I am trying to install a new 2-speed pump for my pool. The controller is an Intermatic multipurpose control, which is different from my old junction box.

The power pvc pipe from the electrical box has two black wires and one white wire in it. The white wire goes to a terminal on one side of the old junction box and the two black wires go above and below the circuit breaker block.

The Intermatic box has two spaces for incoming power, but which two wires do I use? The two black wires or one black and one white?

Black and white seem to make more sense, one hot, one return to complete an ac circuit, but there are two black wires coming out of the circuit breaker block and each one goes to a terminal strip marked "line" on the old junction box and I don't see that the white wire does anything.

Help!

The sounds like a 240v circuit. There is no "return" wire in a 240v circuit. In fact, return is generally not a term used in AC wiring. You are thinking of the neutral.

If this is 240v then I am not sure why white was used, and what concerns me is where is the ground wire?

I am actually pretty confused by your description. To you it may seem clear, but you are looking at it. Is there any way you could post a pic of the equipment?

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Originally Posted by stanfortyman

The sounds like a 240v circuit. There is no "return" wire in a 240v circuit. In fact, return is generally not a term used in AC wiring. You are thinking of the neutral.

If this is 240v then I am not sure why white was used, and what concerns me is where is the ground wire?

I am actually pretty confused by your description. To you it may seem clear, but you are looking at it. Is there any way you could post a pic of the equipment?

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Don't have a picture, however, I did find out that the two black wires are the 240 volt wires from the main electrical panel. The whire wire is the 120 volt for the pool lighting.

Everything is grounded (literally) to a metal post/wire that is embedded in the ground beneath the pool pump concrete pad.

So now I know what the wires are, however, I can't figure out why the pump does not run. About the only thing left to do now would be to buy a meter and check the voltages at the motor.

Quote:

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Originally Posted by mvlaplante

Everything is grounded (literally) to a metal post/wire that is embedded in the ground beneath the pool pump concrete pad.

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This is NOT the equipment ground. This is a ground rod, and if this is what is being used it is wrong.
The earth has nothing to do with equipment grounding. A ground rod or pipe is a useless source of ground as far as this goes.
The earth serves a completely different purpose.
Many pool installers incorrectly install ground rods thinking they are required for pool bonding. They are not.

Quote:

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Originally Posted by mvlaplante

So now I know what the wires are, however, I can't figure out why the pump does not run. About the only thing left to do now would be to buy a meter and check the voltages at the motor.

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Well, trying to work on electric without a meter is like trying to paint without a brush.