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I'm installing an service rated ATS for a breaker that has the critical circuits (lighting, septic, etc.). I wanted to include some non-critical 120v circuits which would drop if the load is too high, however I'm told that the SMM modules can only be used with 240v circuits.

If I have a 12-3 or 14-3 circuit, could I still use these? Technically (if I'm understanding correctly) the two hots are on separate poles and equivalent to 240v. Presumably it would shed both loads?

Any insights would be hugely appreciated.

SMM Manual - https://www.electricgeneratorsdirect.com/manuals/6873 Manual.pdf

Thanks
Dave
 

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From what I can tell all you have there is a contactor(relay) with two sets of contacts. If you only use one set you can control a 120 volt load. Or you can use both sets to control two separate 120 volt loads. Shared neutral would not be a requirement. 240 volts between the hots would also not be a requirement.

A contactor is simply a voltage controlled switch. That contactor with two sets of contacts is just two switches that activate at the same time.
 

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Interesting, thanks. I'll open one up tomorrow (getting them in the mail) and follow the paths to see what the circutary look like.

Both Generac, and the dealer I bought them, were adamant they had to have an input of 240v but others who have installed them seem to have used them for 120v loads.

I'll report back tomorrow!
 

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Upon further review of the wire connections it appears you are probably correct about the 240 volts. It seems connection G & H are power to the PCB and to control the relay which is drawn from the 240 volt A & B line connection.
 

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Upon further review of the wire connections it appears you are probably correct about the 240 volts. It seems connection G & H are power to the PCB and to control the relay which is drawn from the 240 volt A & B line connection.
That’s what I thought also. So presumably a double pole breaker with 2 hots would work but ultimately shed both circuits?
 
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