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Home > Home Wiring USA Archive: NEC 1999 > Definitions and Calculations > Underground Temporary Service Pole (NEC 1999)

# Suggested Wiring Procedures of an Underground Temporary Service Pole (NEC 1999)

By Warren Goodrich

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Grounded aka. ‘Neutral” Versus Grounding

The following definitions are different entities which have the properties of the generic term “Ground”.

Neutral conductor = Grounded conductor {each are the same as the other, just a different name} by National Electrical Code must be White or Gray.

Grounding conductor = Equipment Grounding Conductor by National Electrical Code must be Green or Bare.

Neutral aka Grounded Conductor = The Conductor that is normally a current carrying conductor that carries the unblanced load between two ungrounded {Hot} conductors. White/Gray

Grounded Leg = The conductor that is normally a current carrying conductor that is the return path for one ungrounded {Hot} conductor. White/Gray

Equipment Grounding Conductor = The conductor that is not normally a current carrying conductor that is energized only on a momentary basis when there is a fault between an ungrounded {Hot} conductor and any metal associated to the electrical equipment that can cause a shock to personnel. Green/Bare

The term Ground is a generic term used in the electrical industry referring to several divisions of the form of ground. The following is an attempt to explain the different versions of the generic term.

An overcurrent device {fuse or breaker} will de-energize a circuit for two reasons.

Reason # 1 Too much load on conductor !

The first reason that an overcurrent device {fuse or breaker} will de-energize a circuit is when there is too much current {amps} being carried on the black and white conductor. The overcurrent device is sized to the ampacity of a conductor. When this maximum capacity of the conductor is overloaded due to amps, the overcurrent device {fuse or breaker} is designed to de-energize the circuit. This action of protection is designed to protect the building from fire due to heat produced due to the overload in amps of the conductor’s maximum ratings.

Reason # 2 Hazard to people !

The second reason that an overcurrent device {fuse or breaker} will de-energize a circuit is when there is a direct short from the ungrounded {hot} conductor to the metal associated to the electrical design {metal electrical boxes, metal of appliances, metal of a building structure, etc.}. When this short circuit appears the green or bare grounding conductor sends an electrical signal back to the overcurrent device {fuse or breaker} indicating that there is a fault in the circuit telling the overcurrent device to de-energize. This short circuit protection is designed to protect people’s lives.

After reading the two methods that an overcurrent devices monitors the electrical system for protection of the electrical system’s integrity, you should now understand that the most important conductor present in the electrical industry is the green or bare grounding conductor.

This green or bare grounding conductor is included within the electrical design to protect people from injury or death due to electrical shock!

GROUNDED {NEUTRAL} CONDUCTOR (white or gray)

Grounded is the term normally used in books containing the rules of electrical design for the entity normally called a neutral in the laymen terms. White or Gray

Grounded {Neutral} (white or gray) is the conductor which is a current carrying conductor which is normally designed to carry the unbalanced load carried back to the center tap of a transformer to complete the circuits of two ungrounded {hot} conductors. The center tap of a transformer is considered to be the value of zero of that transformer. A neutral does not normally serve as a return path to earth. The unbalanced load would be a return path for two ungrounded {hot} conductors that are 180 degrees out of sync with each other with the hot voltage level normally provided by the same transformer that the grounded {white or gray} conductor is tapped to the transformer’s center tap.

GROUNDING CONDUCTOR (green or bare)

Grounding is the term normally used in books containing the rules of electrical design for the entity normally called an equipment grounding conductor. In laymen terms. Green or Bare

Grounding {Equipment Grounding} (Green or Bare) is the conductor which is not designed to be, except only on a momentary emergency basis, a current carrying conductor. This equipment grounding conductor is normally designed to carry the electrical fault [short circuit to metal] to mother earth {ground}. This causes the interrupting rating of an overcurrent device {fuse or breaker} to quickly de-energize the circuit. The short circuit would be when the metal associated to the electrical design has become energized which causes a hazard to personnel associated to that metal of the equipment.

Hope this clears up some confusion between the terms grounding and grounded or neutral and the generic term ground.

EXPLANATION OF THE TERM SIGNAL PERTAINING TO WHAT CAUSES A BREAKER TO KICK USING THE EQUIPMENT GROUNDING CONDUCTOR (green or bare)

The term "signal" I wrote is laymen's term to facilitate understanding. Then someone that has extensive knowledge reads this loose description and tries to figure a technical condition. You made the mistake of knowing too much on this piece of a sentence. You are right actually the signal is a second grounding path causing the thermals of the breaker to overheat and kick out just like a reaction when the homeowner plugs in a large air compressor on a small circuit. An overload occurs but not between the white and the black but between the bare and the black. I used the term "signal" to try and separate the two actions. Both the white and the bare do the same action to the breaker only in different mannerisms. Both the bare and the white are connected at the same entity [neutral bar in the main panel of the structure].

The difference that I am trying to show is that the white is the return path causing the breaker to kick only if the appliance pulls too much load causing heat thus protecting only the building itself from fire, and the bare is the return path causing the breaker to kick only if the metals in the structure, that are exposed to occupants of the structure, becomes energized which would cause bodily harm thus protecting people.

The "signal" [breaker should kick] is designed to react when any metals within the structure becomes hot that is approximately 4" square or larger, becomes energized. Short pieces of plumbing such as metal fill tubes to a sink with plastic plumbing would be exempted by the NEC.

Remember the term "signal" as used in the pass out you read is referring to the second grounded leg that is allowed to be bare or green and identified as the equipment ground. This equipment ground is designed to be energized only momentarily or rapidly reacted to, due to the SHORT CIRCUIT INTERRUPTING RATING OF YOUR BREAKER that reads the "signal" of the short circuit load designed to have a life expectancy of a split second or slightly more.

If you look at the word signal for a definition then that is what an equipment ground does in loose translation. This signal causes a circuit breaker to kick rapidly before a load can reach 6 times the amp rating of the circuit conductor. See below;

230-208. Protection Requirements

a circuit breaker with a trip setting of not more than six times the ampacity of the conductors, shall be considered as providing the required short-circuit protection.

I hope that you can now see different values for a circuit breaker to kick out. One value equal to or below the ampacity of the conductor. The second value is up to 6 times the ampacity of that conductor. Try to remember that when a hot hits an equipment grounding conductor a hum occurs. This hum is caused because of the rapid build up of current on that black wire using the bare wire as the return path to complete the circuit. After a short circuit occurs and the breaker kicks off it happened so quickly that the small conductor barely heated up if even noticeable. This is inherent to the short life span allowed on the short circuit reaction.

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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