Grounding VS Bonding

[bori]

:?Good afternoon, in grounding VS bonding DVD Mr. Holt states that a groun fault is when a hot wire comes in contact with any metal part in system. would it not be also if it contacts a grounding conductor, ie bare, or crushed together?. Thank you

 

[peter d]

I'm not entirely sure what you're asking, but the term "grounding" is actually a misnomer and has caused much confusion in the electrical industry over the purpose of grounding/earthing and bonding. The primary concern of premises wiring systems is maintaing a low impedance path back to the source, not the earth. This is done via the bonding conductor, which is commonly called the grounding conductor.

Accidental contact between the grounded (neutral) conductor and grounding/bonding conductor is a fault that can be hazardous in some situations but I wouldn't go so far as to call it a "ground fault".

 

[GoldDigger]

Accidental contact between the grounded (neutral) conductor and grounding/bonding conductor is a fault that can be hazardous in some situations but I wouldn't go so far as to call it a "ground fault".

I think what bori is asking about is the contact between a hot conductor and either a grounded conductor or a grounding conductor, rather than "any metal part in the system." Would those conductors also be considered a metal part in the system? Or to put it another way, would that be a ground fault or "just a short circuit"?

 

[peter d]

I think what bori is asking about is the contact between a hot conductor and either a grounded conductor or a grounding conductor, rather than "any metal part in the system." Would those conductors also be considered a metal part in the system? Or to put it another way, would that be a ground fault or "just a short circuit"?

Ahh ok. Well, I'd say a L-N fault is a short circuit, and L-G fault is a short circuit as well, but more specifically a ground fault short circuit.

 

[K8MHZ]

Ahh ok. Well, I'd say a L-N fault is a short circuit, and L-G fault is a short circuit as well, but more specifically a ground fault short circuit.

Also, I think an improper N-G connection could be called a fault. At least in the eyes of a GFCI.

 

[peter d]

Also, I think an improper N-G connection could be called a fault. At least in the eyes of a GFCI.

I agree, an improper N-G connection is most definitely a fault.

Maybe a list would help.

Types of faults:

Short circuits: L-L, L-N, L-G, N-G.
Opens
Intermittent high resistance open aka glowing fault.

 

[Dennis Alwon]

When Mike Holt stated a ground fault is when the hot conductor comes in contact with a metal part in the system then the neutral and equipment grounding conductor would both be involved as they are in contact with the metal parts somewhere along the line.

 

[GoldDigger]

When Mike Holt stated a ground fault is when the hot conductor comes in contact with a metal part in the system then the neutral and equipment grounding conductor would both be involved as they are in contact with the metal parts somewhere along the line.

On the other hand, if the metal part in the system that the hot conductor comes into contact with is ungrounded (usually a violation in itself unless that metal part is inaccessible) then there is not an actual ground fault, and no ground fault detector, including a GFCI, would activate until some hapless person touched the metal.
After all, the commutator of a motor and the terminals of a circuit breaker are in one sense metal parts in the system.

It is always a problem to try to provide an English language description of something like that. You either miss some of the edge cases we are so fond of or you make it unreadable and therefore useless.

 

[Dennis Alwon]

True but I doubt he would be talking about an improper wiring system.

 

[bori]

Grounding VS Bonding

Thank You.