Power to new barn problem - need testing advice

lhfarm · Oct 3, 2005

When I was using my BH to find the water line to the old barn so I could have water in my new barn, I snagged and broke both the water line and power cable (10/2 w/o ground). I got the water line run in and thought I'd drop a power line in the trench to the new barn while I was at it. I am going to run a new service line to the barn, but thought it would be handy to have another power source for now.

I wired up an outlet, and using my volt/ohm meter, have a reading 122v. Plugged in a small drill and nothing. I didn't have a test lamp, but with the VM plugged into one socket and the drill in the second, pulling the drill trigger causes the volts to drop to nothing. /forums/images/graemlins/confused.gif

Is it possible that I damaged the cable in more than one place when I snagged it? Are there some tests I can run to check the wire? Any advice appreciated. Thanks,

EddieWalker · Oct 3, 2005

If you have 122 volts at the wire before you connected the outlet, then I'd say the wire is working for now. No telling how thing you stretched it when you broke it and what problems you will have in the future, but for now, if you have 122 volts, the wire isn't your problem.

Check the plug and how well the wires are connected.

Eddie

BB_TX · Oct 3, 2005

Actually it is possible for the wire to be the problem. If there is a very poor or high impedence connection it can read full voltage as long as there is no load. But as soon as you put a load on it, all the voltage drop will be across that poor connection leaving nothing at the intended load. Possibly the wire could have broken and is barely making contact. Sort of like on a car (or tractor) when you have a bad battery cable connection. It can read 12v until you hit the starter, then it drops to zero. As Eddie said, check all your connections from source to outlet to eliminate those. Then start on the wire.

lhfarm · Oct 3, 2005

I've been pretty careful with the connections, although I am using "wet condition" wire nuts instead of a proper splice. There is an outlet in the garden and it works. So I know the problem is beyond that point (about 100' from the old barn). I'll disconnect everything at the "break" and try a full load test there. Thanks for the advice.

wushaw · Oct 3, 2005

I'd say there is another break in the wire.

BB_TX · Oct 4, 2005

You can try checking the resistance of that stretch of wire. You can disconnect both wires at both ends. Then at one end, tightly connect those two wires together. At the other end, use your ohm meter to check the resistance of that wire loop. 10 ga wire, if I remember correctly, should be about .2 ohms per 100 feet. So you should read about .4 ohms for a 100 ft loop. You will need a digital VOM to read that low resistance.

blackmajicwoman · Oct 5, 2005

Another possibility is that you broke the neutral (ground) when you stretched the cable and you are reading 122V because you might be literally grounded (earthed) on a separate path to ground, which would cause a high impedance, but not enough current to power the drill. Just a thought. Try measuring the resistance between the neutral on the receptical and ground. If it is 0 ohms (or close), pay no attention to my suggestion. If it measures really high (or open), that could be your problem.

Soundguy · Oct 5, 2005

I'd also re-check the connection at the plug, maybee even check hot to neutral, hot to ground, and neutral to ground and see what pops up. also check each to earth ground... easy to do with a vom.. just plant one probe in the ground...

My bet is bad connection somewhere.. either at a 'bad' plug.. or at a bad splice/ break/near break in the wire... Could be a capacitive coupling witha break int he wire and some moisture making the connectionfor the no-load voltage as another poster(s) pointed out.

Soundguy

rambler · Oct 5, 2005

My bet is the wire stretched & broke. The ends within the insulation touch & provide voltage, but they do not touch well enough to provide current.

Do you have a ground wire, you just said you ran 2-10 wire, not sure if you also have a ground....

--->Paul

mffarmall · Oct 5, 2005

The best advice is to replace the line. Don't put your wires in with your water line and always use a ground. Put the wire into conduit. The cost might be more but the amount of time saved will increase. If you have some problems now and fix them you will probably have more later. Put a ground rod outside the barn. This will not only protect you but also your kids and years from now when your grand kids are running around your place. This also allows you to add more outlets or light when you need it.