Submersible well pump wire question?

Greg-VA · May 8, 2007

I posted this yesterday in the Electrical Forum and thought I should also post this here as well due to the experience of this forum on the subject.

If submersible well pump wire is classified as THW, then can any THW(or mtw, thhn, etc.) PVC jacketed copper (stranded or solid) conductor be used for a submersible well pump? At 10 AWG there seems to a choice between solid or stranded - which would be preferred? At current costs, three reels of 10 AWG THWN would be cheaper than one reel of 10-2 w/G twisted submersible cable. What was used decades ago before "submersible" classified wire was available?
Thanks!
(PS: I am going ~400FT to pump form well cap, so costs mount!)

Valveman · May 8, 2007

I like to use the stranded THHN, THWN in the 10-3 with ground or the 10-4. This is really underground burial cable but, it works fine in the well also. It is round like a rope and double jacketed. Very easy to install and last a long time. Some states have requirements for NSF standards. If you do not have these kinds of regulations, there should be no problem with using that wire.

Sponsor · 2022-01-29T12:20:58-0800

Speedbump · May 8, 2007

We use PVC twisted solid copper wire. It comes in 500 foot spools or 1000 if your Tarzan and don't mind lugging it around.

What are you getting quoted for sub pump cable?

bob...

Greg-VA · May 8, 2007

From pump to cap is ~400FT plus another 90FT to service panel. Quotes are running at $750+ for 500FT spool of 10-2w/g sub cable. I can get UF cheaper or just 3 spools of stranded thhn/thwn and cable tie/tape them to the drop pipe. I can get a 500FT spool for ~$80 shipped to the door! Much better price(3x80=$240)! Thanks for the responses.

Valveman · May 8, 2007

Three single conductors will be hard to keep from messing up down the hole, and you would need to pull through conduit for the 90' to service. See if you can’t find a 10-2 w/ground or a 10-3 in the thhn/thwn. Going to be higher than singles, but should be less than regular pump cable. I rarely even pull it through conduit underground, and that saves me a little.

Rshackleford · May 8, 2007

do not use the braided kind. it is prone to failure. our company does a lot well services and we do a lot of braided wire replacements. the wire has a rubber coating that is a pain in the but to strip and it tends to rub off over time and cause faults.

get a jacketed thhn designed and ul listed for submersible use. we use paige wire but there are many others out there. jacketed flat thhn is by far the best. it also fits tights against your drop pipe and stays out of the way of other things. don't worry about money, servicing a well is expensive and it is better to do it correct the first time. we don't do anything cheap at my company and we don't use twisted wire.

also, you cannot use the same wire for burial as for down the well. you will need use or uf for that. you must follow the ul listings.

Valveman · May 9, 2007

I also do not like the braided or twisted wire, especially with the neoprene (rubber like) coating. Paige is a really good wire, and if you have a tight fit, the flat jacketed is great. I prefer the round jacketed if there is room, as you don't have to worry about keeping it flat against the pipe. I know the round jacketed, underground burial cable is not rated for submersible use but, I have only installed a few million feet of it in all sizes and in all kinds of water wells with no problems. I have been running it underground and then right down the well for decades. However, if UL listing is important to you, you will need to use cable rated for submersibles. I have also found that even what I would call cheap wire, will not rub off over time if you eliminate as much cycling of the pump as possible.

Gary Slusser · May 9, 2007

Flat is best IMO and there is only one time to do it right, that's the first time 'it' is done. You'll wish you had in maybe only a few years if you skimp on this due to wanting to spend the least money now. Actually the least expense is to do it right the first time regardless of the price.

IMO the type of cable depends on the type of well, fully screened or rock bore? I strongly suggest only flat in rock bore wells. I also do the same for one continuous piece from the pump pig tails to the top of the casing. You don't want more than one splice kit; especially in a rock bore well where you want a cable guard every 15-20 feet with 5-6 wraps of water proof tape between them and no torque arrestor.

And no "safety rope" of any kind.

Don't forget the CSV and small pressure tank.

And leave ample room for the water treatment equipment.

Speedbump · May 9, 2007

My personal favorite is PVC jacketed twisted solid copper.

I don't know where you were shopping, but I sell a 500 foot spool of 12/2 with ground for $300.80, 12-3 with ground for $423.19 and 10-3 with ground for $611.27. They must be quoting full list price plus 20%.

What horsepower motor are you installing? That is what will determine the size of wire needed.

bob...

Raucina · May 9, 2007

I use flat UF cable. Rocks and gophers would destroy buried cable around here- conduit is cheap insurance above ground.

Rshackleford · May 12, 2007

you must follow the ul listing. it is there for a reason. it is for safety. your safety, the next person to work on the well, and future well owners.

very good point about the safety rope. never, ever use safety rope. if it ever falls down the well you can plan on drilling a new well.

Raucina · May 12, 2007

Just pulled 800 feet of pipe and poly rope from a well. The rope is like new contrary to many opinions including my own. Out here all the wells are at least 6" so a dropped rope usually does not plug up the well as it might on a
4". The age is about 32 years on the rope!

Speedbump · May 13, 2007

I just never saw the need for a rope that had a burst strength of less than the pipe the pump is hanging on, fittings included.

bob...

Raucina · May 13, 2007

A few times I have pulled pumps from the rope where otherwise one would have to try the wires. These were about 150' deep and on poly pipe that broke at the hose connector. Thus, one only pulls the weight of the pump and not the pipe in such a condition.

Gary Slusser · May 16, 2007

Raucina said:
A few times I have pulled pumps from the rope where otherwise one would have to try the wires. These were about 150' deep and on poly pipe that broke at the hose connector. Thus, one only pulls the weight of the pump and not the pipe in such a condition.

Then it seems to me that the cable and drop pipe weren't taped or otherwise held together or as you pull the rope to lift the pump, the motor pigtails have to pull apart from the cable or if not, the cable/pipe is pulled until it prevents lifting of the pump because the drop pipe can't make a 180 in the diameter of the well....

I'd like to see the guy or pump that can break PE pipe.

Raucina · May 17, 2007

I mean a break in the poly pipe at the pump, or corrosion break of a chinese steel hose barb at the pump. [Melamine in our dog food - junk steel in pipe fittings]

Thus, one would pull the pipe and wire as another would pull the rope with pump attached concurrently. Any variation in pull simply breaks the tape. It all still comes up. If the break was at surface and allowed the PE pipe to go down the hole, then obviously you need to fish that before pulling on the rope.
"the motor pigtails have to pull apart from the cable"

I never saw the motor wires or splices connected to the cable or rope. But if it was done, I cant see that it matters under these circumstances

Speedbump · May 17, 2007

Ropes, Cables and Torque Arrestors are what you find when a pump is installed by a home owner. Most pro's don't use those items.

bob...

Submersible well pump wire question?

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