We have a pump that turns on with a float switch that is broken and was removed from the contactor switch - so I can't see how it was wired in.

The good news is, we have a circuit breaker dedicated to this circuit and the pump works just fine when I press in the contactor with a 3 foot long piece of plastic trim.

So everything works, but I can't stand next to the pump for two hours daily to send water up while we wait for a new float switch.

The contactor switch looks just like this one:

enter image description here

... and again, everything works great ...

So, what wire(s), connected between which connectors, would impersonate the float switch and just be on so that I can turn on the pump with the circuit breaker and then turn it off with the breaker ?

Currently no wires are attached except for the four high voltage wires going into all four actual terminals. I have no wires attached to the side tabs.

I thought it was as simple as jumping from one side tab to the other, but I think that is wrong - I think I need to connect one side tab to one bottom terminal and one side tab to the other bottom terminal ?

Possibly using little jumpers with a knife connector on one end and a ring connector on the other ?

Thank you.

  • 1
    A float switch is usually use to make the on/off operation automatic safely, so you do not need to stand around all the time. A float switch can turn on/off something when water gets too high(sumps, toilets) and flooding, or turn off if water gets too low(water pump) to prevent burning up the pump.
    – crip659
    Commented Dec 14, 2022 at 2:04
  • Correct wiring of float switch into two pole contactor for well pump "The key for me in understanding this was that the contactor coil could be operated off 220v and didn't need a neutral."
    – Mazura
    Commented Dec 14, 2022 at 2:27
  • 1
    You'd have to bridge both contacts; not that I'm recommending that. As long as you "have no wires attached to the side tabs" go nuts I guess. If you called me in to do this I wouldn't. I'd say you're SoL until I come back with the right part. The 'white' is not a neutral. Cease and desist.
    – Mazura
    Commented Dec 14, 2022 at 7:01
  • 1
    @user227963 Neutral would be white. That third thing is ground, ground is green or bare and is not neutral and must not be used as neutral. They are using /2 cable (black-white) for 240V, and they should have marked the white wires with colored tape (preferably red) to make clear they are hot wires and neutral is not present. If you're all "huh?" then see this youtube.com/watch?v=fJeRabV5hNU or this youtube.com/watch?v=jMmUoZh3Hq4 Commented Dec 14, 2022 at 7:51
  • 1
    And I would change that sucker to a 24-volt coil contactor. That way you can use a 24-volt low voltage transformer and plain old thermostat wiring to wire up the float. That's safe and easy to work with. Commented Dec 14, 2022 at 7:55

1 Answer 1


Normally on a sump pump you just have a hot and a neutral. If you hook these up to power at an outlet, the pump turns on. An old school float for a pump is just a switch on one leg of the pump, so you'd normally find the hot leg going to the float and returning from the float and connecting up to the pump hot leg.

I don't know what your contactor switch does.

I usually go for the electronic float switches and then you just plug your pump into the HC6000 and set the high / low probes for precise on/off control.

  • Seems like a waste of (something) electronics when a plastic ball can do the same thing, and been working well for decades.
    – crip659
    Commented Dec 14, 2022 at 2:21
  • nah, the plastic mechanical floats can get hung up and can seize. The electronics are just two metal probes and you can easily set the hi and low levels all the way down to the lowest your pump will still pull water. mechanical plastic float can't be adjusted precisely. Commented Dec 14, 2022 at 2:31
  • You're saying you don't know why the contactor switch is there and I don't know either ... but I see the pump clearly labeled as wired for 230v .. and the old float switch looks very light duty - 14ga wire at best - so maybe the thinking is that float switches aren't always rated for 230v so you need to set up with a relay like this ? I really don't know. I just need to turn this pump on for 60-90 minutes at a time without standing there with a plastic stick for 60-90 minutes and wiring in a new float is logistically very difficult, currently ...
    – user227963
    Commented Dec 14, 2022 at 6:50
  • @FreshCodemonger Not if they're decently designed. The trick is don't create odd mechanism movements that don't need to exist. Commented Dec 14, 2022 at 7:54

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