standby generator disconnects

[thndrbird71]

I recently put in a bid for a city job of installing an automatic standby generator for their well house...... a 400 amp 240 volt three phase service.

In my quote i figured a price for installing an outside manually operated disconnect to be mounted between the generator and the automatic transfer switch ( which is located on the outside of the well house in a custom made metal cabinet, as the city ordered an interior transfer switch, but no viable room inside to mount it).

My question is this, is the manually operated disconnect needed for such an installation?
Thank You.

 

[buddhakii]

If the breaker on the generator or the transfer switch is not service rated then you will need a service rated disconnect coming off the generator.

 

[hrlyman]

See Code Section 700 for all your information; There is no requirement for a disconnect between the transfer switch and the generator. A "Bypass Isolation" switch is permitted but not required - See 700.6(B).

The transfer switch has to allow unimpeded progress of gen power back to the emergency system circuits when the utility source is down. A disconect between it and the gen could impede that.

Good luck on your project

 

[ceb58]

See Code Section 700 for all your information; There is no requirement for a disconnect between the transfer switch and the generator. A "Bypass Isolation" switch is permitted but not required - See 700.6(B).

The transfer switch has to allow unimpeded progress of gen power back to the emergency system circuits when the utility source is down. A disconect between it and the gen could impede that.

Good luck on your project

Do what?
The requirements are 225.31, 225.32. 225.36 and 445.18. The installation the OP describes would more than likely fall under 701. And even though the wording is the same for bypass isolation it has nothing to do with the requirements of a disconnect.
The only way a disconnect would not be needed is the ATS is service rated with built in disconnects or the breaker on the gen. set is within site and would have to meet 225.36 and 445.18 which unless specially ordered it would probably not meet the requirements