I have a sauna that is about 100’ from power source, it is 25a 240v I’m using #10 THHN, my question is can I use a #12 ground?

[Rsemp]

I have a sauna that is about 100’ from power source, it is 25a 240v I’m using #10 THHN, my question is can I use a #12 ground?

 

[winnie]

I have a sauna that is about 100’ from power source, it is 25a 240v I’m using #10 THHN, my question is can I use a #12 ground?

Take a look at table 250.122 . If you have a 25A breaker, you must use a #10 ground. Other factors might require you to use an even larger ground, but you wouldn't be able to go smaller.


(from https://www.mikeholt.com/files/PDF/20_BG_250.122.pdf )

 

[Rsemp]

Disregard, I found my answer. Thanks

 

[infinity]

Disregard, I found my answer. Thanks

So what size did you come up with?

 

[don_resqcapt19]

If you are using 10AWG circuit conductors for a circuit with an OCPD of 30 amps or less, you must used a 10AWG EGC.

 

[Deltaforce]

Other factors might require you to use an even larger ground,

EGC size no require larger than circuit conductor size 250.122A

 

[don_resqcapt19]

EGC size no require larger than circuit conductor size 250.122A

Correct, but if you use a 1/0 circuit conductor for a 15 amp circuit, the EGC is required to be 1/0.

 

[winnie]

EGC size no require larger than circuit conductor size 250.122A

That is a good point. I was mentioning 250.122 as a minimum size and wanted to make it clear that there were other rules that could increase the size of the EGC. However there are a few corner cases where the allowed phase conductors may be smaller than table 250.122

 

[Deltaforce]

few corner cases where the allowed phase conductors may be smaller than table 250.122

Parallel conductors case?

 

[winnie]

I was thinking motor or HVAC loads where you might see a 30A breaker protecting 12 ga conductors

 

[Deltaforce]

I was thinking motor or HVAC loads where you might see a 30A breaker protecting 12 ga conductors

250.122A still apply. EGC size need no exceed 12awg

 

[infinity]

Parallel conductors case?

Sort of. The EGC may be required to be larger than the individual parallel phase conductors.

 

[winnie]

250.122A still apply. EGC size need no exceed 12awg

I'm not arguing with you. I pointed out the general table, you pointed out the exception to the table, I agreed with you. You asked if I was thinking about large parallel installations, I said I was thinking about motor and HVAC installations.

 

[infinity]

Also the EGC for tap conductors is based on the OCPD ahead of the tap so that EGC may be required to be larger than the tap conductors.

 

[Dennis Alwon]

Also the EGC for tap conductors is based on the OCPD ahead of the tap so that EGC may be required to be larger than the tap conductors.

I didn't know that. I assumed the smaller taps were enough to trip the breaker then the smaller equipment grounding conductor would also work.

 

[Deltaforce]

I'm not arguing with you. I pointed out the general table, you pointed out the exception to the table, I agreed with you. You asked if I was thinking about large parallel installations, I said I was thinking about motor and HVAC installations.

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