Grounding vs. Grounded

[jumper]

alot im kinda new to the trade i might ask again later who knows lol

We are all here to learn.

 

[hurk27]

the question is: Can the grounding conductor be larger than the grounded conductor or vice versa? where does it state this in the nec?

Grounded conductors can be larger then the grounding conductors (in almost all cases it is)
and grounding conductors can be larger then the grounded conductors (in almost all cases they are not)

for feeders and branch circuits larger then 10awg the grounding conductors will be one or two sizes smaller then the grounded conductors, this is because they only need to clear a bolted fault which even at a smaller size they can do very well (remember grounding conductors are not current carrying conductors and don't need to be protected from over load), they only have to clear the breaker within a few seconds.

Where a circuit conductor has to be protect at its continuous rating from overload, the grounded conductor in a service when it is used as a neutral (shared with two or more ungrounded conductors) can be sometimes reduced in size since the amount of unbalance load will be smaller.

So to answer your question see 250.24(B)(1) and see if that will give you the answer your looking for???

 

[Hameedulla-Ekhlas]

In most cases your neutral is bigger than your ground. What is your app?

Jumper,
I have not seen any NEC artical to recommend neutral conductor size bigger yet but it is possible when we have a nonlinear load and harmonic because overheating of neutral conductors due to third harmonic currents flowing through the neutral. The size of the neutral must be increased by 150-200% of the normal size in such cases, depending upon the severity of the harmonics.

 

[Rockyd]

Jumper,
I have not seen any NEC artical to recommend neutral conductor size bigger yet but it is possible when we have a nonlinear load and harmonic because overheating of neutral conductors due to third harmonic currents flowing through the neutral. The size of the neutral must be increased by 150-200% of the normal size in such cases, depending upon the severity of the harmonics.

Are you referring to 310.15(B)(4)?

 

[Hameedulla-Ekhlas]

Are you referring to 310.15(B)(4)?

I have not found such an artical in NEC-2008 artical 310.15(B)(4)(c) has mentioned regarding to nonlinear load that the theoretical maximum neutral current is 1.73times the balanced phase conductor. But it has not cleared the due to nonlinear load the neutral size must be greater.