Nec 250.122

[cirelo132]

Hey guys,

I am having a disagreement with a coworker over how to read NEC 250.122, about the Size of Equipment Grounding Conductors.

I think that for a 110 Amp breaker, the equipment grounding conductor should be #6 AWG Copper, because the 110 A breaker means we should use the 200 Amps line in Table 250.122.

My coworker thinks that for a 110 Amp Breaker, the equipment grounding conductor should be #8 AWG Copper, because the 110 A breaker means we should use the 100 Amps line in Table 250.122.

Can someone let me know which one of us is correct? How is the table read?

 

[C3PO]

Look at the description on the left column it says:

Rating or Setting of Automatic Overcurrent Device in Circuit,etc.,
Not Exceeding (Amperes)

 

[Dennis Alwon]

Hey guys,

I am having a disagreement with a coworker over how to read NEC 250.122, about the Size of Equipment Grounding Conductors.

I think that for a 110 Amp breaker, the equipment grounding conductor should be #6 AWG Copper, because the 110 A breaker means we should use the 200 Amps line in Table 250.122.

My coworker thinks that for a 110 Amp Breaker, the equipment grounding conductor should be #8 AWG Copper, because the 110 A breaker means we should use the 100 Amps line in Table 250.122.

Can someone let me know which one of us is correct? How is the table read?

You are correct. #8 copper is good from 70-100 amps. Greater than 100 you need #6 til you get to 200 amps.