Sub Panel with no EGC

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PowerdT

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San Diego
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Electrical Engineer
I have 225A, 3phase sub panel with no EGC. I can’t find on a code but can I create ground inside panel for branch circuit instead of using EMT?
 
Are you saying the feeder to the panel is EMT?
 
PowerdT said:
Yes the feeder is using EMT so all the branch circuit use the EMT as well as EGC
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So you do have an EGC and I wouldn't worry about it. In most cases metallic conduit or tubing in metal construction is a superior EGC than a wire.
 
PowerdT said:
I can’t find on a code but can I create ground inside panel for branch circuit instead of using EMT?
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Short answer no. You cannot bond the neutral to create an EGC in a sub-panel. As others have noted you do have an EGC run with the feeder in the metallic tubing so that is all that is required.
 
infinity said:
Short answer no. You cannot bond the neutral to create an EGC in a sub-panel. As others have noted you do have an EGC run with the feeder in the metallic tubing so that is all that is required.
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The reason I mentioned is because I have seen some panels in commercials building with no EGC feeder, but they have green wire bonded to the EMT knockout then to ground busbar inside panel
 
PowerdT said:
The reason I mentioned is because I have seen some panels in commercials building with no EGC feeder, but they have green wire bonded to the EMT knockout then to ground busbar inside panel
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A bonding jumper (the green wire) from a bonding bushing is required if the voltage is over 250 volts to ground and if the panel has concentric or eccentric knock outs. Some guys just like them on everything even when they're not required.
PowerdT said:
What size of EGC wire shall be used to bond? Would that be 250.122 based on 225A #4
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It would be sized according to T250.122 or larger if 250.122(B) comes into play with the feeder.
 
PowerdT said:
I see if ground busbar inside enclose is bolted to enclosure no need to bond anything. For example, if I have a lighting load to feed I can use 2#12 and 1#12G
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Yes, if I understand you correctly. A grounding bus bolted to the can effectively connects the grounding wires to the feeder conduit.
 
You are talking about adding circuits to this panel, am I correct? You can use a grounding conductor and just bond it to the enclosure. I've even added a grounding conductor buss into a panel and just bonded it to the enclosure
 
LarryFine said:
Yes, if I understand you correctly. A grounding bus bolted to the can effectively connects the grounding wires to the feeder conduit
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To be clear of the plan, I’m replacing the 480V 225A panel and re-routings all the branch circuits. The panel feeder is only 3 hot and 1 neutral, EMT used as EGC.

Even tho EMT is acceptable as EGC and the branch circuits also used the EMT as EGC,. I was in Impression to add #12 to each circuit since the route of the branch circuit is long
 
PowerdT said:
To be clear of the plan, I’m replacing the 480V 225A panel and re-routings all the branch circuits. The panel feeder is only 3 hot and 1 neutral, EMT used as EGC.

Even tho EMT is acceptable as EGC and the branch circuits also used the EMT as EGC,. I was in Impression to add #12 to each circuit since the route of the branch circuit is long
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The calculations will say that the EMT is an effective ground fault path for a longer distance than a wire type EGC that has been sized per Table 250.122.
 
Does the enclosure of the new panel have concentric or eccentric knockouts that you will be using? If it does, are those knockouts "listed to provide a reliable bonding connection"? (250.97)
 
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