This is about a 200' run to a workshop/office. It was nicked during excavation several years ago and subsequently developed a break (water penetrated the patch and turned the aluminum to powder). At that time, I dug up the cable, and had a local electrician splice with some epoxy type connector, heat-shrink tubing, heavy taped and reburied.

The same cable developed a break again in the same hot leg (assuming water again penetrated the splice). I have 122V coming in to one side of the main panel breaker and around 40V to the other side (the compromised cable). I don't want to have to deal with another splice that will most likely break again, and am trying to make this fix as inexpensively as possible, so...

My question is, rather than dig up the cable and try to locate the break, is it feasible to run a single #2 underground aluminum cable (in a different ditch) and connect to the main breaker in place of the bad hot leg?

Your feedback is appreciated,

Jack

I believe the wire that failed most likely damaged other conductors in the conduit. Replacing all would be expensive.
Hopefully the problem is close to one of the ends, Not in the Middle.
Problem is likely where it was nicked before.

You could yse a TDR to find the break, but the problem may be finding the constants.

http://www.flukenetworks.com/FNet/en...cument=9820563

If you are correct and the splice failed, then you should cut the power to the run at the source. Then dig the cable up and examine the splice to verify that it failed.

If it has failed, then the correct fix is to either replace the entire run, if the damage is severe enough. Or, go to an electrical supply shop and purchase the splice connector for the size connector.

While you are looking at the cables, make sure that the damage did not compromise the other wire runs.

If you do not feel comfortable doing this work, then please hire a licensed electrician to do the work.

Just a note regarding the TDR. Its not worth it to purchase this device. You already know the proximate cause and location of the failure and you have isolated the failure to a specific cable by the voltage output levels.

Year ago, I ran into a problem where the Customer said they heard a big Pow, power went off momentarily, then back on and then they had 120 volt things working, but no AC or 240 volt stuff. I read 120 volts between each hotleg and neutral, and Zero volts between both hotlegs at the panel. Pulled the meter and got 120 volts to Neutral from both Hotlegs, AND 240 Volts between the 2 hotlegs.
I told Customer, somehow the wire broke on one leg and welded to the other hotleg, and the other leg broke open. The wires did not short to ground, but melted to the Conduit.
A couple of good tugs with a utility truck was only way to remove conductors.
It's a Rare occurrence, but if one conductor burned through, most likely did damage to other conductors. Good Luck.

Thanks all... fortunately I have been able to move all my needed circuits to the "still hot" slots in the service panel and am back up and running. Once I have a spare $300+ I will replace the entire run, but for now, my office has power and I can get some work done to pay for new cabling. ;o)>

To answer your original question, if you plan to dig a new trench, do not just run one new wire. That would not be allowed.

Install a new 4 wire cable in the new trench.