Voltage drop and grounding

[sevlander]

Is it neccesary to increase the ground size when voltage drop requires circuit wires to be increased? If so how do you size the equipment ground for a 20 amp circuit that has been sized at #6 thhn for V.D.?

 

[raider1]

Yes, take a look at 250.122(B).

You would upsize the EGC proportionately according to the circular mil area of the ungrounded conductors.

Chris

P.S. there is a debate going on about this very topic HERE

 

[charlie b]

. . . how do you size the equipment ground for a 20 amp circuit that has been sized at #6 thhn for V.D.?

Actually, that's an easy one to figure out. For a 20 amp circuit, the ungrounded conductors and the equipment grounding conductor are the same size (i.e., #12). When you increase the size of the ungrounded conductors, all you have to do to "increase the EGC proportionally" is to, once again, match the size of the EGC to the size of the ungrounded conductors. In your example, you need the EGC to be size 6.

This works the same way for a 30 amp circuit, since the ungrounded conductors and the EGC are once again the same size (i.e., #10).

 

[Pierre C Belarge]

This is a common question and issue for parking lot pole lights. A 20 amp ckt that is installed with 6Awg phase conductors. Most times, the contractor will install 10 Awg EGC, when it should be a 6 Awg EGC, by Code that is. Read the other thread and you will see that some question the size of the EGC. As of now that is the code.