So i have a Diesel Generator on trailer, which able to run at 1 phase 120/240 or 3 phase 208/240/480. And also i have a house that need 100 amps to run the 4 A/C all together. Which is way over the single 14-50 plug can handle. And forget about interlock part, can I wire two plug into the panel, each using a 2 pole-50amp breaker, and using 2 50amp generator cord to run from generator to house to make the connection? Or maybe even 3 plug to do that? THanks. If this is incorrect, what is the correct way to do so? Please consider this is not a permanent installation, which the generator will be moved away after poweroutage.
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3Make/model of the generator?– manassehkatz-Moving 2 CodidactCommented Jul 11 at 23:15
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3What receptacles/outlets does the generator have(size, numbers)? The interlock is to protect the linesmen fixing the power lines from being killed by your/others generator/s.– crip659Commented Jul 11 at 23:22
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A single 14-50 receptacle/outlet on the generator can only provide 50 amps at the most, really maybe a bit over 40 amps for hours of use, safely. You need at least two 14-50 plugs/outlets on the generator, for the four AC units, ran at the same time. Smart generator use is to limit the amount of power used/needed at one time, or get a bigger generator(whole house type).– crip659Commented Jul 11 at 23:52
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2 Answers
No I don't think you can do that, each inlet needs an interlock or transfer switch,
so to run three cables you need 3 panels (each with interlock) or transfer switches. or a combination of panels and transfer switches.
Perhaps you can put the ACs on transfer switches and the remainder of the panel on an interlock.
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+1 but ... Assuming this generator has three 14-50 outlets with balanced capacity (a tall assumption) will three 50A patch cords, 3 inlets, 2 or three transfer switches, cost less than a whole house ATS?– jay613Commented Jul 12 at 1:30
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Your removed comment had (I thought) a good point. Though our guessing the generator capabilities should probably not go much further. :)– jay613Commented Jul 12 at 1:45
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2could be tricky if the generator cant put 100A onto a single phase. and the question suggest that it is a 3 phase generator with 3 50A outlets. perhaps a transfer switch can convert the house to hot leg delta and run the ACs on the hotleg sides.– JasenCommented Jul 12 at 1:45
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Anyway your first point, which is "no" is certainly correct if we're paralleling different phases 8-0– jay613Commented Jul 12 at 1:46
You cannot run 2 lines off the generator and parallel them into your panel. Not allowed.
What you can do is have multiple subpanels or loads, each with its own inlet, and each with an generator interlock / 3PDT switch wired with the subpanel load on the common, and selects between utility or inlet.
Neutral must be switched. With one exception: ONE panel or circuit is allowed to have neutral not switched. Only one. Only one.
By amazing good luck, the vast majority of A/C units do not use neutral for anything at all. Which saves you the considerable hassle and cost of finding 3PDT neutral-switching interlocks or switches: neutral simply is not involved at all, so you don't have to switch it, and can use common "hot-only switching" transfer kit. For instance a large DPDT switch, or a 4-space Square D "QO" subpanel with 4 breaker spaces right next to each other, and then their QO2DTI interlock.
Place your ONE "inlet that does not switch neutral" onto your general 120/240V subpanel.
One more thing. If you are setting up the loads as 240V 3-phase delta, especially "wild-leg delta" or "stinger-leg" etc., several restrictions come up due to the wild leg being 208V from neutral and ground. First, breakers and switches involved are not allowed to be "Slash" types, aka 120/240V, which are only rated for 120V to ground.
Second, the "wild leg" must use orange wire or wire taped with orange tape or shrink tube.
answered Jul 15 at 2:07
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