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I currently have a portable generator, an inlet, and an interlock on the main panel to backfeed the panel.

I am moving over to an automatic transfer switch with a standby generator. However, as a backup, I am keeping my portable generator and inlet.

I would like to eliminate the interlock and bring the wires from the inlet in through the automatic transfer switch in the same way that the standby generator connects to it, and select which generator I want to use by way of a DPDT safety switch -- I already own this one.

However, the only circuit breaker that would be sized to protect the wires between the inlet and main panel (through the ATS and safety switch) would be the circuit breaker inside the generator.

Is that allowable by code? Or do I need to put in a hard-wired single-circuit breaker panel before the safety switch to protect the wires?

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    Will the smaller generator start automatically? I'm just confused of what you stand to gain. Worst case inline fuse boxes are not that expensive and come with a free shutoff switch. They are used in hot tubs etc. Apr 5, 2018 at 21:35
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    @Harper The automatic transfer switch supports load shedding, etc. Since this is a backup to the standby generator, I would like to be able to maintain the same load shedding capabilities if I have to switch to the backup. At 10 running kW/12 kW surge, my portable generator is plenty big enough to handle most of the loads in the house if properly managed by load-shedding. As opposed to right now, where using the standby generator does require having to manage the various loads on my own. It makes sense to use the functionality of the ATS with the portable, manual generator. Apr 7, 2018 at 16:07
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    @ArchonOSX I didn't discuss this in the original question because it isn't part of the original question. Rather than answering the original question, you're discussing something unrelated. However, yes, Dynamic Load Shedding is the Generac brand name for Load Management. There is no additional panel. It dynamically peels off larger circuits that are wired through special modules interactively to ensure that the generator's total capacity is not exceeded, which makes it comply with code. Dec 6, 2019 at 19:19
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    It's a shame this never got a good answer, I think it's a good question. If it's possible to connect a generator too big for said wires then they should certainly have a fixed breaker. But if they are protected by the generator's breakers and a suitably sized inlet, perhaps code allows no fixed breakers. Good question. It's been a couple of years, what did you do?
    – jay613
    Nov 22, 2021 at 12:42
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    Also I think people are confused by the question. At the point you are using this you don't have a full ATS. You have the backfeed protection and load shed components of an ATS combined with an MTS to switch input power. No ATS at all. And you have the feed wire from the generator to the MTS protected only by the generator's integrated breakers. Is that ok? That is the question. I think actually that is the typical arrangement.
    – jay613
    Nov 22, 2021 at 12:45

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How about putting the automatic interlock upstream of the interlocked panel you already have?

If that is your main panel you could side-grade it to a sub panel and put a main breaker upstream of the auto-switch.

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    The automatic transfer switch already will be upstream of the panel. It includes a 200A service rated main breaker. The goal here is to eliminate the interlock at the panel and instead bring the inlet in through the ATS as well. Apr 5, 2018 at 20:10

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