standby generator

[Thomas Valdez]

Does the ATS require a Main breaker or switch from the utilty service? The generator shall be sized for the whole service. There is a main breaker in the main panel. Is it allowed to go directly from utility service to ATS, then to main breaker in main panel. Service is 800 A 277/48o

 

[RUWired]

Thomas, The requirement is to have the OCPD protect all circuits and devices per 230.94.Welcome to the forum!!

Rick

 

[ceb58]

Does the ATS require a Main breaker or switch from the utilty service? The generator shall be sized for the whole service. There is a main breaker in the main panel. Is it allowed to go directly from utility service to ATS, then to main breaker in main panel. Service is 800 A 277/48o

The ATS must be service rated (built in breaker) or a disconnect must be between the meter and ATS.
The generator must be sized to the transfered load.

 

[tom baker]

There are ATS that are service entrance rated with no overcurrent protection. But watch the maximum available short circuit current.
I don't like that type of ATS as there is no way to turn off the power to work on it. I've installed some CH ATS that have fuses on the service and generator inputs. Handy where the generator is larger than the service.