housemoney
Member
- Location
- Midwest
- Occupation
- Engr
My service entrance is an ATS with a 2500A LSIG main breaker with an ERMS switch. The genset has a 2000A LSIG main breaker with NO ERMS switch. There are 2 MCC feeder breakers (both LSIG) in the switchboard that can be set to 1200A that have NO ERMS switch.
The way I interpret 2017 NEC: 240.87 is that ALL breakers capable of being set to 1200A or greater require an ERMS switch. Which would include the 2000A gen breaker and 2- 1200A MCC feeder breakers I mentioned above?
I don't see an exception for omitting an ERMS switch downstream, when an upstream breaker has ERMS switch protection- similar to upstream ground fault protection in 215.10 EX 2?
Thanks for the sanity check!
The way I interpret 2017 NEC: 240.87 is that ALL breakers capable of being set to 1200A or greater require an ERMS switch. Which would include the 2000A gen breaker and 2- 1200A MCC feeder breakers I mentioned above?
I don't see an exception for omitting an ERMS switch downstream, when an upstream breaker has ERMS switch protection- similar to upstream ground fault protection in 215.10 EX 2?
Thanks for the sanity check!
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