Neutral Size

[mstrlucky74]

Whats purpose of over-sized neutral?

 

[roger]

It was for odd order harmonics during the paranoria years and it has gotten permanately stuck in some designers minds.

Roger

 

[infinity]

Commonly known as a 200% neutral. Technically the ungrounded conductors have been upsized so the EGC may be too small.

 

[ptonsparky]

Commonly known as a 200% neutral. Technically the ungrounded conductors have been upsized so the EGC may be too small.

I thought in most cases the neutral was the grounded conductor.

You bring up a point though, do I have to increase the size of the EG when the neutral is oversized but not the Phase conductors? I wouldn’t, but I’ve been wrong at least once....in the last 10 minutes.

 

[infinity]

I thought in most cases the neutral was the grounded conductor.

You bring up a point though, do I have to increase the size of the EG when the neutral is oversized but not the Phase conductors? I wouldn’t, but I’ve been wrong at least once....in the last 10 minutes.

250.122(B) references increasing the EGC only when the ungrounded conductors are increased in size.

 

[charlie b]

Technically the ungrounded conductors have been upsized so the EGC may be too small.

We don't know that. The OCPD could be a 100 amp breaker. That properly corresponds with a #2 ungrounded conductor and a #8 EGC.

 

[infinity]

We don't know that. The OCPD could be a 100 amp breaker. That properly corresponds with a #2 ungrounded conductor and a #8 EGC.

Could be or maybe not. #3 THHN is a 100 amp conductor so #2 would be an increase in size from #3.

 

[mstrlucky74]

We don't know that. The OCPD could be a 100 amp breaker. That properly corresponds with a #2 ungrounded conductor and a #8 EGC.

It is 100A MCB.

 

[kwired]

Could be or maybe not. #3 THHN is a 100 amp conductor so #2 would be an increase in size from #3.

I agree, EGC likely needs proportional increase in size in this case unless we can come up with a detail that says #3 isn't a 100 amp conductor for this application.

 

[ptonsparky]

I thought in most cases the neutral was the grounded conductor.

You bring up a point though, do I have to increase the size of the EG when the neutral is oversized but not the Phase conductors? I wouldn’t, but I’ve been wrong at least once....in the last 10 minutes.

Scratch this....now I see where you came up with oversized phase conductors.:dunce: