Wiring From House to Well Pump?


Old 06-13-05, 03:25 PM
Flat Panel
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Wiring From House to Well Pump?

I just moved into a house which is on well water. I have added some filtering epuipment which requires some 120V circuits and I want to add an interior light to the pump house I just built. Anyway, I was trenching new water lines for treated and untreated water as well as adding some conduit for the additional power when I dug up the romex that was burried (not rated for direct burial, but was 24" deep).

How does one 'correctly' get power from my sub pannel out to my well pump (2hp) 150 feet away?

The original owner ran some 12-2 romex from the CB, up the wall, into and accross the attic, down the wall, horrizontally under a window, and out to a junction box on the outside of the house. It was then spliced inside the junction box with wire nuts and into some 1/2" EMT conduit which only went into the ground about 18" and then the conduit stopped. The rest of the wire was just directly burried unitl it came back up to the pump house where it endered some more 1/2" conduit and another junction box. From there, it was wired directly to the static converter (pump control box).

Some of the J-boxes were really corroded inside and I just want to replace the entire system and start over.

I can run wire up into the attic or down into the crawl space.

I would like the wires to be in conduit for protection and ease of adding/replacing circuits if I ever need to. What are the best methods of doing this?

Does discrete wire have to be in conduit from the sub panel and through the walls?

Would it be better to use romex inside the house and convert to THWN outside the house in a J-box?

Should I use J-boxes at the exit of the house and the enterance of the Pump House just to have a disconnect of the wires for shorter lengths just incase something needs replacing?

How far away from water pipes should the conduit be? Should I backfill the pipes and conduit with sand for protection and an indicator while digging or trenching later?

I have lots of specific questions to come, but these will get me started now.


Old 06-13-05, 06:45 PM
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I recommend using at least 3/4" PVC conduit {& boxes} on a run this long. the entire circuit doesn't have to be in pipe, NM can be run in the attic to a point to make a transition to conduit.Depending upon the codes in your area you may need a disconnect switch for the pump.The trench must be atleast 18" deep,if you get the job inspected the inspector may say this depth is measured from the top of the pipe to the edge of the trench. J-Bs are not needed where it enters the house just use LB fittings,they make the wire just as accessible.
I think water lines must be a minimum of 6" away from conduit,but I'm not sure on that.After running the conduit backfill the trench about 14" then run "CAUTION ELECTRIC LINE BURIED BELOW" tape along the trench then backfill the rest
Old 06-14-05, 09:36 AM
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Can I run 10/3 w/Gnd NM (or similar wet rated) wire in PVC conduit for the entire burried run?

What is the best way to sleeve the wire as it exits the house where the stucco is? Does the LB fitting stick through the stucco enough to not need to worry about it?

Do I have to secure the wire to the studs on vertical runs inside the walls? If so, how can I do this without tearing the walls apart?

If I run out of the sub pannel down the wall and through the floor, where is the best place to transition it into conduit? Should I just install an LB fitting at the floor through hole and run conduit under the house?

What is the best way to exit the foundation? Should I just install another LB fitting and punch a hole in the vent screen for the conduit?



Last edited by Flat Panel; 06-14-05 at 10:05 AM.
Old 06-14-05, 09:42 AM
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You cannot use NM outdoors, even if in conduit. Conduit is wet, and needs waterproof cable.
Old 06-14-05, 10:06 AM
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Originally Posted by racraft
You cannot use NM outdoors, even if in conduit. Conduit is wet, and needs waterproof cable.
Oops. I realised that after I wrote that. What I ment was....is there a Wet rated cable that can be run in conduit?

Old 06-14-05, 10:29 AM
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Individual conductor THWN wire -- it will likely be sold as THHN but dual-rated THWN.

Type UF cable is rated for direct burial and wet conditions. It is up to your local inspector, however if it is allowed in conduit underground; it is an ongoing debate. The safest choice is individual conductor THWN.
Old 06-14-05, 01:49 PM
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Since you need power for the well pump, filtering equipment and light/outlet I would run a 8/3+ground or 6/3+ ground to the well house and put a small subpanel at that point. I'm not sure if you're allowed to have that many individual circuits run to that building. The wellhouse will need a ground rod installed also.

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