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This is how the 240v well pump at my house is wired. In my part-time DIYer experience, this doesn't seem up to code.

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  • This is in a shed about 80 feet from the main panel.
  • The grey wire is 10/2 UF connected to a dual pole 40 amp breaker in the main panel. (Side note: shouldn't this be a 30 amp breaker?)
  • The red and black wires run to the well's pressure switch

I would like to improve this connection and potentially allow the well pump to be plugged in to a portable generator for emergency use. It seems like the best option would be to terminate the UF wire at a receptacle and then add a plug to the wires running to the pressure switch that can be plugged into this receptacle, or into a generator as needed.

If this is the best approach, what type of receptacle and plug should I use? 6-30 seems like the natural choice for the receptacle based on the wire, but the most common generator receptacle for 240v is L14-30. I assume I'll need some sort of adapter at some point? Or is there a better way to accomplish what I'm looking for?

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    Just a few violations there, yep...
    – Ecnerwal
    Commented Sep 22, 2022 at 17:49
  • Needing a 30 breaker is right. Cannot just connect a generator to a house's circuits, without an isolation switch for the grid, do not want to shock some poor guy up a pole in the rain.
    – crip659
    Commented Sep 22, 2022 at 17:51
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    @crip659 OP is not talking about connecting generator to the house but rather changing the pump to plug/cord to be able to plug it into house or generator. Commented Sep 22, 2022 at 18:00
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    @manassehkatz-Moving2Codidact You are right. Took me a couple of re-reading to understand it right. Have similar hook up for my well, but I switch the wires themselves instead of OPs neater version. One good reason to have it in a shed, instead of in the basement.
    – crip659
    Commented Sep 22, 2022 at 18:42
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    @manassehkatz-Moving2Codidact is correct. I would like to be able to unplug/disconnect the pump from my house wiring and plug it (and only it) into a portable generator. Commented Sep 22, 2022 at 18:49

1 Answer 1

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this doesn't seem up to code.

  • The circuit bypassing the mandatory disconnect.
  • the UF-B cable having zero physical protection e.g. conduit. It needs physical protection down to its 24" burial depth. Once at depth it no longer needs it.
  • Lack of cable clamps at disconnect. (which will become conduit connectors).
  • Presumed similar defects at the other end.
  • Red/black THHN wire in invisible conduit, not approved yet.
  • Safety ground mishandled or absent everywhere (metal conduit will take care of that, though).

(Side note: shouldn't this be a 30 amp breaker?)

Maybe, maybe not. Motor rules are weird.

You need to look at the motor nameplate data. Breakers are there to handle short circuits and overloads. Some motors have onboard overload protection (it can observe motor temperature; breakers can't). If the motor is the only load, the breaker is thus only concerned with short circuits! So some flex is allowed to help avoid nuisance trips from motor startup. That trick only works if the circuit is dedicated to that motor. Once it's shared with other loads, forget it.

I would like to improve this connection and potentially allow the well pump to be plugged in to a portable generator for emergency use. It seems like the best option would be to terminate the UF wire at a receptacle and then add a plug to the wires running to the pressure switch that can be plugged into this receptacle, or into a generator as needed.

Makes sense to me. NEC 400.7 allows that. The cord/plug connection will serve the purpose of the disconnect, so it is no longer required. (but some code violations are still relevant).

However, since anything could be plugged into the plug, that will void the exemption for the "motor rules" and require the breaker to match the socket = 30A breaker.

If this is the best approach, what type of receptacle and plug should I use? 6-30 seems like the natural choice for the receptacle based on the wire, but the most common generator receptacle for 240v is L14-30.

That may well be, but if you install a NEMA 14 or L14 socket, you must supply neutral and ground separately to the socket. So you will need to trench a new conduit or cable from the house. But then, you might need to anyway due to code violations in the current installation.

You must not ever hard-install a NEMA 14 family socket without a neutral. If you do, and someone plugs into it with a thing that needs neutral such as an RV, they'll fry every appliance in the RV.

Even more importantly, you must never attach the neutral of a NEMA 14 socket to ground! That is even more dangerous - while the first case will annoyingly fry appliances, this case will kill people. You can buy new appliances.

So how do you solve that problem? #1 it is perfectly legit to have a cord with a NEMA 6 socket but a NEMA 14 plug. The appliance plugged into that socket doesn't want or need neutral, so it just isn't taken from the NEMA 14 plug. That's fine and UL will approve commercially made adapters like this.

The reverse is not safe and will never be UL approved. If you really need to make one of those, make it 1 foot long. That way it is an obvious "cheater cord", rather than being non-obvious. That will put people on guard against using it. Remember never attach NEMA 14 neutral to ground!

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