Transfer switch/ meter base rating

[nizak]

Does a service rated automatic transfer switch used in conjunction with a stand by generator have to have an amperage rating equal to or in excess of the meter base? I need to use a 320A meter base in order to get the double lugs that I need to supply both the house panel and an out building panel.The outbuilding will feed off the load side of the meter on a separate set of lugs(does not require standby power) and the ATS will feed off the load side on it's own set of lugs. My total load will most likely never exceed 150A (house and building combined) but cannot use a 200A socket because of the lug arrangement. I am being told by the generator supplier that both units (meter and switch) have to have compatible amperage ratings, I disagree. Any input appreciated.

 

[augie47]

There is no reason for the ratings to match. The ATS needs conductors suitable for the main breaker. The meter base needs to be sized for the total load connected.

 

[fmtjfw]

The laws of physics do not agree with the manufacturer. The fault current available for the service-side lugs of the ATS are not materially different no matter what meter socket you use. The load on the generator-side and the load-side lugs of the ATS are determined by the generator and by the OCPD of the loads.

I guess that they are worried that someone will "upgrade" the service without upgrading the ATS.

 

[electrofelon]

Does a service rated automatic transfer switch used in conjunction with a stand by generator have to have an amperage rating equal to or in excess of the meter base? I need to use a 320A meter base in order to get the double lugs that I need to supply both the house panel and an out building panel.The outbuilding will feed off the load side of the meter on a separate set of lugs(does not require standby power) and the ATS will feed off the load side on it's own set of lugs. My total load will most likely never exceed 150A (house and building combined) but cannot use a 200A socket because of the lug arrangement. I am being told by the generator supplier that both units (meter and switch) have to have compatible amperage ratings, I disagree. Any input appreciated.

Is this a 230.40 EX#3 install? FWIW, although the 320 meter base may well be the simplest cleanest way to do it, you could always use a 200 amp socket and just tap /splice in a box next to it. Definitely counter code about the ATS having to have equal/greater rating.....