Well Wire Size

Arkansasoffgrid · March 2014

I have a 230vac 1hp well pump that is 300' deep, with a temporary male plug wired in at the top of well for a generator. Now I need to run an additional 150' from the well to the house and the ??? is what size & type wire does this need to be? Preferably direct burial.

waynefromnscanada · March 2014

Re: Well Wire Size

Since there is often confusion over sub pump HP ratings, with the traditional HP rating referring to the shaft HP, and many folks now taking the HP rating as the electrical HP INPUT rating, can you tell us it's current (amps) rating.
Typically, a 1hp shaft rating will draw roughly 10 or 12 amps @ 230 volts. 1 hp INPUT rating will usually draw roughly half that.
The wire size needed, will depend on the amps draw of the motor.

Cariboocoot · March 2014

Re: Well Wire Size

To expand on what Wayne said, the continuous (running) Amp draw of the motor and the distance involved. As:

Minimum wire size to handle 12 Amps is 14 AWG.
14 AWG over 150 feet carrying 12 Amps @ 240 VAC has 3.89% V-drop.

So theoretically the pump (if those specs are right) would work with that wire size. However most of us would err on the side of caution and go up to at least 12 AWG for such an application.

mike95490 · March 2014

Re: Well Wire Size

is the pump running from Grid, Generator, or pure sine inverter ?? I'd guess a 1hp pump, will want a pretty stout inverter to feed it for starting. Do you know the wire gauge down in the well ? Does the well company have any records ?
Otherwise, I'd use at least 8 or 10 ga copper for the underground run, under-voltaged pumps suck more amps.

My inverter panel indicates my 1/2 hp pump consumes 1Kw running.

animatt · March 2014

Re: Well Wire Size

A few comments.

I have a truper submersible pump 1hp 110v. Not sure the exact model, but if i remember correctly pump can only deliver 40meters of head or about 57 psi at pump. I was wanting to pick up the 1/2 hp model but stocked locally it was not. Was fearing the surge.

Anyway my cotek 1500w 24v psw inverter powers it no problem. Trimetric says it uses about 650-700 watts when running. So in my case. It seems. the 1hp rating is based on electrical consumption. I have about 110 meters (~360ft) of electrical running to the shallow well.. 10gauge wire for the run. I would think 12 gauge would be fine for this poster.
From reading on here the length of the long cable may actually help.

Next comment is just an idea please correct me if i am wrong.
My well pump just fills a tank under no pressure. I do not have a check valve on the water line coming from the pump. My thinking if water bleeds back down pump is starting under less pressure and that probably helps with starting surge. Obviously my situation allows me to run without a check while most people would need a check valve.
Is my thinking correct. Without check starting surge should be less.

Texas Wellman · March 2014

Re: Well Wire Size

Attachment not found.Attachment not found.

No need to overthink this one. Here is your answer from Franklin's AIM. Since the max distance for a 1-HP motor is only 400' I would at least use #10 wire on the top. Lately I have been using 4-conductor cable (3 conductors plus a ground) just in case I want to convert it over to a drive or remote mount the C-Box later on.

Good luck.

Here is the link if you want to look the data over:
http://www.franklin-electric.com/aim-manual/page-11.aspx

There is also a formula for mixing wire sizes if you want to do that.

Arkansasoffgrid wrote: »

I have a 230vac 1hp well pump that is 300' deep, with a temporary male plug wired in at the top of well for a generator. Now I need to run an additional 150' from the well to the house and the ??? is what size & type wire does this need to be? Preferably direct burial.

Mangas · March 2014

Re: Well Wire Size

Thank you Wellman!

stmar · March 2014

Re: Well Wire Size

Arkansasoffgrid wrote: »

I have a 230vac 1hp well pump that is 300' deep, with a temporary male plug wired in at the top of well for a generator. Now I need to run an additional 150' from the well to the house and the ??? is what size & type wire does this need to be? Preferably direct burial.

10-3 UF w/grd should do the job. You should be able to find at a Home Depot and will not have to hassle with multiple runs. My 1.5 hp is on a 20 amp breaker and when I go to my alternative power it goes through a step up T-220 with 15 amp breakers, so your 1 hp should be good with 10 gage wire. Check the down hole cable and see what they used, it is probably 10 or 12, the UF should be less expensive that down hole well cable and will serve the purpose.

Well Wire Size

Comments

Categories