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wiring a 240V well pump

Posted by the_woodge (My Page) on
Sat, Mar 22, 08 at 22:49

I have a well pump inside my basement and need to bring it into the 21fst century. I have 240V wire going to a fuse box sub panel that supplies power to the well pump as well as to the heat furnace through a 115V transformer box. Is that really legal, or whoever did this was hungover after a drunk fest? Also, my well pump blows fuses quite often or has to be tripped to start the pump again.


Follow-Up Postings:

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RE: wiring a 240V well pump

I would make sure that both are on seperate circuits both with grounds. The tripping might be due to more current being drawn then the fuses will handle. So check the pump and wire size to make sure it is ok. I have mine on a 12-2w/g romex and it is on its own 2 pole 20 amp breaker. The heat is on its own 14-2w/g romex and is on a 15 amp breaker. You will need to know what each uses for power then see if the wire size and overcurrent protection or fuse is sized right for that device...hope this helps JD out.


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RE: wiring a 240V well pump

Unless you have a really strange electricial service....homes really do NOT have 220/240 service. They have 2 110 VAC lines, 1 neutral and one earth ground coming in from the pole or ground transformer. The previous post touched on this. "I have mine on 12-2/g Romex and it is on its own 2 pole 20 Amp breaker." The 2 pole breaker has one toggle/trip switch but it has 2 inputs from each phase of the house service and 2 outputs. If you look at or take your breaker box apart you will see how this is all layed out in the box. A picture is worth a thousand words. On a 220/240 appliance you carry 2 hot 110 VAC and a ground. The AC pump will take these 2 inputs and run 2 different windings on the motor. You are getting twice the HP as a single phase 110 VAC pump motor. It has been a while since I had to deal with this type of service. It has to do with the AC cycles I think. Like the previous post also mentions, you want to make sure the pump is getting its 2 sources of AC power from each of the home service lines.
I was not watching the well guy closely when we were replascing my well pump. He hooked up a 220 pump and we dropped it down 240 ft.down the hole and guess what. It did not run because the motor was only getting power to one phase/winding. We pulled it all up and put a 110 pump on and we were good to go.


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RE: wiring a 240V well pump

Actually bsmoodha homes ARE 240v. More accurately 120/240v.
You do NOT have one neutral and one earth ground coming in from the pole. You have two hots and a grounded conductor, or neutral.

Also, a single phase 240v motor does NOT use the two lines to run two windings. There are two windings but they are wired in parallel. Depending on the motor one is the start and one is the run winding. I won't go into depth on this though.

I have no idea what you mean by "You are getting twice the HP as a single phase 110 VAC pump motor."
HP is HP and wattage is wattage. Single phese is single phase. For the purposes of a residnce, EVERTHING is single phase.
The same motor wired for 120 will use twice the amperage as the same motor made and wired for 240v.

I don't know why you pulled up your well pump. You could have much more easily changed the wiring over to 240v. A 120v motor 240 feet down, and then run to the breaker, is a LOOOONG run. I'd hate to see the voltage drop on that circuit.

Woodge, sorry. I don't have any suggestions, other than to call an electrician in and check that mess out. Sounds pretty hairy.


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RE: wiring a 240V well pump

I have lived all over the country PA, Cal, Tn. Wi. etc. and the world and have only seen 220/240 VAC service only in Europe were it is normal. Yes, I know all homes are single phase. You are just suppling 2 hot at 110 VAC to ie: elect. dryer, A/C, well etc.
With a "220" motor you have 2 hot wire both carrying say 15 Amps at 110 VAC= 2X15X110= 3300 Watts total energy. Then a 110 VAC motor has 1 hot carrying the 15 Amps again at 110 VAC=1650 WAtts.1 HP equals 746 Watts or 550 foot-pound/ seconds.

I pulled up my well because the 3/4 galvanized pipe was cracked where it attached to the pump due to normal torque ing of the 110 motor/pump. I redid it with PVC and double check valves and an anti rotation "football."


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RE: wiring a 240V well pump

"You are just suppling 2 hot at 110 VAC to ie: elect. dryer, A/C, well etc. "

Ummmm, NO, to things like you well or A/C or electric heat you are supplying 240v! The 120v reference is to ground which is not a critical number with regard to a 240v circuit. It IS a straight 240v circuit.
A straight 240v circuit has NO neutral. You can ONLY get a 120v circuit with a neutral.

And homes in the US are 120/240v!! Not 120V x2, and NOT straight 240v.


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RE: wiring a 240V well pump

I hope you have more tact with your clients or are a Union electrician. petey


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RE: wiring a 240V well pump

No I don't. I'm always a rude SOB.
Thanks for asking though.

Tact. LOL! That's funny.
I'm not sure how you took that as not tactful. Still funny though.


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RE: wiring a 240V well pump

I think it is great you guys are fighting over my problem! You might find this hard to believe, but both of you guys really did help me out with my problem even though I had to sift through the arguing. Thanks.


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RE: wiring a 240V well pump

Hang an electrician long enough and you'll find a debate of some sort sooner or later.
It's in the SOP.
This is especially true when you get one extra hardheaded like me that hates to see misinformation.


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RE: wiring a 240V well pump

Whats the worst with mis-info is when teachers instruct it. I've been taking extra classes to practice more with industrial and motors and hear things all the time. The teacher making 30 students believe multi-wire circuits are a bizarre shoddy thing from the past. Teaching that white wires in romex can never be re-identified as a hot conductor. Industrial lab was fun tonight being instructed to splice 4 #10 conductors from 3 rigid pipes all in a 7.0cu in. conduit T fitting :) (total of 12 #10's in the condulet). The teacher is one of the supervisors/ long time electrician of a company that wires $2-$20 mill projects. Hah way off subject but had to share since I too was very frustrated with mis-info tonight.


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RE: wiring a 240V well pump

DOH!
That first line in my last post should read: "Hang around an electrician ling enough..."

Don't any of you get any ideas. :P


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RE: wiring a 240V well pump

"Unless you have a really strange electricial service....homes really do NOT have 220/240 service. They have 2 110 VAC lines, 1 neutral and one earth ground coming in from the pole or ground transformer."

bsmoodha implies that there are 4 wires coming in from the POCO. There are only 3, as the neutral and grounded conductor are the same. That's why the neutral and ground buses are bonded in the main panel.


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