I have one metered service feeding two 100 amp panels separately one to the house then one to the garage. Can I install a 22kw generator and use one transfer switch for both 100 amp panels?

  • 1
    Depends what you mean by "transfer switch". Do you mean one of those janky overpriced things that hooks to your panel and lets you switch 6, 8 or 10 circuits one at a time? Or do you mean a big 3-pole double-throw knife switch type thing? Sep 14, 2020 at 17:20

1 Answer 1


The answer is yes you can install a 200 amp transfer switch to feed the 2 100 amp panels.

The possible issue becomes code requires the generator to be large enough to handle the load transferred. Your generator being 22kw will probably be fine however the total load transferred may exceed the 91.6 amps of capacity.

An example of this being electric oven drawing 40 amps , electric dryer drawing 20+ amps the water heater drawing 20 amps and now add some lights or a well pump A refrigerator, freezer and the generator could be maxed out.

I usually suggest manual (much cheaper transfer switches) this allows you to turn off the dryer Breaker and something else so the refrigerator/ freezers Can run without over loading the system.

22kw will probably be large enough to run your home and garage but if not large enough some load shedding is required and a mechanical transfer switch would be my recommendation.

  • I assume you've seen a lot of these setups... how do you figure the two 100A cables are attached to the meter now? Double-lugs that support 100A cables, or single lug that supports 200A cable and then Polaris to split? I'm concerned about getting from the meter to the Xfer switch without paralleling. Sep 14, 2020 at 17:28
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    Double lug or 2 separate breakers are quite common my current home has this exact setup on a 200 amp main one feed to the garage,shop, barn then house. My last home had twin 200 feeds so yes it is a common method. The transfer switch is usually put below or beside the meter the switch has to have the service rating. With a manual switch some loads can be turned off and still meet code. With an auto switch the generator must be able to handle the transferred load so this takes some measurements to verify the generator can handle normal loads. Magnetic contactors can be added to drop large loads
    – Ed Beal
    Sep 14, 2020 at 17:40

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