Tap rules for ground wire?

[steve66]

Brain freeze here: Can the tap rules apply to the ground wire too? I think not, but I wanted to verify.

Say for example, I have a 1600 amp breaker feeding a bus. I'm going to tap the bus and run (2) sets of 350KCM wire to a 600 amp breaker (25' tap rule). Does the ground wire ran with the tap need sized for the 1600 amp breaker? If so it would be (2) 4/0 wires. Does that sound right? Or can it be (2) #1's?

Steve

 

[jumper]

I think the EGC for the tap may be based on the 1600 amp breaker.

250.122

(G) Feeder Taps. Equipment grounding conductors run
with feeder taps shall not be smaller than shown in Table
250.122 based on the rating of the overcurrent device ahead
of the feeder but shall not be required to be larger than the
tap conductors.

 

[Smart $]

Does the ground wire ran with the tap need sized for the 1600 amp breaker? If so it would be (2) 4/0 wires. Does that sound right? Or can it be (2) #1's?

Yep... (2) 4/0.

 

[petersonra]

If you are using a wire as an EGC in a branch circuit, the minimum EGC size is based on the size of the OCPD protecting the branch circuit.

 

[steve66]

I think the EGC for the tap may be based on the 1600 amp breaker.

250.122

(G) Feeder Taps. Equipment grounding conductors run
with feeder taps shall not be smaller than shown in Table
250.122 based on the rating of the overcurrent device ahead
of the feeder but shall not be required to be larger than the
tap conductors.

Its hard to argue with that.

Thanks: Steve