transfer switch

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bsh

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I have a running "discussion" about the need for a disconnect for the service conductors that are connected to a transfer switch then the main switchgear which provides the disconnect for the building. I say that the transfer switch needs to be "sevice entrance rated" (and has a built-in main disconnect) or a service disconnect is required. He says that the main disconnect in the building switchgear is the "service disconnect". Who is right?
 
IMHO there needs to be a disconnecting means ahead of the ATS (service disconnect) if the whole system will be on optional standby power. If only a panel or two then maybe not.
 
As I see it, if the ATS is the first point of entry it needs to either be SUSE labeled or needs another SUSE disconnect in front of it. That has been my experience with AHJs as well.

A possible exception might be if the ATS were made of circuit breakers that could be manually disconnected, assuming there would be 4 or fewer mains behind it (6 hand rule), but as far as I know, all of the ATS units made with breakers are SUSE labeled anyway.
 
bsh said:
I say that the transfer switch needs to be "sevice entrance rated" (and has a built-in main disconnect) or a service disconnect is required. He says that the main disconnect in the building switchgear is the "service disconnect". Who is right?
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You are. It may not necessarily have to be fused or be a breaker, but it must be the first equipment after the meter.

Added: Have your guy read 230.82 ('02 NEC).
 
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LarryFine said:
You are. It may not necessarily have to be fused or be a breaker, but it must be the first equipment after the meter.

Added: Have your guy read 230.82 ('02 NEC).
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But don't forget about 230.91 if the service disconnect doesn't have the OCP as an integral item. And also 230.94. And the one about the distance limit on running service conductors into the building.

Not having the OCP in the service disconnect may be allowed, but I can't think of any situations when I would be comfortable doing that.

Steve
 
If the transfer switch is installed ahead of the original (existing) service, then it will have to be rated as suitable for service equipment and it will become the service disconnecting means. If there is a disconnecting means installed ahead of the transfer switch, than the transfer swith is not the service disconnect.
 
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