Wiring for Submersible Well Pump (2023 Update)

[John Sheehy]

I am going to try to wire a supply line for a submersible well pump. I talked to the contract who will be installing the well and he said the pump will need 220V. He also said that I should use12/2 romex.

I was under the impression that it is either 120V or 240V, the only difference between the two is that the 240 had 2 120V hot wires going into it. Is this the case, or is a 240 and a 220 the same thing? Also, will one

12/2 romex cable be enough? I've read that you cannot run romex in a pvc conduit. I want to run it underground for about a 10-15 foot run, so what should I use? Thanks in advance for all your help.

[zxcvbob]

220V and 240V are the same thing.

If you run underground feeder cable (type UF romex),you won't need a conduit. Just make sure you bury it deep enough.

You might want to run 12/3 instead of 12/2 so you would have an unused neutral wire if you ever want to install a light out there. (Yes, I know the pump should be on a dedicated circuit. But if there's a neutral wire, you can tap one leg for a light and maybe even tap the other leg for a convenience outlet and just don't tell anybody)

-Bob

[Curmudgeon]

Can't tell you what code is, but my deep well submersible pump does not use Romex....it uses #10 individual wires from the pump switch on down. These are wrapped & taped around the flexible pvc water pipe with plastic "standoffs" every 20 ft. or so to keep the wires from rubbing on the well casing.

[Toller]

220 is an incorrect way of saying 240.

One cable is enough. Whether 12 or /2 are enough depends on the pump and how long the run is from the breaker box. You should err on the side of bigger wire; it will prolong the motor's life.

Sometimes you are required to run romex in conduit, but only for short distances to give it physical protection. Done properly, you shouldn't need the conduit.

[John Sheehy]

[zxcvbob]

The pump only needs two hots and a ground (like a welder or water heater.) Stoves and dryers need 2 hots and a neutral and a ground because they have 120v timers and buzzers and lights and stuff in addition to the 240v heating elements. You might want to run a neutral for use later while you are burying wire.

bob

[SQLit]

240 is correct, though 230-220 is interchanged freely. Just depends on who is speaking.

Romex is improper to put underground. The correct name is UF cable. Personally for the distance I would run conduit. That way if something happens later you have a race way to pull more wires. The size of the wire should include the distance the pump is down into the well. You can use this calculator to check the size of the conductors.

Motors draw a lot of current 6 times the running load when they start. Using to small of a wire only puts stress on the motor which can cause it to fail early. The pump should have a sealed cord not romex or bare wires doing down into the well. The cord is what protects the wire from the water which will eventually get through most single wiring insulation, even romex. UF would resist for sometime.

[Toller]

That is an interesting claim. Do you have any documentation that water will eventually get through UF insulation?

[Gary Slusser]

US volatge is commonally referred to as; 110, 115 or 120, 220, 230 or 240. All pump motors I'm familiar with will be called 230. Well cable (is not Romex) does not come with a neutral. And I strongly suggest the use of approved well cable rather than some other form of wiring. If you want another circuit 'out there' run one separately instead of trying to get 120 off one of the legs to the pump motor.

If you have a 2 wire pump motor (no control box above ground) you need two hots and a ground; called 12/2 w/grnd. If you had a 3 wire pump motor (control box above ground) you need two hot, a start and ground, 12/3 w/grnd. The motors don't require the ground but all present day codes do. I say 12 because that was mentioned. The size depends on distance and motor hp.

The cable should be direct bury but can be installed in a conduit if desired.

Gary Quality Water Associates

Bulletin Board

[Mark]

Make a sub panel and then have a dedicated well outlet, and light/outlet circuit

[Su Nombre]

Maybe run a cat6 cable too?