen counter area], a washer, or dryer receptacle box 36” [in a laundry area, to be installed behind an appliance]. These suggested heights are designed to be measured at the bottom of the box, from the floor to the box. All of these example boxes should be at the height that you prefer, just stay uniform with other boxes, of the same usage design. The above suggested heights can be changed to meet your desires, just stay uniform to avoid a roller coaster look on the finished product. A ¼” variation shows up on the finished product and then you would get to look at that misplaced receptacle or switch for the life of the structure.

In the past, some electricians used the following as a personal rule; hammer height, chest height, eye level, etc. These are not normally accurate, and will usually show uneven boxes, throughout the structure, for the finished product.

I suggest that you make a measuring stick using the above mentioned example boxes in order to set up this measuring stick for use in measuring the rest of your dwelling. Material such as a 2 X 2 board or even smaller in diameter about six feet tall should work fine as a measuring stick. Set the new measuring stick next to the first example box that you nailed on. Be sure to set the stick on the bottom plate of the wall, not the sub-floor. The sub–floor may not be level, and this sub floor may change, as you move through the dwelling, thus, changing the height of the boxes. The change in height can happen, without you noticing the uneven boxes, until it is too late! While making the stick, mark a line on the measuring stick with a fine line pen or pencil for accuracy, so that it is even with the top of the example box that you just nailed up. Write above that line, on your measuring stick, identifying the intended usage of that box that the line represents with an R for a receptacle, or an S for a switch, or a T for a thermostat, etc. The reason for marking the top of the box on the measuring stick and onto the stud where a box is to be nailed is so that the line set that you marked is more easily seen while nailing on the boxes. Now proceed to mark the measuring stick with the height of the rest of the sample boxes that you nailed on previously.

You have now made a measuring stick to mark the box heights for the rest of the boxes to be installed throughout the remainder of your dwelling. You will refer to these markings after you mark the studs throughout your dwelling, reminding you as to where, and how high each box is designed to be installed, and their designed usage, later in your wiring procedures.

SETTING BOXES IN THE KITCHEN

The kitchen is special pertaining to the maximum allowed distances between counter receptacles. They are as follows; The sink, refrigerator, oven, and cooking range will break the counter creating a new [end of counter], the same as a doorway in the living area. 210/52/C To start marking your counter receptacles you should measure from the end of the counter that you are going to start measuring and then measure along the counter to reach 24” and mark a receptacle. Then measure a distance of no more that 48” to the next receptacle, and continue marking the counter receptacles at a maximum distance between receptacles at 48” unless you reach a stove, refrigerator, oven, or sink that breaks the counter area. If you reach one of these mentioned appliances you must then start over with the 24”, because the appliance made a new end of the counter. Remember to look back to make sure that your last receptacle that you marked is within 24” of the end of the counter that you just encountered. Now look for any counter space that is less than 24” but more than 12” and also mark a receptacle over this counter space. 210-52-C-1 Each counter space wider than 12” must have a receptacle serving that counter area. 210/52/C/1

Next watch for a peninsula, or island.

The peninsula or island must have a receptacle serving any and all counter space that has a short dimension {width} of 12” or greater and a long dimension {length} of 24” or greater. 210/52/C

Peninsula counter spaces 210/52/C/3

If any peninsula is shorter than 24” inches from the connecting counter’s edge to end of counter {24” from the front of the adjoining counter to the end of the peninsula}, or if the peninsula is shorter than 12” in width from the front to rear or the counter, then a receptacle is not required to serve that peninsula.

Remember that both the width and the length of the peninsula counter space must exceed the minimum measurements before a receptacle is required

If the total length of the peninsula counter area is 24” or longer from the connecting counter’s edge, - and - if the peninsula is 12”, or wider, in width from the front to rear of the peninsula counter area , then at least one receptacle is required to serve the entire area of this peninsula counter space. If an appliance or sink breaks that counter area then you would have two counter areas, each area having to meet the minimum length of 24" and width of 12" before a receptacle must serve either counter area made by that appliance or sink that split that peninsula or island into two separately treated counter areas. Each side of that appliance or sink are considered stand alone counter areas. If either separated counter area is 24" long and 12" wide then a receptacle must serve that separated counter area. If that separated counter area does not meet both minimum length requirement of 24" long and 12" wide by itself then a receptacle does not have to serve that separated counter area.

Remember that both measurements [width and length ] must be more than the minimums before a receptacle is required to serve that counter space of the peninsula.

Remember that any peninsula counter space can be as wide or as long as it wants to be with only one receptacle required to serve that unbroken peninsula counter space

Island counter spaces 210/52/C/2

Island counters spaces are treated the same as the peninsula counter space except that they are measured from end to end instead of from any connecting counter’s edge.

Remember that any appliance installed in the island counter creates two island spaces that are treated, separately, as two islands. These separate islands must have their own measurement which exceeds the 12” width and 24” length minimums before a receptacle is required.

Remember that any island counter space can be as wide or as long as it wants to be with only one receptacle required to serve that unbroken island counter space

More rules of receptacle installation serving a counter space 210/52/C/5

A receptacle must be installed above the counter space but not over 18” above the counter space. No receptacle is allowed to be installed in a face up position in or on a countertop. Receptacles that are behind an appliance or otherwise made not readily accessible can not serve the counter space as a required counter receptacle. 210/52/C/5

If your counter space is flat and there is no place to install a receptacle over the counter, a receptacle may be installed below the counter area with intent to serve a counter top requirement but only if the counter top is flat with no back splash or walls connected to the counter top, and no cabinet within 18” above the counter that a receptacle may be mounted under that cabinet and within that 18” limit. This receptacle below the counter area can only serve as the required receptacle serving the counter area, if it is installed not more than 12” below the counter top surface and only if the counter top does not extend more than 6” beyond the supporting cabinet base. 210/52/C/5 Exc.

“Special Note” Many “AHJ’s” feel that there is an inherit danger when a receptacle is mounted in the wall of a base cabinet below the counter surface. If you would plug an electric skillet, etc. on the counter area into a receptacle mounted in the wall of the base cabinet there would be a danger to small children. This danger is felt to be present even if the receptacle is mounted below the counter and within the maximum distance of 12” from the counter top. A small child can play with that skillet, or other appliance., cord and pull this hot appliance, and its ingredients, down on his or her head which could cause a severe injury due to burning of their skin. I have drawn some alternative option examples that should meet the minimum safety standards set forth by the National Electrical Code. 210/52/C/5 Exc.

Examples of some alternative options for installing a receptacle serving as a required counter receptacle

 
 


It is my understanding that there is a plastic modular unit available that fits into floor or counter top, is expandable to include several utilities such as television – a convenience receptacle – telephone – computer cable - etc. These units are commonly used for a floor installation but I don’t believe them to be used exclusively as a floor unit. These expandable units are installed like a grommet installed in the counter top and are assembled and installed as a complete unit just snapped into a hole in the counter or floor area. The receptacles lay flush to the surface inside of the unit as individual pop ups, and are spring loaded. They are designed to be pushed down with your finger and it then pops up to an upright position for use. When you are done with using it you then just push it back down and it locks into the unit to remain flush with the counter until you want to use it again. You might want to talk to your supplier concerning this expandable receptacle subject.

Remember that the alternative option of mounting below the counter top is only allowed if the counter top is flat with no adjoining walls, and no method of installing a receptacle above the counter top is available, including mounting a receptacle in the bottom of the above cabinet if available and only if the receptacle can be mounted no more than 18” above the counter top. If none of the above options are available then you can mount below the counter top. 210/52/5/Exc.

Remember that if you mount below the counter top. The receptacle must be installed within 12” below the counter top and this receptacle can not be installed below the counter top when the counter’s edge extends more than 6” beyond its supporting base cabinet. An example of a counter being over 6” hanging over would be an attached breakfast bar counter area. 210/52/5/Exc.

Rules of other receptacle installation 210/52/5

Any receptacle in the kitchen, dining, or nook, that is not over the counters shall revert back to the 6’/12’ rule. 210/52AAt least one laundry receptacle is required for a single family dwelling. 210/52/F At least one receptacle is required in each attached garage. 210/52/5/G At least one receptacle is required in each unfinished basement in a single family dwelling. 210/52/GA laundry receptacle can not serve as these required receptacles. 210/52/GAny finished areas in a basement must be treated as a living area, the same as a normal part of a house. 210/52AThe finished area of a basement is a living area and must meet the 6’/12’ rule. 210/52A At least one receptacle is required in any hall with a wall containing 10’ of unbroken wall length, without passing through a doorway. 210/52/H An outside receptacle is required at grade level and not higher than 6 ½’ above grade both in the front and in the rear of a single family dwelling. 210/52/E A bathroom receptacle is required to be within 36” from the lavatory basin and must be installed on the wall adjacent to the basin. 210/52/5/D

Marking Switches

Switches are installed where they are desired, as long as the following minimums are met, as follows. At least one switch is required to be installed inside all habitable rooms at the point of entry of each room. A switch is required in each hallway. Switches are required to serve stairways at the top and bottom of stairs only if with six steps or more. In both attached and detached garages a switch must be mounted inside at the service door controlling a light both inside, and a switch controlling a light outside serving the stoop area of that service door [vehicular doors are exempt from a switch requirement to serve the vehicular doors]. An exception to the stoop light rule for a switch requirement is allowed to have the stoop light and switch to be omitted if an automatically switched area light such as a dusk to dawn light serves that stoop area. A switch is required at each attic or crawl within reach of the entrance, only if the attic or crawl is used for either storage or contains equipment, [the light fixture must be mounted near the storage area or the equipment area. ] A switch is required at all exterior doors to control exterior lights serving outside that entrance door. A switch is required at the entrance in each unfinished basement and utility room. 210/70

As you mark the receptacles for installation throughout the dwelling, also mark the switches, including three to eight way or more switch system designs, these switch systems are designed, as you may desire as long as the above minimums are met. There is no maximum number of how many switches that can control the same light. {multiple –switch system wiring methods will be explained later in this section} Be careful not to gang more than four switches in a single box combination without special consideration, as to obtaining switch covers needed on the finish product. Switch plates for more than four switches may not be available the way you might want them. You may mount two or more multiple ganged switch boxes mounted over the top of each other, if needed. {Be careful to leave enough room between the stacked boxes, for the cable entrances into those stacked boxes, as needed}. If you mount two boxes side by side, take extreme care to be exact as to the height. A ¼” off in height between the two boxes mounted within inches of each other would stand out like a sore thumb on the finished product.

I will try to explain the reasoning of some of the accepted practices. I want to state that this is only an opinion! If you put five qualified electricians together to do the same project you would have eight or more different opinions concerning different ways of doing that same project, and they could all be within the minimum Code requirements. This is why they call it the art of electricity.

The receptacle height, for the living areas could be placed at [hammer height, 12” to the bottom of the box, or even 12” to the top of the box, ETC.] There is no required height for any receptacle except as logic requires. Just be careful to make that height of your receptacle and switch boxes uniform, and accurate throughout the dwelling areas, for each use type of the receptacle. [counter, living, appliance type receptacles or switches] There is a maximum height for receptacle to serve the 6’/12’ rule of 5’6” high as a maximum. 210/52

Be careful as to your accuracy, because ½” difference in height of two adjacent receptacles in a given room will stand out like a sore thumb and be an eye sore to you throughout the life of the dwelling. I use 12” to the bottom for living type receptacles.

There is no height requirements for switches either. I use 48” to the bottom of switches. I place receptacles behind the refrigerator, and the washer at 36” to the bottom of the box. [easy to reach from over the appliance without standing on your head to unplug the receptacle] This 36” seems to hide the receptacle, and it keeps them within easy reach behind these appliances. Floor receptacles are legal, but they take a special installation requirement, and are normally expensive to install as the Code requires. {designed for the purpose and UL approved for use as a floor receptacle}370/27/B

It is my understanding that the reason for the 6’/12’ rule in the living areas, and the 2’/4’ rule over the kitchen counter areas are approximately as follows; The living areas are served by equipment, normally of light duty in amperage load, and are found with a 6’ cord length. The kitchen counter areas are served by equipment normally of heavy duty in amperage load, and with a 2’ maximum cord length. The goal is to eliminate the use of extension cords.

At least one wall switch controlled lighting outlet [switched receptacle or light fixture] shall be installed in every habitable room, bathrooms, attached garages, detached garages if with electrical power, all exterior door entrances, utility rooms, rooms or areas with equipment to be served, rooms or areas used for storage 210-70-A Switches are required at all attic and under floor areas that contain equipment to be serviced or used for storage. These switches are to be located at the entry to these areas and the light fixture must be in the area of the equipment or stored material. 210-70-A

Watch your height of switches on stairway landings. I put these switches at a midway point measuring 48” from the first step and from the landing floor height, then mount the switch box midway between these two measurements. This makes a fair comfort zone whether you are going upstairs and reach for the switch from the landing or going down the stairs and reach for the switch from the first step. Where there is more than 5 steps on a set of stairs, you must install a 3 way switch controlling a light for that set of stairs, located at the top and the bottom of the stairs. 210/70/A/2 There is an exception to the switch requirement, on a set of stairs entering a basement with no other outlet for personnel. This switch would be required at the point of entry which would be the top of the stairs. In this occasion a 3 way switch would not be required unless a bedroom, etc. is involved where you would stay in the basement living area. 210/70A/3

Watch the height of your receptacles over the side of your bathroom vanities. I put these at 42” at the bottom of the box from the sub floor, from the bottom of the box. Reasons for concern of this height is that sometimes there is a side splash on the vanities, and you will need the 42” height to clear these side splashes, which are the same height as the back splash of that counter. If you put these receptacles at 36” high over the vanity, you will be half covered by the back splash or if present the side splash. This also runs true over kitchen counters. In the kitchen, over the counters, I put both the switches and the receptacles at 42” from the bottom of the box, measuring from the sub floor to the bottom of that box. This allows for an even placement along the counters, upon the final product.

In the garage, I put the receptacles at 42” above the bottom of the wood bottom plate of the garage wall, and the switches at 48” above the bottom of the wood bottom plate of the garage wall. There is no minimum height in residential garages, but commercial garages require 18” minimum height from the finished floor to avoid any gas fumes accumulating in the garage. These gas fumes will lay low to the garage floor and you should consider this commercial minimum when deciding on your own home garage. This minimum is not a requirement but should make good sense even in a residential garage. The only reason you would want to push that 18” in my mind would be if you plan to remodel that garage into a living area at a later date where you would want lower placed receptacles.

Outside I put the receptacles above the grade of the yard, enough to be safe so that water is unlikely to reach the receptacle in severe flooding. The required outside receptacles may be placed above the inside floor level. This would be fine as long as you do not exceed the maximum height for outside receptacles of 6 ½’ 210/52/E

As you mark the devices, as you are required [6’ /12’{living areas}, or 2’ / 4’ {kitchen counter areas} rule], (and more , if you desire) You might consider measuring all of the rooms, with your buddy [ if you want ceiling lights in them] as to the width and length dimensions of these rooms, and divide these measurements by two, for one fixture, and three for two fixtures, etc., and mark these numeric figures on the door header of that room, for future use, in order to center the light fixtures at a later time, marking an arrow pointing up for the opposite wall demension, and an arrow pointing horizontally for the distance side to side of that room. This may speed your wiring effort in future procedures, for mounting light boxes, in the ceilings.

As you mark the switches on the wall, with your pen, then also mark what they are to be used for, below the “s” that you previously marked, representing a certain switch. Then if this switch is a three, or four or more way switch system, then mark the number of switches in this switch system, then subtract one from that total number of switches, and mark a little number under the corner of the “s” letting you know in the future that you designed this switch to work with that many other switches, in unison, to operate one light fixture [such as a stairway or hallways or entrances].

EXAMPLE OF MARKING YOUR SWITCHES

 
 


The switch system example, just above, tell us that we have a foyer on a single pole switch [reminding us that there are no other switches controlling that foyer fixture] A downstairs hall, with 2 switches on a 3 way switch system [reminding us that there is another switch somewhere in the dwelling controlling that downstairs hall fixture] A dining room with 3 switches, on a 4 way switch system [reminding us that there is two other switches somewhere in the dwelling controlling that dining room fixture] and an upstairs hall with 7 switches on an eight way switch system [reminding us that there are 6 more switches somewhere in the dwelling controlling that upstairs hall fixture]. This will help you when you start stringing the Romex needed to operate these specialty switch systems. [There is a two way switch system, but it is only used as a specialty switch system, to protect a gas pump, etc.] A two way switch system must have both switches in the on position in order for an appliance to run, creating a security type switch system. This is why you subtract one from the total actual number of switches so that you can know how large the particular switch system is you plan. [ A three way switch system is only two switches / A four way switch system is only three switches, etc.]

YOU HAVE NOW MARKED ALL THE RECEPTACLES AND SWITCHES REQUIRED, AND THAT YOU WANT, IN THE DWELLING.

NAILING ON THE BOXES

Now count the number of boxes, for each type, that you will need. Keep in consideration that you should not gang more than four switches, or two duplex receptacles in the same box, due to the lack of availability, of larger switch, and receptacle covers. You may stack multiple-gang boxes over each other, but leave space between them to provide the room needed for the cables entering the boxes. If you stack boxes, then split the 48” height in order to get these boxes stacked as evenly to the 48” mark as possible.

Now you have to decide on the type of boxes you want to use, the following are some of the pros and cons to the different type of boxes, as I have experienced using them.

Plastic versus steel, the steel box is a conductor of electricity. The plastic or fiber box is like the double insulated effect you get with the new type of electric tools we use daily. [less chance of the plastic causing a fire or shock hazard due to the conductivity of a steel box]. The steel box, some consider to be best, due to the durability of the steel construction. The steel has pre-cast threads allowing ease in inserting the screws on the finish, allowing a minimum of breakage when you miss the nail, and hit the steel, or the plastic box, with your hammer, while nailing on the boxes, versus a high probability of breakage with the fiber box, which seems to become brittle, in cold weather. The yoke screws of a device are harder to insert the screw, on the finish, when using plastic, or fiber boxes {not bad though}. The plastic box tends to be the toughest of all of these type of device boxes. As an experiment buy one of these blue plastic receptacle boxes and then try to rip, cut, burn, hit, or otherwise attempt to destroy, that plastic box without using heavy duty tools such as a blow torch. You may find this box to be quite a foe when trying to distort or tear or burn with a cigarette type lighter. The plastic box tends to be impervious to weather, moisture, and corrosion. The fiber box has the same double insulating effect as plastic, and has the same screw characteristics of the plastic, but is known to be brittle in cold weather. {You may experience breakage as you nail fiber boxes to the studs, in the winter} You must choose the type of box yourself. Each has the pros and cons. In my opinion the plastic or fiber are my favorites due to the properties of non-conductivity that they provide, as extra safety. Some say that the steel is strongest, therefore better. I feel that once you drywall, and bury the box, what is going to break it? Chances are once it is buried flush with the drywall, it will seldom, if ever be touched again.

Before you buy your boxes, consider the following; Paddle fans weighing less the 35 pounds require a special fan box approved for the purpose, or other mounting considerations. 370/27/C & 422/18 Paddle fans weighing 35 pounds or more must be supported independent from a box. 422/ 18 Fan boxes come in metal, or plastic boxes. Fan boxes can be found in any type of design such as a deep nail on type box, a shallow pancake type box, and a plastic or steel box that straddles the ceiling joist. You will find the steel fan box to have the tabs that normally have the threads for the 8/32 fixture mounting screws on a fan box will have the hole in the tabs enlarged expecting a long 8/32 screw to pass through that tab as a stabilizer and then threading into a threaded screw hole in the back of the box. When looking at the plastic fan box, you will normally find a threaded steel nut molded into the back of the plastic box.

The normal light boxes [not for use to install a fan] can come with a bracket to span between the joist spaces, or you can cut wood to span the joists, and then nail the box onto the wood nailer or header that you installed between the joists. Any light fixture box must be capable of supporting a fixture that exceeds 6 pounds but not more than 50 pounds, and with a maximum fixture diameter of 16”, 410/15/A I suggest the light box should have an 8/32 size screw [not receptacle style boxes with 6/32 size screws] to mount the fixture. The receptacle type box with the 6/32 screws can be utilized only if mounted in a wall or ceiling for the installation of a porcelain keyless or a porcelain pull chain weighing less than the 6 pounds. These porcelain type fixtures and the like weigh less, which would allow you to use the lighter duty boxes with the 6/32 screws found in receptacle style boxes. 410/15/A Take special consideration of any heavy fixtures, more than 50 pounds, requiring special mounting needs. This would include fixtures weighing over 50 pounds. The heavy fixtures shall be supported independently of the box, unless the box listed for use with that weight of fixture. 410/16/A

Are you using recessed tanks for lighting, if so, they need to be installed on the rough-in before drywall is installed, normally. Watch to get the proper recessed fixture designed for the purpose you are using it. Are you going to have a direct contact with the insulation, or are you using insulation chimneys instead, and accept the heat loss? Direct buried recessed light fixtures in direct contact with the insulation must be approved for direct contact with insulation or other combustible material, type “CT” recess tanks. Refer to the manufacturer’s recommendations printed inside the recessed fixtures. These no clearance approved or direct buried approved recessed fixtures usually have a recessed tank inside a recessed tank. Double insulation affect with an air space between the two light fixture tanks.

How many bathroom exhaust fans are you going to need? If you have a bathroom window that opens, then a fan is not required. If no window is present that opens, an exhaust fan will be required in that bathroom. This is a rule found in the CABO Building Code. If you are mounting the fan over a tub, or shower, you must have a fan approved for the purpose, and it must be protected by a GFCI control. 410/4/A and manufacturer’s recommendation.

Are you going to use closet lighting? If so, remember that you must meet the following clearances.

Incandescent lighting must be with a cover, or lens, and must meet the clearance measurements of two points as follows; 24” from the back and side walls, and 12” from any shelving [regardless of whether the shelving is there or not]. You must clear the total fixture including the bulb, globe, and fixture itself. 410/8/A & 410’8/D/1

Recessed incandescent fixtures and surface mounted fluorescent light fixtures must meet the clearance measurements of two points as follows; 18” from the back, and side walls, and 6” from the shelving [regardless of whether the shelving is present or not]. Remember that you must clear the total fixture including the edge of the trim for the fixture, not just the rough–in tank. You must also have a closed lens on these recessed tanks enclosing the incandescent bulb. 410/8/A & 410’8/D/1

You are allowed to mount a fixture on the header above the closet door if you like. Please keep in mind that if mounting a surface mount incandescent light fixture, this fixture must also have a closed lens containing the bulb, and a clearance of 6” must be maintained from that incandescent fixture and any adjoining walls due to the heat a bare bulb puts out, plus meet the 12” and 24” clearances of the back and side wall and the shelving.

If designing your wiring for a fluorescent fixture, you might consider drilling a hole at an angle from approximately 6” off center of the header side to side and then center up and down on the header. Drill this hole at an angle from the surface of the header to enter within the above stud or attic space. You may then run a Romex from the closet light switch through the attic and down through the hole you just drilled leaving a pigtail hanging out waiting for the finished product. After drywall has been installed and when you mount the florescent fixture on the header. You will find the ballast to be in the center of the florescent fixture and a knock out for a Romex connector and a wire about 6” off center of the florescent fixture. This knock out should now land over the wire that you previously installed. This type of installation is about the only way of meeting the minimum safety standards of the NEC, while installing a light fixture in a normal by–pass style shallow clothes closet. Upon your finished product of the structure, the wiring would be totally hidden, and the light would be illuminating what you are trying to see in the closet, because the fixture would be lighting directly over your head upon your entry into the closet.

Are you installing any of the following, even in your future plans? If so, they can be roughed-in now, with a minimum expense, and finished years later, saving you “mucho denero”; central vacuum, whole-house stereo, cable television, phones surround sound television, CAT 5 computer wiring, etc. The cost of the rough-ins may only be minor to rough-in now compared to a later installation, fishing the wires through closed wall as existing work.

When you buy materials the following may be a fair guess, as to what you might need, if you have a dwelling of around 2,000 square feet, with your designs at a minimum standard wiring design. The NEC requires that receptacles “only” in the kitchen, nook, dining, and pantry to be wired with 12 Ga. conductors. Accepted practice for wiring in a dwelling is to use non-metallic sheathed cable (may be known as Romex).

The rest of the dwelling may be wired in 14 Ga. conductors, with the exception of heavy use dedicated circuits such as water heaters, ranges, and the like. If you decide to use a mixture of 14 Ga. and 12 Ga., then I would guess that you would need about 1,000’ of 12/2wGrnd Romex, and 2,000’ of 14/2wGrnd Romex, and 250’ of 14/3wGrnd Romex. You might want to add 6/3wGrnd or 8/3wGrnd Romex as a minimum for the range, if electric, 10/2wGrnd Romex as a minimum for the water heater, if electric, 10/3wGrnd Romex as a minimum for the dryer, if electric, 14/2wGrnd Romex for the water pump feeder if used, 14/2wGrnd Romex for the gas furnace if used, 12/2wGrnd Romex for the washer, 12/2wGrnd Romex for the dishwasher, 14/2wGrnd Romex for the garbage disposal, if single circuit. The sump pump may be fed by a 14/2wGrnd Romex but is not exempted from the GFCI protection requirement unless direct connected. 210/8/4 Both the range and dryer must have an insulated neutral in its cable to meet minimum Code requirements. These two appliances use both 120 volt and 240 volt in their internal design, thus creating a need for a current carrying neutral. This conductor must be insulated. Both of these appliances must use a 4 prong receptacle, using a red, black, white and a bare/or green wire contained within that cable 250/134 & 250/138

Special Notes: REMEMBER THAT IF YOU INSTALL MORE THAN ONE MOTOR OR MOTOR WITH OTHER LOADS ON A CIRCUIT, WHETHER 14 Ga. or 12 Ga., IN A DWELLING, THEN ANY SINGLE MOTOR LOAD, BY ITSELF, ON THAT MULTI-MOTOR OR MULTI-USE TYPE CIRCUIT CAN NOT EXCEED 50% OF THAT CIRCUIT. 210/23/A

Special Notes: REMEMBER, ALSO, THAT ANY CIRCUIT, WHETHER 14 Ga. or 12 Ga., EVEN IN A DWELLING, THAT CONTAINS A SINGLE MOTOR LOAD ON THAT CIRCUIT WITH NO OTHER LOAD MUST NOT BE WITH A LOAD EXCEEDING 80% OF THE MAXIMUM RATING OF THAT CIRCUIT. THIS RULE APPLIES TO CIRCUITS WITH A SINGLE MOTOR LOAD, ONLY, ON THAT CIRCUIT. 210/23/A

ALL OTHER CIRCUITS, WITHOUT MOTOR LOADS MAY BE LOADED UP >TO 100% OF THE TOTAL AMP RATING OF THEIR CIRCUIT’S CONDUCTORS. 220/3/B/10

Special Notes: REMEMBER THAT YOU MAY USE A 14 Ga. 15 AMP, OR A 12 Ga. 20 AMP, RATED CIRCUIT TO FEED A SINGLE DEDICATED MOTOR CIRCUIT IF YOUR MOTOR WITH NO OTHER LOADS DO NOT EXCEED 80% OF THE TOTAL AMP RATING OF THAT CIRCUIT. 210/23/A

REMEMBER NOT TO VIOLATE THE FIRST SPECIAL NOTE IF MORE THAN ONE MOTOR OR ONE MOTOR AND OTHER LOADS ARE ON A CIRCUIT, THEN YOU MAY LOAD THAT CIRCUIT TO 100% BUT ANY MOTOR ON THAT CIRCUIT IS LIMITED TO A MAXIMUM SINGLE MOTOR LOAD NOT TO EXCEED 50% RATING OF THE AMPACITY OF THAT CIRCUIT.

REMEMBER A 14 Ga. 15 AMP RATED CIRCUIT IS EVEN ALLOWED IN THE KITCHEN, WITH THE EXCEPTION OF THE SMALL APPLIANCE BRANCH RECEPTACLE CIRCUITS

If you decide to use all 12 Ga. Wiring , then I would guess about 3000’ of 12/2wGrnd Ga. Romex, and 250’ of 12/3wGrnd Romex, and 6/3wGrnd or 8/3wGrnd Romex as a minimum size required for a range, if with electric range, 10/2wGrnd Romex as a minimum for the water heater, if electric, 10/3wGrnd Romex for the dryer, if electric, 12/2wGrnd Romex for the water pump feeder, if with water pump, 12/2wGrnd Romex to the furnace, if with a gas or oil furnace, 12/2wGrnd Romex for the following, a washer, a dishwasher, a garbage disposal. Wire sizing may be found for Romex in 310/15/B/2/A and 310/16 Please check obelisk note at bottom of page, concerning 14 or 12 or 10 Ga. or 6 Ga. Conductors, it will refer you to Article 240/3/D

Special Notes: YOU MAY USE EITHER 15 OR 20 AMP RECEPTACLES AND SWITCHES REGARDLESS WHETHER YOU USE 15 OR 20 AMP WIRE OR BREAKERS ON ALL OF YOUR CIRCUITS EXCEPT A SINGLE OUTLET ON A DEDICATED CIRCUIT. 210/21/B/2

The air conditioner equipment should be sized by the manufacturer’s name plate rating, and the conductor size is set by the name plate {minimum circuit ampacity}, as the load rating of the circuit for the air conditioner. The breaker may be sized by the name plate {maximum over-current} as the overcurrent [breaker or fuse] sizing, even though the breaker is larger than the conductor rating in ampacity. This is allowed because the overload of the air conditioner’s hermetic motor is allowed to protect the circuit conductor more accurately. 440/52. If you have question in this area refer to my pass out for HVAC and refrigeration name plate rating, for explanations, and code references. If the A/C has no 120 volt usage then this wire may be two conductor Romex with grounding conductor.

Any 220 volt appliances that use 120 volt in it’s design, even a single light bulb in that appliance, must have an insulated neutral {white}. All appliances must have an insulated neutral, if there is 120 volt being used within 220 volt appliances, such as a 120 volt clock, light, timer motor, etc. utilized within that 220 volt appliance 250/142/B and 250/134 and 250/138

STARTING THE ROUGH IN WIRING STAGE OF YOUR DWELLING

It was previously suggested that you make a measuring stick by marking the desired height line on that measuring stick with all the different uses of each type of electrical boxes to be mounted. It was also suggested that you use the example boxes that you should have previously nailed on. You should have made a fine line on that measuring stick at the top of each example box, previously nailed on as suggested heights [12”,48”,36”] throughout the dwelling, thus marking that measuring stick with each box usage height.

As we discussed previously, you should have marked each stud that needed a box with the usage of each needed box on that stud with an “R” or “S” throughout the structure. Now using this measuring stick, mark a fine line on each stud needing a box with the box height as needed in matching the box usage. Mark a line on each stud equal to the height representing the usage “R” or “S” that was previously marked. Mark this height line of the type of boxes needed on each stud, throughout the entire structure with its required height.

You are now in need of the electrical material required to wire the house as you desire and also meeting the minimums of the NEC. Once you have the material on the job site, then begin spreading the boxes throughout the dwelling, where they were previously marked for each usage type “R” or “S”. Just go around the structure, and pitch the right style box, as needed [single gang, double gang, triple gang, round light boxes, etc], towards the approximate areas, so that they will be within reach when you mount them to the structure.

Then mount the boxes as they were marked equal to the height and usage [single gang, double gang, triple gang boxes as needed]. Be careful to be exact matching the thin height line marked equal to the top edge of the box and even with the thin line marked for hieght. Precise installation is needed in mounting the boxes to avoid a roller coaster affect in the horizontal line of these boxes on the finished product. If the boxes are not exactly on the marked lines and a roller coaster affect happens, then these uneven boxes would stick out like a sore thumb upon the finished product.

Remember to hang the box out to the distance required but just short of the finished wall surface. A ¼” maximum gap is allowed, 370/20 between the wall surface, and the face of the box. Be careful not to stick the edge these boxes out beyond the finished surface, or you will have severe trouble in mounting the receptacle, and switch plates, flush to the finished walls. If you try to grind the box down in order to be flush again with the drywall, you will most likely remove the threads in the screw hole part of the box that your device’s mounting screws use. Be careful, also not to mount the boxes “angled to“ the surface of the finished wall due to the above mentioned reason. Remember, you previously set the measuring marks on the studs [height] for the top of the box for ease of mounting the boxes. Set the boxes for the switches, and receptacles, if using ½” drywall, just short of ½” out, straight and even with the drywall surface yet to be installed and even with the pre-marked height. If you are using bakelite boxes take care not to accidentally strike the box, they may shatter on impact. Once all the receptacles, and switch boxes are set, mount all of your light boxes holding them out in the same manner that you did the switch, and receptacle boxes equal to just short of the thickness of the drywall. Remember that you marked the center measurements of the room’s ceiling on the headers of the doors previously in order to speed this process. Now mount the exhaust fans, and recessed light fixtures at this time, remember to hold them out just short of the ½” required for the ½” drywall. 370/20

Special Notes” In the bathrooms, this is a small area, and if you are only 1” off center over the bathroom vanity with your light box, that box will stand out, and stare at you, upon the finished product as not being centered. Be exact here ! This exact accuracy is not as important in larger rooms, 1” either way in larger rooms is not normally noticeable on ceiling lights, in those larger rooms.

Once all the boxes, and recessed equipment have been mounted, then you are ready to start designing the wiring system. Designing the receptacle circuits take a special amount of calculations. I will try to explain how to do that calculation as follows;

REMEMBER;

All receptacles in a dwelling are general lighting type receptacles. This is true except those receptacles installed in a kitchen, nook, dining, pantry, or laundry and any appliance circuit that pulls more that 50 percent of the circuit feeding it power.

CALCULATE THE NUMBER OF GENERAL LIGHTING RECEPTACLES AS FOLLOWS

100% CAPACITY IN VOLT AMPS [WATTS] OF A 12 Ga. NONMETALLIC SHEATHED CABLE “ROMEX” EQUALS 2,400 VOLT AMPS [WATTS].

20 AMP MULTIPLIED BY 120 VOLTS = 2,400 Va @ 100%. ON A 20 AMP CIRCUIT

IF YOU ARE WIRING YOUR GENERAL LIGHTING TYPE RECEPTACLES WITH 12 GA., THEN DIVIDE THE TOTAL VOLT AMPS REQUIRED FOR GENERAL LIGHTING BY 2,400 VOLT AMPS [WATTS].

100% CAPACITY IN VOLT AMPS [WATTS] OF A 14 Ga. NONMETALLIC SHEATHED CABLE ”ROMEX” EQUALS 1,800 VOLT AMPS “WATTS”.

15 AMP MULTIPLIED BY 120 VOLTS = 1,800 Va @ 100%. ON A 20 AMP CIRCUIT

IF YOU ARE WIRING YOUR GENERAL LIGHTING TYPE RECEPTACLES WITH 14 GA., THEN DIVIDE THE TOTAL VOLT AMPS REQUIRED FOR GENERAL LIGHTING BY 1,800 VOLT AMPS [WATTS].

Measure the outside dimensions of your dwelling, not including the garage [ but be sure to include the finished part of a basement in your total square foot measurements]. Multiply the length times the width of each area that you measured, and add the total square feet area of each of these living areas together to make the total square footage of your living areas. That total gives you the total square feet of living space in your dwelling. Now multiply that answer times 3 volt amps. [ approximate watts ]. This total gives you the volt amps [approximate watts] that you will be required to provide for your general lighting receptacles and lighting fixtures. 220/3/A

Now divide that total volt amps required to serve the living areas of your dwelling by either 2,400 Va. if wired by 12 Ga. Romex, or 1,800 Va. if wired with 14 Ga. Romex. The answer you get from that division gives you the total number of general lighting branch circuits, the National Electrical Code requires you to have, serving your dwelling.210/11 and 220/3/B

Now add all of the general use receptacles [this is all receptacles not including dedicated circuits, and any receptacles in the kitchen, nook, dining room, pantry, or laundry].210/11/C

Now take the total number of general use receptacles, and divide that total by the number of general lighting branch circuits that you figured, as required. This will tell you the maximum number of general-use type receptacles that you may put on each general-lighting branch circuit. 210/11/B

AN EXPLANATION OF THIS TYPE OF CALCULATION REQUIRED TO FIND THE MAXIMUM NUMBER OF RECEPTACLES ALLOWED ON A CIRCUIT FOR GENERAL USE WOULD BE IF YOU PUT A RECEPTACLE ON EVERY STUD IN THE DWELLING, YOU MAY HAVE AS MANY AS 100 OR MORE RECEPTACLES PER GENERAL LIGHTING BRANCH CIRCUIT.

Special Notes” If you meet the 6’/12’ rule 210/52/A as a minimum in a bedroom, you might average around 5 or 6 receptacles per bedroom. Of those 5 or 6 receptacles you probably would only actually use 2 o3 receptacles. The average loads in the bedroom would probably be maybe a television, stereo, alarm clock, table lamps, etc. these are very light loads. The total receptacle load in the average bedroom would not normally be over maybe 4 amps.

Now let’s install a receptacle on every stud in that average bedroom we now might have 50 to 75 receptacles or more. How many receptacles would you use now ? Maybe the same 2 or 3 ?

This is why the NEC allows the calculations mentioned above as the method of calculation to find the receptacle circuitry design.

Those extra circuits you were planning on serving the bedrooms may be of better design usage if installed in the kitchen or laundry areas. These areas are where the heavy loads are normally found.

INSTALLING THE WIRING IN THE KITCHEN

The above type of wiring design method is not acceptable in the kitchen, nook, pantry, or dining rooms. These rooms have requirements “special to their own use” as I will explain in the following;

The kitchen, nook, pantry, and dining room receptacles must have 12 Ga. wiring. 210/11/C/1 All receptacles in the kitchen, nook, pantry, and dining rooms may be intermixed with each other, and are considered as the small appliance branch circuits. 210/52/B/1 Small appliance branch circuits include all general food use type receptacles in all of these food rooms, whether they are over a counter, or not 210/52/B/1 The refrigerator, or the devices that ignites of your gas range or cook top , or a clock receptacle may be installed on the small appliance branch circuits, without further load calculations. 210/52/B/1/exceptions No other outlets whether lighting, fixed appliances or anything in any other room may be installed on the same circuit with any receptacle located in the kitchen, nook, dining, or pantry. 210/52/2

You must have at least two small appliance branch circuits {serving the small appliance branch “use food type” receptacles}, available over the kitchen counters. 210/11/c/1 You may mix these small appliance branch “use food type” receptacles over the counter, with the small appliance branch “use food type” receptacles in the kitchen, nook, dining, and pantry that are not over the counters. 210/52/B/1

Keep in mind that the cook will probably not cook in the dining room, nook, or pantry, at the same time that they are cooking in the kitchen. This also, is expected to be the same scenario in the nook, dining, and pantry. 210/52/B/1 When they are serving in those rooms, they probably will not be using the receptacles in the kitchen, at the same time. The cook will most likely unplug the appliances in the kitchen and move them to the nook or dining room in order to make serving time more efficient.

The two small appliance branch circuits are left to the design of the electrician. Keep in mind that a cook will probably be cooking, centered tightly, in one certain area. I would like to advise that you might want to rotate these circuits in a wiring pattern such as every other receptacle on a different small appliance branch circuit. A example of this alternating style wiring would be the 1st, 3rd, 5th, 7th receptacle on circuit “A” and the 2nd, 4th, 6th, 8th receptacle on circuit “B”. This design would serve any tightly centered cooking arrangement centered over the kitchen counter with two separate small appliance branch circuits available, within reach, of the person cooking in one spot on the counter. This style of wiring of alternating receptacles on a circuit is not required by the Code, but should make good sense.. Remember that the NEC is the minimum safety standards required to be met. I doubt that I would want to wire my home just by the minimum, but that is your choice. You have to just meet the minimum safety standards set forth by the NEC. An example of wiring by the minimum safety standard which I would accept, but would not advise, are as follows. The Code implies that if you put all of the small appliance branch “use food type” receptacles in the kitchen, dining, nook, and pantry on one small appliance branch circuit, including the refrigerator and all of the receptacles over the kitchen counters, except one counter receptacle. Then if you put that one other receptacle over the kitchen counter on a second 20 amp circuit, creating the second 20 amp circuit as required, you would successfully meet the minimum safety standards. This style of designing the small appliance branch circuits would meet the minimum safety standard, but I would not advise this design.

THE FOLLOWING MUST NOT BE INSTALLED ON THE SMALL APPLIANCE BRANCH CIRCUITS;

Any fixed appliances, usually direct connected with a Romex connector, and / or any lighting, and / or anything in any other room, except the receptacles in the kitchen, nook, dining, and pantry as mentioned.

THE FOLLOWING ARE EXAMPLES NOT ALLOWED TO BE A PART OF THE SMALL APPLIANCE BRANCH CIRCUIT;

Dishwashers are not allowed to be installed on the small appliance branch circuits. Garbage disposals are not allowed to be installed on the small appliance branch circuits. Sink lights or any other type of lighting are not allowed to be installed on the small appliance branch circuits. The exhaust fan over the range is not allowed to be installed on the small appliance branch circuits. Any of the following; any permanently mounted appliances such as a trash compactor, microwave in a microwave cabinet, etc. are not allowed to be installed on the small appliance branch circuits. Remember that a small appliance branch circuit is any convenience receptacle, anywhere within a kitchen, nook, dining, or pantry. 210/52/B/1 Remember that you have a few exceptions allowed to be on the small appliance branch circuits and are as follows; the receptacle serving the devices that ignites range burners built into a gas range, a clock receptacle, and a refrigerator. 210/52/B/1 Remember that you can install a single circuit to serve the refrigerator, and dedicated as a refrigerator circuit, on a 15 amp dedicated circuit. 210/52/B/1/Exc.2

There is an exception allowing a switched receptacle from a general lighting circuit to be on a 15 amp circuit in the dining room. This receptacle is allowed to fulfill the requirement of a switch controlled lighting outlet, light fixture or switched receptacle, in the dining room. 210/70/A/1 and 210/52/B/1/Exc.1 This 15 amp receptacle used as a switched receptacle does not fulfill the requirements of the 6’/12’ rule requirement for the small appliance branch circuit in the dining room. 210/52/A A small appliance branch circuit must not be switched. 210/70/A/1

WE WILL NOW TALK ABOUT THE DEDICATED CIRCUITS.

Your garbage disposal pulls approximately 9.8 amps, and may be installed on a 15 amp rated circuit with other loads or as a dedicated circuit, even if found in a kitchen. This is true with this motorized fixed appliance, or any other motorized fixed appliance, even though it is found in the kitchen, or bathroom, or laundry, or anywhere else in the dwelling, as long as this motor type circuit does not include any small appliance branch circuit receptacles, laundry receptacles, or a dedicated bathroom receptacles circuit serving all the bathrooms. 210/23/A/ Exc. and 210/11/1,2&3 These same 15 amp rated circuits may possibly be on a circuit with other loads, such as lighting, just so long as they are not a small appliance branch circuit receptacle 210/23/A/ Exc. and 210/11/1,2,&3, and not the laundry receptacles, 210/23/A/ Exc. and 210/11/1,2,&3 and not dedicated bath receptacles circuit serving all of the bathrooms. 210/23/A/ Exc. and 210/11/1,2,&3 You can put any fixed appliance containing a motor on a 15 or 20 amp rated circuit with no other loads as long as this fixed appliance does not exceed a load of 80% of that 15 or 20 amp rated circuit, 210/23/A and 384/16/D and the conductor is rated at least 125% of the full load amps of the appliance. 430/22 You can put any fixed appliance containing a motor on a 15 or 20 amp rated circuit with other loads, on the same circuit as long as any one motor installed on that circuit does not exceed 50% of the total rated load of the circuit. 210/23/A

An example of motors and other loads could be as follows. You could install the range hood, or any other motorized appliance, on a general lighting branch circuit from a living room or bedroom, such as receptacles or lights in these habitable rooms, as long as that motor did not exceed the 50% maximum motorized appliance load for any one motor on that circuit, and did not mix receptacles in the kitchen, dining, pantry, laundry, or bathrooms, on the same circuit.

Your dishwasher pulls approximately 17 amps, and must be a dedicated circuit on a 20 amp rated circuit, because it exceeds the 50% maximum load of a motor on a circuit designed to be with other loads on that same circuit. 210/23/A There is a rule that allows the “Authority having Jurisdiction”, your Inspector to role two motors such as a garbage disposal and that dishwasher to be on the same circuit. It is called a non-coincidental load rule. This rule allows your Inspector to allow special consideration to a specialty circuit. I allow the garbage disposal and the dishwasher to be on the same circuit because the garbage disposal would not usually run long enough to affect the overcurrent device protecting that circuit. I feel that a garbage disposal would only normally run approximately 30 seconds. This would almost not be noticed at all. Please check with your “Authority having Jurisdiction” before utilizing this non-coincidental load rule. 220/21 and 430/24/Exception 1 and 430/22/B

Remember that a 10 Ga. conductor can be loaded to a maximum of 30 amps, a 12 Ga. conductor can be loaded to a maximum of 20 amps, a 14 Ga. conductor can be loaded to a maximum of 15 amps. 240/3/D The loading of the circuits in a dwelling may be rated at 100% for everything 220/3 but motor loads which are rated at 80%. 210/23/A or 50% load of any one motor on circuits with motors and other loads 210/23/A The “if specifically otherwise permitted” statement in the NEC refers to motors only. 240/3/E,F,&G If you are serving a motor, then you may use the chart in 310/16 allowing 20 amps on 14 Ga., 25 amps on 12 Ga. and 30 amps on 10 Ga. This is true with motors regardless of the temperature rating of the insulation of the conductor due to the terminal limitations of 60 degrees centigrade of the terminals used in the circuits, unless the conductor is rated over 100 amps. 110/14/C/1 If the conductor is rated over 100 amps then you may use the 75 degrees centigrade column because of the 75 degree rating of the larger 100 amp rated terminals. 110/14/C/1

WE WILL NOW TALK ABOUT THE AFFECT OF VOLTAGE DROP

Remember, as a rule of thumb; Do not go over approximately 125’ of wire without considering a voltage drop for 120 volt circuits, and approximately 250’ of wire on 240 volt circuits throughout the property. Now in order for you to meet the minimum safety standards set by the Code, you shouldn’t have to worry about voltage drops of general lighting circuits and / or several receptacles on a circuit that are inside a dwelling. This is due to the inherent design requirements of the NEC concerning dwellings and their detailed loading design requirements of the NEC as a minimum wiring design. It may however, be to your advantage in regard to your future Utility bills, whether inside your dwelling or outside your dwelling, to consider voltage drop on certain circuits. You might want to consider voltage drop affects for any of your automatically operated or continuous usage equipment throughout your property concerning your wiring designs.

Voltage drop is a controversial minimum requirement in the NEC. It is generally accepted that voltage drop requirements are “advisory only” with the exception of the following requirement. You must increase the grounding conductor where the branch or feeder conductor is increased in size due to a voltage drop that is present in a circuit. 210/19/Exc. 4 250/122/B

I feel that we should interpret the NEC as if it allows for no voltage drop. 210/19 The way that I feel is that we should interpret the NEC by reading this section as if the conductor must be capable of carrying the load. This should be interpreted as no voltage drop allowed, at all. The FPN note could then be used as an allowance in your wiring design that can be approved by allowing the 5% voltage drop. The FPN Note which is advisory in Indiana will advise for a limited allowance of 5% on a branch or on a feeder or a total combined voltage drop of 5% for both the feeder and branch combined.

Where voltage drop is calculated, voltage drop must be calculated from the serving transformer to the end of line of a feeder or branch conductor or both combined, whichever section that you are calculating. I guess the decision is up to you, as to whether you should worry about voltage drop or not. As long as you stay within the 5% suggested in the FPN note then I feel you should be all right. I feel that anything over the 5% should be addressed. Just keep in mind that voltage drop is electricity that we pay for, but do not get to use.

Also consider that the higher the voltage drop equals the lower the voltage available to run your equipment. If the voltage is less than the equipment is designed as needed for the equipment to run, then the amps needed to run the equipment will increase. The lower the voltage the higher the amps. The higher the amps the higher the heat of the equipment. The life expectancy of the equipment will decrease equal to the lower the voltage. This lower voltage will cost you more money to run your equipment, and the lower voltage causes excessive heat which can damage your equipment and shorten the life or your equipment.

An example of the affect of voltage drop on your pocket book would be the following. If you have a 125 volt ½ horse power rated motor designed to operate with a full load amps of 9.8 amps 430/148, and if you had a voltage drop of 20%. This wiring design would equal 100 volts available to serve the motor designed to run on 125 volts, causing excessive heat . Then instead of the motor pulling the expected 9.8 amps, the motor will now be pulling 12.25 amps considering the lower voltage available to do the same work that the motor is designed to produce.

If we take the same motor at 125 volts with a load of 9.8 amps and with an approximate charge of 10 cents per Kw. usage from your power company, and running the motor 24 hours a day, for 30 days of the billing cycle. You would be charged approximately $ 88.20. If we ran that same motor with 100 volts with a 20% voltage drop the same amount of time at the same rate per Kw cost, you would be charged approximately $110.50. This would be an increase of electric usage cost of $22.05 per month or $264.60 per year for the same motor to do the same amount of work. This increase of cost is caused by loss of the electricity that you paid for but did not receive due to a voltage drop inherent in your electrical design.

As you can see just increasing the conductor size one size larger to address your voltage drop could save you money. This one time increase of cost during the initial installation of your larger wire could save you more on your electric bill in one year’s use of your equipment, than the increased cost that you experienced to pay for the larger wire. Then you could experience this savings every year during the life of your home. An example of this type of excessive inherent cost that you should consider due to your wiring design causing an excessive voltage drop in your home would be your furnace, your pool pump, your heat pump, your refrigerator, your electric water heater, etc. You would experience different savings on each appliance, but the calculations of voltage drop in your wiring designs should be worth your time. This is due to the automatic running of your equipment, off and on, 24 hours 7 days a week, whether you are there or not, or like a pool pump running non stop 24 hours a day 7 days a week.

I wrote the above paragraphs hoping to paint a picture in your mind as to how a voltage drop can be reduced and how addressing a voltage drop could save you money. I also wanted to show where you may design a circuit addressing your voltage drop causing cost savings well worth your time to investigate.

You also could use a step-up transformer in order to reduce the voltage drop present at end of line, instead of increasing the conductor size. Any means of adjustment in your wiring design should be acceptable that is above the minimum set by the NEC.

Now you should see why some people pay more per month on the electric bill than others do. The life style of your family, leaving coffee pots on, increasing the thermostat of your water heater, furnace, air conditioner, etc. can cause you to pay more than your neighbor that has the exact same house. Voltage drops present in your original wiring design will cost you more money on your electric bills than your neighbor pays for a house that is exactly like yours but wired by a different electrician with voltage drop considered when they wired your neighbors home. You could pay more on your electric bill than your neighbor and be more frugal on your equipment usage then your neighbor, just because you didn’t consider voltage drop when you wired you home.

The formula to calculate a voltage drop concerning single phase wiring in your wiring designs is

Voltage Drop = (2xKxLx) / CM

The “2” stands for the wire going from the panel to the equipment {hot}, and the second wire returning the path back to the panel {grounded} for 125 volt circuits. For 240 volts circuits the “2” stands for the two hot conductors running to the equipment. No return path would be required for 240 volt circuits with no neutral conductor carrying the unbalanced load. If you have a circuit that has two hot conductors and a white or gray conductor then you would have a 240 volt multi-wire circuit. A 240 volt multi-wire circuit would be calculated as two 125 volt circuits, because the white or gray conductor is no longer just a grounded leg {return path}. This conductor is now a neutral conductor that carries the unbalanced load between the two hot conductors. In most occasions you would not experience a three phase circuit in a dwelling setting. If you do have a three phase circuit then you must substitute “1.732” in place of the “2” to calculate a three phase voltage drop. The “1.732” stands for the square root of the three hot conductors used in a three phase circuit.

The “K” stands for the resistance of your conductor per 1000’ found in the NEC Chapter 9 Table 8. To find “exact K” you would calculate the resistance of your conductor size and type then multiply times the circular mill of your conductor then divide by 1000. This would be “exact K”. “Approximate K” would be 12.9 for copper or 21.2 for aluminum.

The “L” stands for the distance one way from your power source {transformer} to your equipment.

The “I” stands for the load in amps of your equipment. Then divide this answer by the circular mill of your conductor found in the NEC Chapter 9 Table 8.

You might plan to reduce your wire size in a circuit that you are wiring to save money {cost}, or voltage drop {using the larger conductor at the beginning of a circuit then reduce the size at the end of a circuit. You could use the following as an example of a conductor being reduced, in size, in a circuit. You might run into this different conductor sizing in the same circuit if you tried to run 12 Ga. from a panel, then run 14 Ga. to your switch legs to save money. If you do reduce a wire size in a circuit, you must reduce the overcurrent device size to meet the maximum allowed overcurrent device {breaker or fuse} to meet the maximum ampacity of the smallest conductor in the circuit. Be careful doing this type of design. You may not meet the minimum ampacity required on a circuit such as a 15 amp fuse or breaker on a 20 amp circuit that is required in the kitchen, bath, and laundry. 210/3

INSTALLING YOUR WIRES

[ NON-METALLIC SHEATHED CABLE ]

WITHIN YOUR DWELLING, WILL BE OUR NEXT SUBJECT.

You may make a junction almost anywhere you like, keep in mind that you must keep that junction accessible. 370/29 Junctions must be contained within a box. 300/15, and must be with a legal connections {compression style connection} 110/14 Be careful about using junction on resistance heat, and heavy motor loads. These are trouble areas due to deterioration caused by the excessive heat of larger or continuous loads.

Remember that you must not use conductors smaller than 14 Ga.. You must not use voltages above 120 volts to ground, in a dwelling. 210/6/A

INFORMATION FOR THE CALCULATIONS CONCERNING BOX FILL

Watch that you don’t overfill the junction boxes. 370/16 such as switches, receptacles, or junction boxes, etc.

IF YOU ARE USING CONDUCTORS SMALLER THAN 4 Ga. AND ALL THE SAME SIZE CONDUCTORS IN THE BOX USE THE FOLLOWING

We must first find the maximum numbers of conductors allowed in the box that you are using.

When you are calculating the total number of current carrying conductors in a box, in addition to counting all actual current carrying conductors as one current carrying conductor for each conductor {any color of conductor except, green or bare}, you must add the following as current carrying conductors as follows; Article 370/16 Each device {switch or receptacle} found in the box must be counted as 2 more current carrying conductors, all grounding conductors in that box must be counted as a total, as one more current carrying conductor, and all clamps must be counted with the total number of clamps found in the box as one more current carrying conductor. Keep in mind that you are not supposed to count conductors that neither enters your box nor leaves your box. [pigtails only, these are ignored].

If you are using a steel box that is listed in the NEC chart 370/16/A, then the chart should give you the maximum current carrying conductors allowed in the steel box. A further calculation of adding up the number of current carrying conductors that you must count as being in that box, by your wiring design must be calculated. The total number of current carrying conductors that you designed to be in that box must be compared to the maximum allowed in that box. The total number of current carrying conductors that you designed to be in that box must not exceed the total number of current carrying conductors allowed in that box.

You may also use the following method of calculation if you don’t have a Code book, are using a size of steel box that is not listed in chart 370/16/A, or you are using a plastic or fiber box. If you are using a type of box that is not listed in the NEC chart 370/16/A, then you must measure the box, then multiply the height times the length times the depth of the box to find the cubic inch capacity of that box. Now you must look in the NEC chart 370/16/B to find the cubic inch required per conductor rated by the size of the conductor that you are using. The chart mentioned says that 14 Ga. = 2 Cu. In. per conductor, 12 Ga. = 2.25 Cu. In. per conductor, 10 Ga. = 2.5 Cu. In. per conductor, 8 Ga. = 3 Cu. In. per conductor, 6 Ga. = 5 Cu. In. per conductor. 370/16/B If you are using all conductors of the same size in your box, then you must count the number of current carrying conductors [all colors including white but not counting green or bare] entering your box. Also do not count conductors that neither enters your box nor leaves your box. [pigtails only, these are ignored].

Now add to your number of current carrying conductor list, by counting all of the grounding conductors as one conductor [green or bare], no matter how many grounding conductors, just add the one conductor to your total number of current carrying conductor list. All grounding conductors [green or bare] must be counted as a total of one current carrying conductor.

Clamps are also counted the same as grounding conductors, one current carrying conductor must be added for the total of all clamps found in the box. All clamps found within your box that are entering the box at least ½”, no matter how many, count as one current carrying conductor, only, for all of these clamps. Now add this one conductor count to your total number of current carrying conductor list, if any of these clamps are present. A single gang plastic or fiber box will have no clamps to consider. They are exempt from a clamp requirement.

Devices must count as 2 conductors for each device. Count the number of devices {switches or receptacles}. Multiply the total number of devices times 2. The answer from multiplying the total number of devices by the 2 is the total number of current carrying conductors you must add to your total number of current carrying conductor list.

Now this final total of your current carrying conductor list is the answer to the total number of current carrying conductors installed in your box.

Now multiply the Cu. Inch required for the size of conductors in your box found in the 370/16/B by the answer that you found in your total number of current carrying conductor list. This is the total cubic inch required for all of the conductors, equipment, and devices in your box. Compare this total cubic inch required to the total cubic inch capacity of your box. You must not exceed the capacity of your box with the total cubic inch required by your conductors, equipment, and devices that you installed in that box.

IF YOU ARE USING CONDUCTORS SMALLER THAN 4 Ga. AND DIFFERENT SIZE CONDUCTORS IN THE SAME BOX USE THE FOLLOWING

If you are using different size conductors in the same box. You must perform the same conductor count and calculation as if using all of the same size conductors in your box as described above except the following. You must change the current carrying conductor calculation into separate calculations for each size conductor times the assigned cubic inch required in the 370/16/B. You must also change the counts calculation for your devices and clamps calculating them as if they were the largest conductor in the box, when you use the 370/16/B. Ignore any smaller conductors for the device and clamps calculations section. Only consider these equipment and devices as the largest size conductor present in your box to calculate the current carrying conductors that you must add to your list for these equipment and devices. You must also change the one conductor count for the total number of grounding conductors using the largest grounding conductor size found in the box, when you use the 370/16/B.

Then add all of the cubic inch requirements from your list, all added together, for the total cubic inch required and compare that total cubic inch required to the cubic inch capacity of your box. You must not exceed the total cubic inch capacity of the box by the total cubic inch required for the conductors, equipment, and devices present in your box, as you have calculated.

IF YOU ARE USING CONDUCTORS 4 Ga. OR LARGER THEN REFER TO 370-28 OF THE NEC

If you have boxes with conductors larger than 4 Ga. that are installed in a box, then you must calculate in a different manner. In short, a box with 4 Ga. or larger conductors must be calculated by adding the diameter of all of the conduits on the same side of the box and in the same row for the first total. Then add each row installed on that same side of the box. Now pick the largest one row total, of each of the rows, and use that in your calculation. Ignore the other rows on that side of the box. Now pick the largest conduit in that largest row and multiply that conduit diameter times 6. Now add the total diameters of all of the conduits in that same row to that times 6 multiplication answer. Ignore all of the other rows on that same side. This answer is the minimum distance in inches that the opposite wall of that box must be from that side that you calculated. Now calculate each side of the same box for the answer to the distance required to the opposite wall of the box from each side that you calculate. This is the size of box required to contain the 4 Ga. or larger conductors.

There is a minimum distance allowed between the conduit on one side of a box that contains a conductor going to a conduit on an adjacent side of the box in an angle pull, or the same side of a box in a “U” pull. You must take the largest of the two conduits containing a conductor of an angle or “U” pull and multiply that conduit by 6. The answer to this multiplication would be the minimum distance between two conduits containing the same conductor in an angle or “U” pull.

If you are using nonmetallic sheathed cables with 4 Ga. or larger in them then you must measure the widest point across the nonmetallic sheathed cable and treat this measurement as the diameter of a conduit in your calculation. The intent of the nonmetallic sheathed cable widest point is to find the size of conduit required to contain than nonmetallic sheathed cable. The calculations to discover the size of a box with 4 Ga. or larger conductors gets more complicated but it should give you a general idea on the subject. 370/28/A/2

INSTRUCTIONS ON CLOSET LIGHTING

You must have 18” clearance from the back and side walls of a clothes closet from the nearest edge of the recessed tank trim. You also have to meet another clearance requirement of 6” from any shelf in the clothes closet to the nearest edge of the recessed tank trim of the lighting fixture. 410/8

You must have 18” clearance from the back and side walls of a clothes closet from the nearest edge of the florescent fixture. You also have to meet another clearance requirement of 6” from any shelf in a clothes closet to the nearest edge of the florescent fixture. 410/8

You must have 24” clearance from the back and side walls in a clothes closet from the nearest edge of an incandescent fixture. You also have to meet another clearance requirement of 12” from any shelf in a clothes closet to the nearest edge of the incandescent fixture. 410/8

Any incandescent fixture whether surface or recessed must be with a closed lens enclosing the incandescent bulb or bulbs. 410/8

DESCRIPTION OF A FAN BOX

You must install a fan to a box approved and listed for use in supporting a paddle fan. Any box listed and approved for the purpose, should be built like the following; The Code does not want you to rely on the tabs normally threaded to accept the 8/32 support screws. Instead, that tab will have a larger hole letting that 8/32 screw slide through to the back of the box to threads in the back of that box. This box will be threaded in the back of that box, if steal, or the box will have a nut molded in the back of the box, if it is plastic. This type of box, listed and approved for a fan, may be available in plastic or steel. These fan boxes may even be pancake boxes listed and approved for use supporting a paddle fan. 422/18 and 370/2

INSTRUCTIONS ON SMOKE DETECTOR REQUIREMENTS

Smoke detector requirements are found in the CABO Residential Building Code Book. These smoke detector requirements were adopted by the State of Indiana as the rules to govern by the Authority Having Jurisdiction. The smoke detectors are required to be installed in a permanent manner. The smoke detectors are required to be 120 volt powered, and with battery back up. These smoke detectors are required to be installed within each bedroom, in the vicinity of each bedroom area {hall}, and at least one on each floor including a basement. These smoke detectors must be 120 volt powered with a red or yellow conductor that ties all smoke detectors together on a third wire so that if one smoke detector sounds off then they all must sound off. When it comes to the smoke detector rule, the term existing does not apply. This smoke detector rule applies to all dwellings.

EXPLANATION OF CABLING OF WIRES.

THE CODE SAYS THAT IF YOU "CABLE" MORE THAN THREE WIRES IN A BUNDLE {Romex bundled together}, IT BECOMES THE SAME AS A CONDUIT. IF THE CONDUCTORS ARE CABLED THE AMPACITY OF THOSE CONDUCTORS MUST BE DE-RATED, IF OVER 4 CONDUCTORS. IN A RACEWAY.

Cabling is when you run several nonmetallic cables {Romex} together in a group for a distance of more than 24”. 310/15/B/2/A

WELL PUMP WIRE REQUIREMENT

Check the writing on the side of the pump wire. This wire must be marked as listed for use as a pump wire. If the pump wire is rated as type XHHW, THW or TW, the conductor is approved for a wet location. This pump wire is not approved to leave the protection of the earth without being protected by a conduit. This pump wire is allowed to be direct buried, if marked “pump wire”. The pump wire designation says it is approved for direct burial without a conduit protecting it while in the earth. Type XHHW, Tw and Thw that are approved for use as a pump wire, is approved in a wet location but must be protected by a conduit if leaving the protection of the earth. Otherwise, without the pump wire designation, you must use a wire marked with a “U” designating approved for direct burial. If you use a pump wire, the wire must be protected by a conduit, all of the way to the load after its leaving the protection of the earth. You may transfer the pump wire to a Romex cable {type nonmetallic sheathed cable} upon entering the crawl space and leaving the earth. You may then continue on to the pressure tank without protection if you change to Romex upon entering the crawl space. The type UF cable if used instead of the pump wire is equal to the pump wire and the Romex cable {nonmetallic sheathed cable}. Type UF cable can run from the submersed pump motor in the well under the water to the pressure tank without protection at any point unless subject to physical damage. Subject to physical damage would be if you surface from the trench outside then pass into the dwelling from the outside. 339/3/B While it is down low to the ground and outside it is considered as subject to physical damage and must be sleeved in a conduit. Type UF cable must be supported as per the NEC requirements for Romex upon entering the structure. {every 4 ½ feet} The pump wire may not run unprotected once leaving the earth or in the crawl space unless it is type UF with an outer covering like a Romex cable in design.

Check to see if the capacitor bank is built into the motor. If the capacitor is in the pump and not in the dwelling, near the pressure tank, then you may run only two insulated conductors to the pump. If the capacitor bank is remote from the pump itself, then three insulated conductors must be ran. All current carrying conductors including neutrals and grounded leg conductors must be insulated. 339/2 and the commentary in the Handbook

INSTALLING YOUR WIRES “ROMEX” [NON-METALLIC SHEATHED CABLE] WITHIN YOUR DWELLING

You may run your wires within the studs, within the attic, within the crawl space, within the areas between the first floor ceiling, and second story flooring. 339/3/A/4 You may even run the nonmetallic sheathed cable on the surface as long as there is not a danger of physical damage. 336/1 through 336/31 If you run surface on the wall, most people consider above 4 feet or behind an object protecting such as a large plumbing pipe would be not subject to physical damage. Behind a large appliance is consider subject to physical damage because the appliance itself could damage the Romex.

When running within the walls, and between the ceiling, and flooring, you must keep the holes beyond 1 ¼” from the surface, or protect that wire, from damage, with a 1/16” steel plate. 300/4 You may run your wires within a cold air duct, only if running across it {perpendicular}, and not along it {parallel}, while within the duct. 300/22 Exception You may run more than one wire per hole, anywhere you normally would run one, but be careful not to create a cabling effect. If a cabling effect happens, then you must de-rate the wire, according to 315/B/2/A, counting each conductor, within each cable, with the exception of the grounding conductor. If cabling happens {cabling = several Romex cables running through a series of the same line of hole, for more than 24”} then you will de-rate the ampacity of these cables quickly. A 20 amp circuit will quickly become a 5 amp circuit or less, even though that wire was originally rated at 20 amps. 310/15/B/2/A Do not use cable ties to bundle Romex for a distance of more than 24” because you would again be creating the cabling effect again.

DRILL YOUR HOLES AT ONE SETTING

If you plan to wire running, up the studs, and through the attic, then I suggest that you use an auger bit, around 7/8to 1” size. I suggest that you drill one hole through the top plate, over each receptacle and single switch box. Now, drill two holes, over each double switch box. Then drill three holes over each three or four gang switch box. This is a nice wiring style, and I suggest that this style of wiring should be considered, if possible

If you plan to wire through the crawl space, then drill the same number of holes through the bottom plate. I don’t suggest this type of wiring style because it creates a lot of crawling, and a lot of supporting of the wires, in the crawl space that will hang like sway back clothes lines, without the required support. This style of wiring creates a lot of extra work supporting the hanging wires in the crawl on running boards. 336/18 and 300/4 You must install the Romex running along the framing members or on running boards. 300/4/D

If you plan to wire through the studs, then I suggest that you place the drill against your hip, both for support, and even hole placement. I suggest that you drill one hole per stud, unless you know that a lot of wiring will be installed across a certain wall, and adjust as necessary. You should drill your holes as straight as possible, for ease of pulling the wires through those holes. You will need to take special consideration, at the corners. You can turn a corner by drilling both directions making the holes meet within the corner studding. When you pull a wire around this type of corner, you must bend the wire to a form a curve in the wire, then wiggle it through the holes drilled in that corner. It get easier the more often you install a wire through the holes in the corners.

Joist and rafter must not be notched in the middle third of a framing member, and the notch must not exceed 1/6th the depth of the framing member. CABO 3902.1 and 502.6 Joist or rafters must not be drilled within 2” of the surface of the framing member and the hole must not be drilled with the hole larger than 1/3rd the width of the framing member. CABO 3902.1 and 502.7

STRINGING THE WIRES THROUGH THE HOUSE AND DESIGNING THE CIRCUITS PATHS

Please keep in mind that you must size your breaker in the panel protecting that circuit to the maximum ampacity of the smallest conductor found in that circuit

As you design your “switch system” wiring pattern, you should consider running the power runs from the service panel or other box into switch boxes. This will allow you to make it more convenient to split off in a wye pattern to feed other boxes. Receptacles, in single receptacle boxes, take up too much room in the box to run more than one power out from that receptacle box to other boxes. Also, running more than one power out from a receptacle box also requires wire nuts not needed if no power outs exist in that box, except the wire nut for the grounding conductor. Putting power ins and power outs in the switch boxes will allow you to be able to, more easily, keep within the maximum box fill requirements, and still not have to fight to install the devices of that box. This is especially true in muti-ganged boxes such as triple and four gang boxes which have more cubic inch capacity. 370/16

You should consider designing a three, or more way switch system, by the following suggestions. These suggestions will allow you ease in remaining within the box fill maximums. Run a cable with two insulated conductors in it as power to one of the end switch boxes, of the three way switch system. Consider this the start of the system. Then go from that box to the next switch box, within the same switch system, using a cable with three insulated conductors. This will be the other end, of that three way switch system. Now run a two conductor cable from that end switch box to the light fixture. This will be the switch leg box which is the box at the opposite end of the three way switch system that you ran the power into.

Now to repeat, in short what we just said; From power source to the first switch box , then from the first switch box with the power cable in it to the second switch box , then from the second box with the three conductor cable in it to the light fixture box> two insulated conductor cable>, then from the first light fixture box to the second light fixture box, if more than one light is controlled by the same three ways switch system. Congratulations ! You wired your first three way switch system. Remember that the white wire in a 12/3 or 14 / 3 cable, that contains a black, red, white, and a bare, must be used as the grounded conductor only and the bare or green conductor must be used as the grounding conductor only. 200/7/C/2

If you wire nut the white wire of your power source going into the first box to the white wire in the 12 /3 or 14 / 3 cable, then the white wire of the 12/3 or 14 / 3 cable entering into the 2nd box to the white wire of the 12/2 or 14/2 cable going to the light fixture, you would just be extending the white wire of the power source from the first box through the 2nd box to the light fixture.

This will leave you two blacks and one red in each box to connect to your three way switch. You should take the black of the 12/2 or 14/2 cable supplying the power coming into the first box and connect this black of the 12/2 or 14/2 cable to the common screw. {black screw} Then connect the black and red of the 12/3 or 14/3 cable coming into that box to the two traveler screws of the three way switch. {two copper screws} These two travelers may be installed on either of the two copper screws on the three way switch that is not marked common {black screw}. 200/7/C/2

If the switch system is a four or more way switch system then run a two insulated conductor {12/2 or 14/2} cable from a power source to the first switch box of a four or more way switch system, then come from that first box and go to the next nearest switch box, within the same switch system using a cable with three insulated conductors {12/3 or 14/3}. Now go to the next nearest switch box again using a three insulated conductor cable {12/3 or 14/3}, and repeat from the switch box to switch box with three conductor cables {12/2 or 14/3}, until you have reached the last switch box designed for the switch system. This last box should be nearest to the light fixture. You should, then, run a cable with two insulated conductors {12/2 or 14/2} from the last {other end} switch box, of this certain switch system, to the light fixture, or fixtures, as a switch leg allowing all of the locations, of this certain switch system, to control the light fixture{s}in an unlimited manner.

Most single gang plastic, and fiber boxes will hold three 12/2 cables or two 12/2 cables and one 12/3 cable. and be within the Code’s maximum box fill requirements, even with a receptacle or switch in that box. Use this “Rule of Thumb” method, in your design to maintain ease of design or refer to 370/16 of the NEC. I suggest that you use your double, or larger switch boxes, if you want to branch off into two or more directions. These larger boxes allow more conductor fill, thus permitting you to branch in a “wye pattern” with your power ins and power outs in more than one direction on the circuit. You may also use a light fixture box as a junction box, if necessary, but I suggest that you run power to the switches, and then a switch leg, only, to the fixture box. You should experience less confusion, if you keep your power ins, and power outs, at the switch box locations.

In 2,3 or 4 gang switch boxes you should mark what the wires are to be used for in that box. You should mark at the boxes of a three, or more way switch system, where you are running power, and which ones will be switch legs, and then mark all of the rest of the switches within a four or more way switch system, as a 4 way switches. You can do this by marking a small “p” over each switch system yoke {holder of a device} that will be the power end of the system, and a “S/L” over each switch system yoke, that will be going to the fixture, and a “4w” over each yoke that is in the middle of a four, or more, way switch system. Then mark a big “P” with a red crayon, telling where you will be starting each branch circuit from the panel {Power Run}

INSERTING THE WIRES INTO THE BOX

When inserting the cables into a switch box, I suggest that you make a pattern of keeping all power ins, and all power outs, inserted “closest to the stud”, then the switch legs, in the order that they will be used, as you have marked previously on the studs. This method of identification will help in the dressing of the boxes, by letting you know what wire is what.

When inserting the cables into a box, you should pull the cable to the box, and grasp it with your thumb, and forefinger, then lay your strippers against the cable, that is beyond where the cable meets the box. You should measure around 6”, 300/14 then cut the cable off, after the 6” tail is allotted. Now strip the sheathing from the insulated wires where the cable met the box. Now insert the wire into the box. The holes in the boxes must be effectively closed, if not in use by a cable 110/12/A If you are using a steel box 370/17/B or a double gang plastic, or fiber box 370/17/C, then you should clamp the wire at this time. Some plastic, and fiber boxes have screw type cable clamps, and some have automatic cable clamps like Chinese fingers style claps molded into the plastic box. All steel boxes must clamp the cable into place, within the steel box. 370/17/B all double or larger, ganged nonmetallic boxes, must be clamped within the box. 300/17/C Single plastic, and single fiber boxes, are exempt from cable clamp requirements. 300/17/C Exception The steel boxes have no such exception. All steel boxes must be grounded using an approved grounding screw, installed in the back of the steel box where a threaded hole is made, by the manufacturer, to fit the green ground screw. 250/126

MAKING YOUR FINAL CONNECTS WITHIN THE BOXES

You should dress all of the connections within all boxes, before you insulate, or drywall. If you don’t know what a cable is for, or where it came from, then you can easily back trace it, if the insulation and drywall has not been installed and the framing is still open. Be sure to either crimp or wire nut each connection, including all of the bare grounding wires within the dwelling. 300/12 I require, within my jurisdiction, that all connections, within a box, to be dressed {with wire nut or crimp} upon rough-in inspection. This local requirement will allow me, to easily see, these finished boxes, minus the devices, to be correct, without removing the devices, on the finish. This local requirement will provide us with less of a chance of staining the walls, with finger prints during an inspection. This local requirement will allow me to see more while the walls are still open 90/4 {Authority having jurisdiction} You should wait for the drywall to be hung, and finished before you install the devices, {switches and receptacles}.

You may now ask for a rough-in and power to panel inspection. I allow power to the panel, once the rough-in has been approved, and the service has been built, and the meter base installation has been approved, within my jurisdiction. Some areas require occupancy approval, before, the power is allowed to be permanently connected, by the Utility company. You must not insulate, or cover any electrical work, without prior rough-in inspection approval, from your local inspector’s office.

You should install all of your devices, and all of your fixtures, and all of your equipment, after the walls are finished, and installed have the drywall. You may use the screws of the devices if 12 Ga. and / or the plug in slots if 14 Ga. provided on the devices while installing your fixtures, and devices, if so designed.

Remember that you must have all of the following protected by a ground fault circuit interrupter, all of the receptacles in the bathrooms, 210/8/A/1 all of the receptacles outside, 210/8/A/3 all of the receptacles over the kitchen counter, 210/8/A/6 all of the receptacles in the garage within approximately 8’ {readily accessible} of the floor area {with the exception of behind a large appliance such as a refrigerator, freezer, washer, or other large appliance, receptacles with single outlets on a dedicated circuit and not readily accessible}[behind the large appliance] 210/8/A/2 All of the receptacles in unfinished basements must be GFI protected with the same large appliance exception that would apply here also. 210/8/A/5 All receptacles in a crawl area including sump pumps 210/8/A/4 All receptacle within 6’ of the wet bar 210/8/A/7

Remember that the bathroom, kitchen, dining room, nook, pantry, and laundry receptacles must not be mixed with anything else on those circuits. An exception to the above statement is that the kitchen, nook, dining and pantry may be on the same circuits with each other but nothing else is allowed on those small appliance branch circuits..

You must provide a 20 amp receptacle adjacent to each bathroom lavatory sink bowl, but not more than 36” from the bowl, and on a 12 Ga., 20 amp circuit. This circuit must be GFI protected. The bathroom circuit may be wired with two different designs at your choice.

CHOICE # 1 - If you run a dedicated circuit to each bathroom and keep that dedicated circuit within that certain bathroom, then you may run everything in that one certain bathroom on the same circuit, including a whirlpool bath and that bathroom’s receptacles and that bathroom’s lighting. Remember that the bathroom receptacles on that dedicated bathroom circuit must be GFI protected. You may run everything in that bathroom on the dedicated circuit and then install a GFI receptacle at the end of the circuit to protect the bathroom receptacles only. This is true only if without a whirlpool tub. The whirlpool tub must be GFI protected.

Another design for the bathroom dedicated 20 amp circuit is to install a GFI breaker in the panel, or install a GFI receptacle in the bathroom on the first device in that circuit to protect everything in that bathroom, then a whirlpool tub may be installed on that circuit because it will be GFI protected.

CHOICE # 2 – If you run a dedicated 20 amp bathroom receptacle circuit and install a GFI receptacle on the first receptacle on that dedicated bathroom receptacle circuit, or a GFI breaker in the panel serving that circuit, and only install bathroom receptacles on that dedicated circuit, then you may install all of the bathroom receptacles in all of the bathrooms on that dedicated bathroom receptacle circuit. Remember no other device would be allowed on that bathroom receptacle circuit, not even in the bathrooms, if you use option #2 and run a dedicated bathroom receptacle “only” circuit. If you decide to install all of the bathroom receptacles in all of the bathrooms on one 20 GFI protected circuit, then anything in those bathrooms must not be on the dedicated bathroom receptacle circuit. If you decide to use option #2 in your wiring design of the dedicated bathroom receptacle circuit, then you may run the lighting in those bathrooms on the receptacle or lighting circuits in the bedrooms or living rooms. 210/11/3 and 210/8/A/1

You may run the GFI protected receptacles in the garage, basement, outside, and crawl all on the same circuit. Do not mix those mentioned in the prior sentence with the small appliance branch receptacles in the kitchen, nook dining, or pantry. Do not mix those receptacles mentioned in this paragraph’s first sentence with the bathroom receptacle or laundry receptacles, either. 210/11/C Remember that the sump pump and all other receptacles in the crawl space must also be GFI protected 210/8/A/4

Remember no structure may be occupied until all final inspections have been approved by the “Authority Having Jurisdiction” as follows;

Building, Plumbing, Electrical Inspectors and the Board of Health and then You must have received a letter of “Occupancy Approval” from your local Municipal Planning Commission Director’s Office

This document is based on the 1999 national electrical code and is designed to give you an option, as a self-help, that should pass minimum code requirements. While extreme care has been implemented in the preparation of this self-help document, the author and/or providers of this document assumes no responsibility for errors or omissions, nor is any liability assumed from the use of the information, contained in this document, by the author and / or provider.

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