Generac transfer switch

[elkappyton]

I'm going to be installing a generator in a home that has two outdoor 150A disconnects feeding two panels in the house. If I was to put the transfer switch before the two main service disconnects, does it have to be a 300A disconnect. If so its seems more cost effective to replace the two existing 150A disconnects with two transfer switches.

 

[LarryFine]

If I was to put the transfer switch before the two main service disconnects, does it have to be a 300A disconnect. If so its seems more cost effective to replace the two existing 150A disconnects with two transfer switches.

Welcome to the forum.

You could use a single 300a ATS, but you're already wired for two, and yes, doing two is probably cheaper. It's certainly easier.

You can either replace the existing discos with service-rated ATSs or wire in either type of ATS after each of the existing discos.

The best part of having exterior discos is that the feeders and panels are already wired as sub-panels, saving you a lot of work.