standby generator ground fault protection

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wyboy

Senior Member
I have an optional standby generator servicing a structure. It is 1500 amps, 480/277. NEC 700.27, 701.27 (emergency systems and required standby) allow ground fault indication but Article 702 has no exception to the ground fault protection requirement for an optional standby generator so ground fault protection must be installed, correct?
 

publicgood

Senior Member
Location
WI, USA
Ground fault must be installed as required for feeder/service, no matter. 700/701 allows alarm only. 702 requires trip on ground fault.
 
Location
Chicago
The issue of ground fault protection is addressed in NEC Article 700 for emergency generators and in Article 701 for legally required standby generators but there is nothing about ground fault protection in Article 702 for optional standby generators. My question is related to optional standby generator systems.

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pv_n00b

Senior Member
Location
CA, USA
I have an optional standby generator servicing a structure. It is 1500 amps, 480/277. NEC 700.27, 701.27 (emergency systems and required standby) allow ground fault indication but Article 702 has no exception to the ground fault protection requirement for an optional standby generator so ground fault protection must be installed, correct?

You are correct. Since 700 and 701 can deal with systems that are life safety they are allowed to continue to operate with a ground fault condition. Art 702 systems have to trip on ground fault.
 

publicgood

Senior Member
Location
WI, USA
I have an optional standby generator servicing a structure. It is 1500 amps, 480/277. NEC 700.27, 701.27 (emergency systems and required standby) allow ground fault indication but Article 702 has no exception to the ground fault protection requirement for an optional standby generator so ground fault protection must be installed, correct?

Correct. Additionally, you may want a second CT lead for the generator controller ground fault relay.
 
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