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Mike G.
Mike G., Master Electrician
Category: Electrical
Satisfied Customers: 6988
Experience:  Proven Professional 46 years Experience
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I am wiring a new 230v pool pump to an existing switch box

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I am wiring a new 230v pool pump to an existing switch box - due to corrosion and needing longer line from switch to pump I have to rewire the new switch and new line to the pump. I am confused about what I would normally think of as a ground wire. It is a 4 wire line from the panel box with the following readings: BLK to RED = 230v, BLK to WHI = 115v, BLK to COP = 115. RED to WHI = 115v, RED to COP = 115v, WHI to COP = 0v. Previously the line was wired like this: BLK and RED to the LINE IN side of DPST switch. WHI LINE in tied together with the COPPER wire from the LOAD line. The Copper from Line was grounded to box. So I ran the LOAD line (3 wire, BLK, WHI, COP) with the BLK and WHI on the LOAD side of switch to the terminals in the pump, BLK going to L1, WHI to L2 and the COP to the ground screw. I have not applied power to the pump yet as the the copper ground wire carrying voltage across the BLK concerns me...It seems like this would be electrifying the housing of the pump?? I don't want to fry my new pump or myself. Is this the correct way? The old pump had 3 wires coming to it the BLK was L1 and the WHI was L2 and there is the copper but I don't recall what it was connected to - I don't see a specific ground terminal in the old (really old) pump. Can you help with my question about tying the white line in to the copper load line? thanks, LH
Hi, I'm Mike and I'll be glad to assist you. The reading given indicate that the neutral is open. That means that its not connected somewhere in the circuit. It could be a bad connection in the panel or a wirenut in the circuit. As far as connecting the ground and the neutral together, that is prohibited. The only place they come together is in main service equipment. Connecting them together creates a shock hazard. The gound connection at the pump should be in the wiring compartment on a green screw. If ther screw is missing look for a threaded hole and replace the missing screw.
Customer: replied 4 years ago.
So if I omitted (cap it) the white wire from the line in and and did not tie it to the ground wire of the line out - then could I just connect the black and red (230v across the two) to the Line in side of the switch and black and white from the line out to pump L1 and L2 and the copper ground to the green ground screw in the pump housing? Would that safely deliver the 230v to the pump? Also, the pump is factory set for 230v, but you can change it to 115v - what is the advantage to running 230v? thanks
Let me add one more thing. The ground wire needs to be insulated. If the ground you have is bare copper, it can't be used on a pool pump. The white wire that isn't being used will have to be marked with green tape and used for the grounding conductor. There isn't a need for a neutral on a 240V motor. The selection of the voltage is optional. Using the higher voltage is always the best choice. It will be less subject to voltage drops and run at a lower amperage.
Customer: replied 4 years ago.
OK, I have four wire Romex to run the line to the pump, so I will use Black and Red for the load out and mark the white with green for ground and omit the bare copper. And will cap off the white line in as it seems unecessary. I think that is what you are telling me.
The white will be used all the way from the panel to the pump. In each box it will be marked with green taps to show its use. The bare ground will be cut off.
Customer: replied 4 years ago.

the white wire from the panel has voltage on it - from the first description, both the black and red wires from the panel each read 115v across the white. I was saying omit the white from the panel, cap it, use the ground wire from the panel (bare copper) and tie it to the insulated white wire and take that to the pump as ground.

The pump has no need for a neutral. There shouldn't be voltage on that wire. Check to see if it is connected to anything else. If there is a 120V load the problem will remain in not having an insulated ground wire.
Mike G. and other Electrical Specialists are ready to help you
Giving me a neutral feedback say you didn't get the answer you wanted wasn't necessary. We can continue until you are satisfied. The only wires needed for a 240V pool pump motor are 2 hots and a ground. All wires have to be insulated. The use of NM cable is permitted inside the house and if you have a 3 wire with a ground, the white is marked green and used for a ground. There should be no voltage on the ground. If you are using it to test the hots, there will be a voltage reading from the hots. If you were testing between the bare ground and the white there shouldn't be a reading. Further checking will be necessary to avoid a shock hazard. The answer is the way it has to be.

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