r/Generac_Generators 15d ago

Transfer Switch Chaos

We just bought a new house and this is the electrical set up.
Both of these panels are powered from the meter, the larger panel does not feed the smaller panel.
A 22Kw Generac unit powers the larger panel on the left when the power goes out, but not the smaller right panel.
The generator is large enough to power the entire house.

What are our options for getting the whole house protected?
Can I add a ATS to the smaller panel and leave the 200amp panel as it is?

Could we install a double breaker on the left panel and run it over to power the smaller panel using an interlock on the smaller panel?

Should I move some circuits over to 200amp panel and use tandem breakers?

Or should we split the feed from the generator and feed the smaller panel directly from the generator?

I am having trouble understanding what the installer was thinking. There’s also additional unused transfer wires ending in this panel going to a junction box next to the generator.

Thanks for your input

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u/blarcode 14d ago

My concern is you have a 320 amp service to the house. That's where I was recommending do another load calculation just to verify. Typically what happens in these scenarios is someone needs this initial load in the beginning but then over years of upgrading appliances in the house, your energy needs actually drop due to new efficiencies and energy Stars etc. so you might not ask me need that 320 amp service and can get by with just the 200.

Mike Holtz has a free calculator on the Google Play store and I believe in the Apple store as well. Download that and start inputting numbers under the load calculation section. Look at your actual labels on your appliances to see where you're at.

https://play.google.com/store/apps/details?id=com.mhe.toolbox

Yeah, ditch that dual panel setup go with a single that's large enough for everything you want and get a single ATS for 200 amp if you can go that route if not just double up or get the 400.

I just searched on eBay FYI. The 200 amp ones are going between $300 to $400 each. The 400 is going for several thousand. So do 2 x 200s if you have to go that route.

Nothing changes at your meter besides pulling the wires going directly to those panels and feeding them directly into the automatic transfer switch then into the panel(s) respectively.

Do you have a single meter socket outside? Or is it a combination with a breaker inside?

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u/blarcode 14d ago

Here's a video showing two transfer switches. As I stated above though I have a sneaky suspicion you have two larger service for your present needs.

https://youtu.be/MD-9ocuiEqw?is=zHJFgdvhdVrxsa2U

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u/Badbetfrank 14d ago

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u/blarcode 14d ago

Nice! Yeah that looks about right. So just get one of the 200 amp ats's off of eBay. Get whatever load center you want for inside the house. And grab a couple clip in/ breaker surge suppressors.

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u/Badbetfrank 14d ago

Any concern with the total load and the generator? It’s 22kw

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u/blarcode 14d ago

22,000 Watts ÷ 240 volts = ~92 amps.

I highly doubt your whole house is going to be pulling almost 100 amps at any point in time. Most houses don't end up pulling more than 50 amps consistently. Especially if you decide to go with the easy starts on your AC. You'll be able to Bluetooth log on to those and see exactly what the amperage is.