I have a broken neutral wire somewhere underground running from my house to my barn. It has an 70 amp circuit breaker in my house 200 amp service panel supplying a small panel in the bard. The run is about 200 ' using 2 gage aluminum three wire, no ground.

Since I have to bury new lines, I want to increase the amps to the barn to 100 amps. I have a new 100 amp service panel already installed in the barn. I want to use copper THHN-THWN wire to make the run to the barn instead of aluminum.

The existing bad aluminum wire passes underneath my driveway and two sidewalks for a total of 45 feet about midpoint in the run. The utility company has already been out and marked where the wires are between house and driveway and between driveway and the barn. I have already begun hand digging at the driveway to see if there was a conduit surrounding the old aluminum wires. Unfortunately, they were buried without conduit (no surprise about the broken neutral wire). However, I discovered that a 1-1/4" plastic water line (no longer used) was buried in the same trench when it was dug just above the old wires.

My question is this: Can I snake the new copper wires through this unused plastic pipe in order not to tear up the concrete, or having to rent a boring machine? Thanks for anyone's help. Rick

This is a dilemma. I may as well be the bad guy.

You know that you should not use the water line, and no one that is a qualified electrician can tell you that you can.

While it may be very similar to conduit, any raceway for wiring must be UL listed to be used as a raceway.

If you do use it, it probably is unlikely anything will happen, and probably last for years.

However, if something does happen, the line breaks, earth or pavement becomes energzed, (Don't laugh, it has happened) and someone gets shocked, or worst, then what?

You can ask the local inspector, even if he says yes, you assume all responsibility. I doubt he will allow it.

The choice, and risk is up to you.

Better that you install UL listed electrical conduit.

Thanks for your input. I thought the wire that I was going to use could be buried without conduit. If it isn't, what can I use that doesn't require any? I thought that even plastic water line is better than no conduit at all. Am I wrong?

Rick

OK, maybe a loophole here.

Since you stated THHN/THWN , I assumed all conduit system, since THHN/THWN is not rated for direct burial.

If you use USE, UF, URD,or anything else rated direct burial, and use the water line as a sleeve, I see no problem.

Keep in mind that you need a minimum of 18 inches between the top of the wires and the top of the driveway. If the old water line isn't deep enough you can't use it.

If it is deep enough I'd cut the water line on both sides of the driveway and use it only to get from one side of the driveway to the other.

Excellent point I missed,


Keep in mind that you need a minimum of 18 inches between the top of the wires and the top of the driveway. If the old water line isn't deep enough you can't use it.

If it is deep enough I'd cut the water line on both sides of the driveway and use it only to get from one side of the driveway to the other.

There are contractors that use machines to bore laterally without disturbing the ground except at each end. But these machines and the operators aren't cheap. May be an alternative to tearing up the driveway. They bore the hole, and pull the flexible conduit back when retrieving the auger. The flexible tubing is pvc, and fits standard pvc fittings.

Thanks everyone. You all have made good points. I think it is worth the gamble to use the water line and the direct burial wire. Someone gave me the wrong info to use the THHN-THWN wire, so I am grateful to get that cleared up before I bought any wire.

Sure glad you asked the question.

What scares me is the DIY'ers that don't ask questions, take someone's word or thinks they know what to do and how to do it.


I had two 5 inch lines installed 260 feet under a commercial parking lot.

Very slick operation, took about three days from set up to clean up.

Hope your sitting down...

Only cost $35,000.00