Can you always downsize the equipment grounding conductor?

[zappy]

So you have a 30 amp 220 circuit. 10 gauge wire can you pull a 12 gauge wire for the ground? When is it allowed and not allowed? Thank you for your help.

 

[peter d]

You still need a #10 in that situation. Look at the EGC chart, 250.126. (I think!)

 

[infinity]

Table 250.122.

 

[Strathead]

So you have a 30 amp 220 circuit. 10 gauge wire can you pull a 12 gauge wire for the ground? When is it allowed and not allowed? Thank you for your help.

It isn't allowed and people do it all the time.

 

[zappy]

We were pulling 8-3 MC cable and 6-3 MC cable both of them the ground was one size smaller they were for vent fans on the roof 480 V.

 

[iwire]

We were pulling 8-3 MC cable and 6-3 MC cable both of them the ground was one size smaller they were for vent fans on the roof 480 V.

You need to look at table 250.122

But with 15, 20 & 30 amp circuits the EGC has to be at least the same size as the circuit conductor.

Once you get above 30 amp circuits the EGC is smaller than the circuit conductors.

10 AWG for 31 to 60 amp circuits, 8 AWG for 61 to 100 amp circuits etc.