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230V Two Wire Submersible Pump

Posted by rltunnell (My Page) on
Sat, Oct 8, 11 at 8:42

I would like to drop a deep well pump into my lake to supply water for the yard and garden. I have a Deep Well 4" dia. Goulds pump 3/4 horse 230V Two wire 1 Phase. It will be about 200' from the Breaker Box. I am guessing 10/2 wire, 30 amp Breaker? How do you Wire up a Two wire pump to for 230V? Thanks


Follow-Up Postings:

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RE: 230V Two Wire Submersible Pump

Just a pressure switch in the line. But protecting those conductors from damage will be a challenge in the scenario you describe. And protecting the pump from in-taking debris-laden water will be another challenge.


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RE: 230V Two Wire Submersible Pump

It's a 4" diameter about 4' long with built in strainer for Deep wells. I don't think Debris will be a problem since the lake is deep, I can suspend it in about 10' of water. I was mainly concerned about only two wires. Does it need a Neutral/Ground or just the two wires from the 30 amp Breaker? I can do the pressure switch, just connect to one of the two wires? Thanks


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RE: 230V Two Wire Submersible Pump

Two hots and a ground.

No neutral if the motor is a 240 V load.

Cable does not count ground, so it will be labeled 14/2 with ground.

Cordage DOES count the ground conductor.
14/3 with white, black, and ground.


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RE: 230V Two Wire Submersible Pump

"Does it need a Neutral/Ground or just the two wires from the 30 amp Breaker? I can do the pressure switch, just connect to one of the two wires?"

Your two wire pump has two hots and both must be broken by the pressure switch or whatever control you use, i.e. timer, relay etc.

Some areas now enforce three wire pumps & grounding requirements in well service. I am not familiar with code in your usage. Used to be water and steel well casing were considered ground.

Your service supply obviously should conform to code whether buried or overhead. Don't guess at conductor size and voltage drop. Determine the pump load at that distance and select ampacity within that range. Size the breaker to the load. IOW, hypothetically you could have #6 wire protected by a 15A breaker.

Consider running three wire w/g in the event you want 120V at the line/load connection.


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RE: 230V Two Wire Submersible Pump

"both must be broken by the pressure switch or whatever control you use, i.e. timer, relay etc. "

No, breaking one will shut the pump off.

A service disconnect must open both hots, but there is no real reason to open both in pump control circuits.


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RE: 230V Two Wire Submersible Pump

Based on my experience plus the fact that most of those pumps have a Service Factor of 1.5, the #10 wire will be fine for your installation.


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RE: 230V Two Wire Submersible Pump

"No, breaking one will shut the pump off."

That's true. The OP asks about the pressure switch, which breaks both legs.
If the service disconnect isn't at the pump hook up it's a lot safer to kill both hots before servicing the pump.


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RE: 230V Two Wire Submersible Pump

"The OP asks about the pressure switch, which breaks both legs."

Save some money and use a single pole switch with a higher quality contact.

Any number of thew A/C condenser manufacturers have gone this route.

No more crappy contactor with copper contacts, but an actual single high quality relay contact.

There is no reason to open both lines in a straight 240 V circuit.


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RE: 230V Two Wire Submersible Pump

A pressure switch is not a reasonable disconnect no matter how many legs it switches. He'll need both.


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RE: 230V Two Wire Submersible Pump

"A pressure switch is not a reasonable disconnect no matter how many legs it switches. "

Yep, and no reason to have the expense of two contacts.


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RE: 230V Two Wire Submersible Pump

Again, correct. The purpose of the pressure switch is pump control, not line isolation.
Since differential pressure controllers for sub. pumps are double pole, the OP should hook his two line wires to the marked terminals and the load (2 wire pump) on the other side.
Personally, I've never had a problem with contact quality, and SP vs. DP are the same price.

Ronnatalie, I can show you lots of pump installations with no service disconnect, only line breaker a couple hundred feet away in the basement or in the barn. Sometimes frugality isn't the best choice.


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