AmazingTrans
Member
- Location
- Australia
Hi there!
I have two different control enclosure (Cabinet A & Cabinet B) that has their individual disconnect but they are side by side. Cabinet A has a 600 Amps Circuit breaker, and Cabinet B has 400Amps Circuit breakers that is powered by a transformer that is powered by Cabinet A. Currently, I have a bond wire from cabinet A ground to cabinet B size according to the FLA of cabinet B.
In cabinet B, there is other storage energy devices such as caps and the ampacity in the cabinet can run as high as 900Amps+ running 700VDC).
My question here is:
1) I have been reading the NEC book and noticed there is two tables, one is table 250.122 Minimum Size Equipment Grounding Conductors and another is Table 250.66 Grounding Electrode Conductor for Alternating-Current Systems. Which table do I follow to size the bond jumper wire between cabinet B to cabinet A ground lugs? And when I size the ground jumper wire, do i size according to the Ampacity of the FLA in cabinet B, or the largest ampacity of current of the storage devices ?
2) The current in cabinet B is larger than the incoming current going into cabinet A due to storage energy devices. Would the incoming power line going into cabinet A should have ground/PE size according to cabinet B or just size according to FLA of cabinet A consumption?
3) Would I need to have a separate PE pull into Cabinet B since it has larger ampacity?
Hope to hear from the experts!
I have two different control enclosure (Cabinet A & Cabinet B) that has their individual disconnect but they are side by side. Cabinet A has a 600 Amps Circuit breaker, and Cabinet B has 400Amps Circuit breakers that is powered by a transformer that is powered by Cabinet A. Currently, I have a bond wire from cabinet A ground to cabinet B size according to the FLA of cabinet B.
In cabinet B, there is other storage energy devices such as caps and the ampacity in the cabinet can run as high as 900Amps+ running 700VDC).
My question here is:
1) I have been reading the NEC book and noticed there is two tables, one is table 250.122 Minimum Size Equipment Grounding Conductors and another is Table 250.66 Grounding Electrode Conductor for Alternating-Current Systems. Which table do I follow to size the bond jumper wire between cabinet B to cabinet A ground lugs? And when I size the ground jumper wire, do i size according to the Ampacity of the FLA in cabinet B, or the largest ampacity of current of the storage devices ?
2) The current in cabinet B is larger than the incoming current going into cabinet A due to storage energy devices. Would the incoming power line going into cabinet A should have ground/PE size according to cabinet B or just size according to FLA of cabinet A consumption?
3) Would I need to have a separate PE pull into Cabinet B since it has larger ampacity?
Hope to hear from the experts!
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