Sizing Conductors for a Transfer Switch

[Little Bill]

Let's say you have a 200A service and are using 2/0 cu conductors. You have a 200A service rated transfer switch. You run the 2/0 from the meter to the TS, and 2/0 to the panel from the TS. Now the generator is only around 80A. Do you have to run the same size (2/0) conductors from the generator to the TS? Or do you size them for the 80A?

 

[LarryFine]

Do you have to run the same size (2/0) conductors from the generator to the TS? Or do you size them for the 80A?

The latter; size to suit the genny output breaker.

 

[Little Bill]

The latter; size to suit the genny output breaker.

Thanks!

 

[kwired]

Although if the generator had 200 amp breaker, you should be able to use 2/0 if it is only supplying the dwelling.

 

[don_resqcapt19]

If the transfer switch is automatic, the generator must be sized to serve the total connected load or have load shedding devices to limit the load to the output of the generator.