Transfer switch

[orezok]

I am looking at putting a 10 to 12KW standby generator with an automatic transfer switch. Does the transfer switch have to be rated for the panel rating (200a) or the generator rating (50a) although realistically a 100a switch?

 

[ronjhall]

If you have 200a service you will need a 200a transfer switch for a whole house setup. You can go smaller if you plan on only supplying some circuits.

 

[tnmike]

Most of the automatic transfer switches are whole house. You would need to size the switch to the panel. Manual switches tend to be smaller and you have to pick out your circuits with critical loads. The generator must be of sufficient size to carry the load.

 

[Truro411]

The two Generacs I installed at work a few years back had an 8 or 10 slot breaker panel built into them. They were 50A switches for 10Kw LPG gensets.

The idea is to feed the switch from your main panel with a 50A breaker and move you essentials to breakers in the xfer switch itself (essentially a subpanel) - fridge, pump, lights, ac, etc. When the power goes out the xfer switch flips from house feed to generator automatically and then back after house power returns. I'd consider this safer than feeding a 200A switch into your 200A panel - safer for the genset that is. A 200A panel is going to require a far larger genset than 10-12kw to carry the load in that panel.