Upsizing the ground wire for voltage drop

[zappy]

So we pulled a 10 gauge hot and neutral, but we pulled a 12 gauge ground. We upsized to 10 gauge for voltage drop, but why don't we upsize to 10 gauge for the ground wire? thank you.

 

[roger]

So we pulled a 10 gauge hot and neutral, but we pulled a 12 gauge ground. We upsized to 10 gauge for voltage drop, but why don't we upsize to 10 gauge for the ground wire? thank you.

Read 250.122(B)

Roger

 

[Dennis Alwon]

So we pulled a 10 gauge hot and neutral, but we pulled a 12 gauge ground. We upsized to 10 gauge for voltage drop, but why don't we upsize to 10 gauge for the ground wire? thank you.

You should have used a 10 equipment grounding conductor.

 

[zappy]

You should have used a 10 equipment grounding conductor.

So even if it's a 20 amp breaker protecting the 10 gauge wire?

 

[ptonsparky]

So even if it's a 20 amp breaker protecting the 10 gauge wire?

yup.

 

[LarryFine]

So even if it's a 20 amp breaker protecting the 10 gauge wire?

Someone could could come along and see #10 and say, "Hey, we can throw in a 30a breaker."

 

[infinity]

So even if it's a 20 amp breaker protecting the 10 gauge wire?

Yes, and it's not for the reason that Larry mentioned.

It has to do with the EGC being too small to open the OCPD.

 

[LarryFine]

I was just keeping it simple.


Although, since you brought it up, it's funny how large a circuit can be and a #10 EGC is still sufficient.

But I do understand the difference that the reason for the conductor sizing makes.


Added: Funnier still, the smaller the breaker, the larger the EGC must be.

 

[ptonsparky]

Make your circuit a 30 - 60 amp feeder and you still only need a #10.

 

[Dennis Alwon]

Make your circuit a 30 - 60 amp feeder and you still only need a #10.

Just to clarify the overcurrent protective device must be 30-60 then you can use the #10 equipment grounding conductor. If you upsize the conductor and kept the overcurrent protective device at 20 then you would have to upsize the equipment grounding conductor to whatever size the conductors may be.

 

[infinity]

Just to clarify the overcurrent protective device must be 30-60 then you can use the #10 equipment grounding conductor. If you upsize the conductor and kept the overcurrent protective device at 20 then you would have to upsize the equipment grounding conductor to whatever size the conductors may be.

And if it's a metal raceway that qualifies as an EGC then in the OP he can just pull out the #12.

 

[ptonsparky]

Just to clarify the overcurrent protective device must be 30-60 then you can use the #10 equipment grounding conductor. If you upsize the conductor and kept the overcurrent protective device at 20 then you would have to upsize the equipment grounding conductor to whatever size the conductors may be.

Along with this line of thought, that feeder worked successfully for years but now the load is less and we replace the 60 with a 20. We all know what we have to do.






Put the 60 back in!

 

[kwired]

The flaw here is you can run a 40 amp circuit with 8 AWG conductors and use a 10 AWG EGC.

You can also run a 60 amp circuit with 6 AWG conductors and use 10 AWG EGC.

But if you decide to run the 40 amp circuit with 6 AWG conductors instead of 8, now you must also increase the EGC even though it is still on 40 amp OCPD.

I can't tell you how many times I have seen 1000-1500 foot runs of 4 AWG aluminum (with 4 AWG AL EGC) on a 30 amp fuse - those fuses do not respond as quickly on long runs with oversized conductors like they do with 10 AWG on a short run, but are still NEC compliant.