we are building a new steel facility with a 400A 208 3-ph service It cconsists of (1) CT cabinet and (2)200 Main Bkr Panels. The service entrance conductors from the parallel lugs of CT cabinet are (2) sets of 3/0 AWG, with full neutrals. I understand 250.66 typically requires at least a #1/0 for the GEC on a 400A service, and that when parallel feeders are used, the sum of their equivalent areas is used. However, since we have two 200 A main bkr panels, are these still considered parallel feeders. Am I correct to say that a #4 from each panel N to bldg. steel would suffice? NOTE: Assuming Bldg.steel is sufficiently bonded to water pipes, and a supplemental driven ground is used outside at CT Cabinet.
Grounding Electrode Conductor
- Thread starter dball
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- Lockport, IL
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- Retired Electrical Engineer
Re: Grounding Electrode Conductor
Two wires are ?in parallel? only if they are connected at both ends. If two sets of 3/0 originate at the same CT cabinet, but travel to separate panels, then they are not in parallel. I think you have two service panels, and that a #4 is good enough for each.
Two wires are ?in parallel? only if they are connected at both ends. If two sets of 3/0 originate at the same CT cabinet, but travel to separate panels, then they are not in parallel. I think you have two service panels, and that a #4 is good enough for each.
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