Voltage loss in underground cable.. FOUND IT!!!

[Bluebinky]

100+ ohms resistance on a wire is far less likely (IMHO) than inductive or capacitive coupling or feedback from the other "hot" wire (from say a timer/controller in a 240V load).

Since it was "properly" wired, that blows my theory of a both "hot" wires being on the same phase with the neutral "hot". (trying to be careful with the word "phase" here to avoid upsetting anyone)

 

[Lone Star Charles]

Sure is a puzzler. One quick check that you may have already tried but if not, might give you a little more information.

• disconnect all of the conductors (L1, L2, & N) from their connections on both ends
• connect all three conductors together at one end of the run
• from the other end, measure the resistance between each of the three combinations - i.e. L1-N, L2-N, and L1-L2.
• you might also add in resistance measurements to ground
• I'm not entirely sure what the result will be, but it may give you additional insight about impedance in any of the lines

This may tell you what to look for. Unfortunately, it will probably not tell you where.

Cheers
Charles

 

[Sponsor]

 

[Chuck Shaughnessy]

FOUND IT!!

Just outside the barn is a water hydrant and a lot of rocks. The wires are underground very close to the hydrant and I have had to dig near there in the past replacing hydrant parts. I have never noted a nick in the electrical wire, but I thought I would dig it up and see if it was all ok, if a rock had damaged it ... or just to see if I could see anything wrong.

And ... what do you know I found a highly corroded cable - it looked like the insulated had been stripped off of a couple of inches at the top, the aluminum exposed, and it now looks like white chalk - easy to spot in our Virginia clay. I yanked on it to get a closer look and it broke completely in two. That #2 AWG aluminum cable ... just broke in two.

So now .. I need a recommendation on an underground splice kit for #2 AWG aluminum wire. It is only about 8 feet from the box so I will just splice it there and install a new wire from the splice to the box.

I wonder how much current (and power bill dollars) i have been dumping into the ground!!!

Thanks for everyone's help...

Any recommendations on UNDERGROUND SPLICE KITS?

 

[MikeJ45]

I had the same problem replaced the wire from house to barn then one leg stopped did the same thing and only had 120v on one leg lasted another 2 months now its gone this whole new run only lasted me about 5 months I am so frustrated and don't understand why this has happen 3 times in a year any suggestions ? guess I have to put in another run again maybe put in conduit next time ? Only thing I can think of is a critter of some sort ? Please any help would be great. Do you have any more issues since repair of your situation ? Thanks

 

[WorthFlorida]

I had the same problem replaced the wire from house to barn then one leg stopped did the same thing and only had 120v on one leg lasted another 2 months now its gone this whole new run only lasted me about 5 months I am so frustrated and don't understand why this has happen 3 times in a year any suggestions ? guess I have to put in another run again maybe put in conduit next time ? Only thing I can think of is a critter of some sort ? Please any help would be great. Do you have any more issues since repair of your situation ? Thanks

What type of wire? how deep, how long? The above had aluminum wire and just a pin hole in the insulation will start the corrosion and it goes pretty fast after it starts.

https://www.familyhandyman.com/electrical/wiring/how-to-bury-underground-cable/

 

[Ballvalve]

So now .. I need a recommendation on an underground splice kit for #2 AWG aluminum wire. It is only about 8 feet from the box so I will just splice it there and install a new wire from the splice to the box.

I wonder how much current (and power bill dollars) i have been dumping into the ground!!!



I know this thread is ancient, but it seems he should have put a ammeter on the 120 volt end of that damaged cable to see if any current was indeed flowing to ground.

 

[Fitter30]

Awg is how the wire is measured whats the other letters?

 

[Jadnashua]

We don't normally think of aluminum as being a highly reactive material, but if you've ever seen a thermite reaction with iron oxide powder and powdered aluminum react, you might think otherwise! Once you get that reaction started, the aluminum literally sucks the oxygen out of the rust, leaving molten iron. The aluminum REALLY wants to become more stable, and its affinity for the oxygen is higher than that of the iron.

Aluminum remains stable because aluminum oxide forms a crust on top of the metallic aluminum almost instantly, and, unlike iron oxide, aluminum oxide is almost exactly the same volume as metallic aluminum, so it does not expose more of the metal to corrosion, and protects it (it's also harder than the metallic aluminum). So, anything that might abrade the aluminum could cause it to literally rust away entirely. Take away the protective insulation, some abrasive soil or rocks, seasonal expansion/contraction, and that's enough. Moisture can speed it up, some, too.