no confusion concise definition

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megloff11x

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I was wondering if anyone could suggest a lawyer-proof, invulnerable to confusion and misunderstanding statement that defines the whole grounding, bonding, and neutral issue in a few concise sentences. The problems I have paring it down are the exceptions and special cases.

Matt
 
Re: no confusion concise definition

I'm trying to explain this to a group who may have to make an informed decision sporadically and need a quick way to decide if what they're being told is correct or not, aka managers.

Matt
 
Re: no confusion concise definition

The grounding and bonding portion of the question is easy. The NEC has already provided defintions and explanations for both issues. See Article 100 and 250.2 and especially 250.4(A)(1)-(5) - these are the only legally defined and enforceable staetments. Anything someone makes up or derives from another source carries no weight.

The "neutral" issue is not so clear as the NEC does a poor job or define and explaining what it is. In this case, other references such as IEEE or other technical documents. A good description is simply that a "neutral" is a grounded conductor that carries the unbalanced load of a multiwire connected circuit.
 
Re: no confusion concise definition

The grounding and bonding portion of the question is easy.
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I don't think so. Most of what the NEC calls grounding is, in fact, bonding.
Don
 
Re: no confusion concise definition

The frequent question is, Neutral and Ground are tied together, why do I need the extra wire?

My best short answer is that Neutral normally carries current back, Ground only carries current back in a fault condition and then to trip the breaker. The ground wire is effectively a dead end in normal operation.

Then we have to on into discussing ground noise, lightning bolts, why a local stake in the dirt won't cut it (or shouldn't), and the confusion increases.

I get confused and have to go back to the book.

It's that old, you don't understand it unless you can explain it to your grandmother issue.

Matt
 
Re: no confusion concise definition

I completely agree, but try telling that to a lawyer and judge.

"No your honor, I am not an engineer, and no I don't represent the NFPA, and yes I am only a modest electrician, but I tell the NEC is wrong!"

"We find the defendant insane and incapable of defending himself. Please send him to the sanitarium for further evaluation."

:p
 
Re: no confusion concise definition

Just curious, why do the mangers need to know the technical reasons?

Wouldn't the fact that these things are required by the accepted codes be enough information to make a decision?

[ January 16, 2006, 01:36 PM: Message edited by: iwire ]
 
Re: no confusion concise definition

Feeding them theory of grounding would be bad.

They need to know what shall be required, shall be permitted and shall not be permitted by the NEC. A daunting task for someone with no background in electrical.
 
Re: no confusion concise definition

As far as bonded or grounded, I kinda like Art 100 definitions, as Bryan says, "neutral" isn't as simple, but his definition is the best I've heard.
 
Re: no confusion concise definition

The words "concise", "grounding", "bonding", and "neutral" can not be used together.

Roger

[ January 16, 2006, 02:50 PM: Message edited by: roger ]
 
Re: no confusion concise definition

I've worked on past legal cases involving grounding and protection. I usually found the lead lawyer to be quite capable of understanding and questioning about the subject matter. Dealing with an upstanding lawyer - well that's the rub!!

To your point, the NEC is a "code of rules" with no intent to expound and educate on the why's and wherefores. That's left to the scientific community. For the USA, that is primarily the IEEE and other ANSI standards groups. Likely, the best available is IEEE Std. 142 and IEEE 1100, both of which are revised but not yet published to that revision. Still, in the existing versions you can find the info you seek. To add: For typical USA grounded systems: Equipment grounding conductors are for safety (returning fault current back to the supply via the neutral) and for aiding electromagnetic compatibility of the equipment and cabling. The neutral (where so identified) is for returning the load current back to the supply. Generally, the supply is made into a grounded system whereby the neutral is the conductor that gets grounded. Equipment grounding conductors are bonded to the same grounding source as the neutral. Really way simple concept. No need to overconfuse.

William Bush
Director of Engineering
SPGS, inc.
 
Re: no confusion concise definition

Originally posted by megloff11x:

My best short answer is that Neutral normally carries current back, Ground only carries current back in a fault condition and then to trip the breaker.
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It's not technically correct to use the term "back" as it implies the current is only flowing in one direction. The neutral does indeed carry the unbalanced current of a system, but it is not uni-directional flow in an AC system. Likewise, under a fault condition, there is not uni-directional current flow on an EGC or GEC either.
 
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