Lost all power to the shed

Alien5044 · Apr 18, 2023

Sometime early spring, my shed lost all power. I found the 20amp breaker tripped inside the breaker box.
Tried new breaker, still just trips instantly. Literally nothing is normally "on" connected to this circuit, One or two light bulbs, a vacuum cleaner now and then, and a dock bubbler for the lake which was disconnected last fall.

OK so went down to shed and tested everything, and finally the 10-2 UF underground feed line that comes from the breaker box to the shed . Found no short between black and white wires, but did find a dead short between white and ground wire somewhere in the 225 feet of buried cable. I suspect the ground hog near the shed's foundation has found and chewed my wire underground.

At this point, I'm leaning toward abandoning the existing feel line and just running a new cable at about $175 for a 250ft roll, and renting a walk behind trencher to bury it. Not interested in the prospects of trying to dig this old cable up to visually inspect it. A short could be anywhere along its 225 foot underground length

Any other thoughts?

Dave55 · May 3, 2023

That would be fine, but it will not stop a ground hog. Slow him down, maybe, but stop, no.
If you did install conduit you could even run single strand wire and maybe save some cash there.
Also if you had problems in the future, you could probably pull the wire out and find out exactly where the problem is without digging up 225 feet of cable.

As far as that goes, if you are only running 3 #10 wires you could get away with half inch pipe.
3/4" would be overkill but easier to suck a string through.
A modified middle buster and you could plow that in if you bought a roll of black plastic pipe.

My craftsman 917.27308 · May 3, 2023

I don't think a ground hog is going to eat through schedule 40 duct. I have direct buried hundreds of millions of miles of it in four states over a 50 year period. Not once, was a duct eaten into by a rodent underground.

Alien5044 · May 3, 2023

No way am I digging up the old cable. At the most, if its not deep, I could winch it up with the UTV, that is if that wire doesn't break. UF is pretty tough stuff though. If it gets destroyed by the new trench, so be it. The local rental place will rent a small trencher for $80 for the day. I'd guess a couple hours would be plenty for the steep downhill trench. A 12" trench can be filled in by hand. This is down a slope covered in field grasses and scrub.
This, and all outdoor projects are still waiting on the rain....

MARK (LI) · May 3, 2023

I would use a few pieces of EMT ( less than 11 bucks for 10 feet at HD) or plumbing pipe right near the building where you think the attack on the wire took place...you can figure that out if you do pull the wire out with tractor or ATV and examine it for damage......then from that point onward I would use the less expensive ( although no by a lot) PVC conduit, and use the single strand wire suggested by @Dave55 ...A long time ago I helped a guy install an in ground sprinkler system and we used a sawzall with a 12" demo blade to cut the "trenches" in the ground and just pushed the plastic sprinkler pipe into the ground as we went along...it worked pretty well

Ariens93GT20 · May 3, 2023

Here the utility would like all new lines in gray electrical conduit. And they can refuse service if they find otherwise. They say it's more to protect workers than predator protection.

WNYTractorTinkerer · May 3, 2023

12-2 going 225 feet underground is a tad small for a 20A breaker. Up the wire size to at least 10-2 copper or 8-2 aluminum. (as it is over 100') With the bigger wire you could also go to a bigger breaker. (30A) As far as the meter showing no fault but blowing the GFCI breaker the small energy leakage to trip the breaker is millivolts which is way more sensitive than your meter. Th OHM test mentioned above is also of value for you to check. Grab a friend with a CUT and little backhoe to dig your trench for ya and save your back..

Dave55 · May 3, 2023

And in most locations the utility is concerned about the lines from their pole to the meter socket. After the meter socket, it's your baby. Likewise if you call Miss Utility, they will locate the line from the utility pole to the meter socket, plus or minus 6 feet. After the meter socket they won't even look for a line.

The 20 amp breaker on 12 awg copper wire is correct. However at 225 feet 6 amps is all you can draw without lowering the voltage to less that 115 volts.
If you run 10 awg copper wire put it on a 30 amp breaker, but you can only draw 9.5 amps before it drops below 115 volts at that distance.

Everything in the US is designed for 120/240 volts at the meter.
Everything you are powering is designed for 115/230 volts.
No matter how big the wire is, the longer it is, the more voltage drop you have.
So as an electrician you have to look at how many amps you need at what distance from the meter socket.
Then you select the correct wire size to get the correct voltage and correct amps to the device you are powering up.
In this instance if you wanted 20 amps at 225 feet, #6 wire will give you 20 amps at 115.9 volts. That #6 wire would be able to supply 24.2 amps before it drops the voltage to 115 volts. But if you look at the NEC, THHN #6 copper wire is good for 75 amps, so you can put a 75 amp breaker on that circuit, but if you try to use more than 24.2 amps, the voltage will drop below the 115 volts your device is expecting to have.
A side effect of trying to draw more amps is the wire starts generating heat. That also goes for the device you are trying to run, low volts and a motor will get hot rather fast. So now you are wasting power generating heat instead of doing the work you want the electricity to do.
THHN insulation is rated to 90C for a max temp. Exceed that, call the fire department because you will have a fire.

Another thing to consider copper versus aluminum.
#8 aluminum THHN is rated for 45 amps and at 225 feet 10.1 amps drops the voltage to 115 volts.
#10 copper THHN is rated for 40 amps and at 225 feet 9.6 amps drops the voltage to 115 volts.
So you went up a wire size and gained .5 amps to your device.
I never use aluminum wire to wire anything, I have run into to many problems it causes.

One more thing to consider, around here I live in town. If I go down to my meter socket and check the voltage, right now everyone is at work, no body home to use electricity, my voltage is probably 122/244 volts. Tonight it will probably be 120.5/241 volts. Out in the country where I originally was from 7 miles from the sub station, at the meter 125/250 volts or slightly more was not uncommon.

I used to pick on the linemen around here. I put in a 200 amp electric service and I am running 3/0 copper wire up the mast pipe. The power company shows up, they hook it up with #2 aluminum wire. Finally one day the crew supervisor finally came back with the correct answer. When the wire catches fire, it will not be in the house. But as usual, I was having to much fun that day. We all had a good laugh.

Ariens93GT20 · May 3, 2023

So you implying this may not have been a rodent but an overload combined with time.
How many heat cycles could his wire have to gone through before failure?
I see where you are coming from the wire needs to be larger or it to will fail in time.

Dave55 · May 3, 2023

Is the current wire aluminum?
The problem I have run into with aluminum is it expands with heat and it is a very soft metal.
The first time I ran into this problem, the couple had an electric hot tub and the heater was sizable.
The tub heater kicked on and then when it kicked off, half the electric in the house went off.
But it took a couple days to figure out what was going on and tie the problem to the hot tub heater.
When I finally figured it out it went like this.
The hot tub heater in addition to everything else in the house right much maxed out his 200 amp electric entrance.
So say the oven was on, the hot tub heater kicked on and the microwave and coffee pot were on.
The main wires in the breaker panel were getting warm, which caused the wire conductor to expand, which mashed the screws in the lugs into the wire even farther. After a year or so, when everything was off, the wire cooled and contracted enough the wire completely lost connection, half his breaker panel had no power. But with everything getting hotter and colder, eventually the power would come back on, but then so would the hot tub heater. Repeat process. When I finally found the problem, the bolts on the panel lugs were so loose I don't know how they had any electricity at all. Also when the wires were that loose, there was some arcing going on inside the lug and that was also damaging the conductor. Kill the power, take everything apart, clean everything, liberal dose of no ox and re torque everything, problem fixed. I have run into this problem 5 or 6 times over the years.
Last Christmas I was down at my sisters, power went out in part of the house. So I grabbed my meter and started checking. This time the problem was on the transformer, but when we called they got a lineman out in about half an hour. He pulled the meter cover off, no power to the meter on one leg. So he goes up in the bucket truck, touches the wires going to the transformer power out leads, one lead and sparks flew everywhere. Told my brother in law, he found the problem. So 30 minutes later the power was fixed.
So then my sister, we had 5 electricians out, none of them found anything wrong. How did you find that problem in under 45 minutes? Course her being my sister, well sis I am just that good. After waiting a little I finally told her, actually I have seen this before more than once, I knew where to look, which got me a slap on the shoulder. Sisters, they never change, but I guess brothers don't either.

MARK (LI) · May 3, 2023

Dave55 said:
Is the current wire aluminum?
The problem I have run into with aluminum is it expands with heat and it is a very soft metal.
The first time I ran into this problem, the couple had an electric hot tub and the heater was sizable.
The tub heater kicked on and then when it kicked off, half the electric in the house went off.
But it took a couple days to figure out what was going on and tie the problem to the hot tub heater.
When I finally figured it out it went like this.
The hot tub heater in addition to everything else in the house right much maxed out his 200 amp electric entrance.
So say the oven was on, the hot tub heater kicked on and the microwave and coffee pot were on.
The main wires in the breaker panel were getting warm, which caused the wire conductor to expand, which mashed the screws in the lugs into the wire even farther. After a year or so, when everything was off, the wire cooled and contracted enough the wire completely lost connection, half his breaker panel had no power. But with everything getting hotter and colder, eventually the power would come back on, but then so would the hot tub heater. Repeat process. When I finally found the problem, the bolts on the panel lugs were so loose I don't know how they had any electricity at all. Also when the wires were that loose, there was some arcing going on inside the lug and that was also damaging the conductor. Kill the power, take everything apart, clean everything, liberal dose of no ox and re torque everything, problem fixed. I have run into this problem 5 or 6 times over the years.
Last Christmas I was down at my sisters, power went out in part of the house. So I grabbed my meter and started checking. This time the problem was on the transformer, but when we called they got a lineman out in about half an hour. He pulled the meter cover off, no power to the meter on one leg. So he goes up in the bucket truck, touches the wires going to the transformer power out leads, one lead and sparks flew everywhere. Told my brother in law, he found the problem. So 30 minutes later the power was fixed.
So then my sister, we had 5 electricians out, none of them found anything wrong. How did you find that problem in under 45 minutes? Course her being my sister, well sis I am just that good. After waiting a little I finally told her, actually I have seen this before more than once, I knew where to look, which got me a slap on the shoulder. Sisters, they never change, but I guess brothers don't either.

On Long Island there were several fires in relatively new construction in the '70s because of aluminum wiring traced specifically to this action.

Alien5044 · May 3, 2023

Dave, if you were asking me the OP, no it is not aluminum, the existing UF cable is all copper as will be its replacement. When the rain stops and after I mow the property, next up is some light digging just to see if anything near shed is eaten away. I may try the UTV winch and see if I can pull the old out for recycling but if it is rough going, it will have to remain for some future archeologist to discover.

Dave55 · May 3, 2023

I will not use aluminum wire. It has to be twice the size, that makes it a pain to work with, oxidation is a real problem at every connection and it does what I described above. Not worth it to me or my liability insurance.
If a customer can't afford copper wire, they can't afford me either.

Is that circuit on a ground fault breaker?
I have seen water inside the outer jacket of regular romex cable trip a GFCI, but I have not run into it tripping a GFCI on UF cable, yet, but I see new stuff happening all the time.
With the way GFCI breakers work, the power out on the black wire has to exactly match the power coming back on the white wire. Any leakage on the white or black trips the breaker.
On a normal breaker you can short the white wire to the ground wire, no problem.
On a GFCI, big problem instantly.
I did not think it was aluminum, those problems above are aluminum wire specific, but I thought I better ask.

Also on a side note, be glad you have rain. Over at the ski area, it snowed all day yesterday, all night last night and all day today. they have close to a foot now.
How far up in Michigan are you?

Ariens93GT20 · May 3, 2023

Tight the lugs on those aluminum wires every year and the heat problem no longer becomes a problem. Mine have not required anything but a check for years.

Dave55 · May 4, 2023

A ground hog can go through a wood wall if it wants in. Very sharp teeth and claws. A plastic conduit don't stand a chance. Back home on the farm we had a couple buildings that had grain stored in them. Ground hogs would smell the grain, eat a hole right through a 2" thick wood wall big enough they could get in. Galvanized roofing nailed to the outside of the wall was how we stopped them. Tomorrow I will take a picture of my plastic garbage can that one decided it wanted in. Ate a hole right through it. Yes, I have also replaced conduit and water pipe that ground hogs chewed holes in. You want to stop a ground hog you have two choices, concrete or metal. If the metal is thin enough, that won't stop them either.

Alien5044 · May 4, 2023

Dave, I missed your question when you asked "Is that circuit on a ground fault breaker?"
It had a GFCI recepticle in the circuit but I removed it and disconnected all loads from the line coming from the pole and breaker box. I capped each wire in the line to test just the line itself, and it still tripped the 20amp breaker.

Sun is out today, I may try to do a little digging by the shed's slab foundation see what I can see.

Dave55 · May 4, 2023

A GFCI receptacle will mot trip anything upstream from the receptacle on the line side. It will only affect thing downstream on the load terminals. So with that being on a regular breaker, you have to have a short from the black wire to either the white neutral wire or the ground wire.
As far as rodents, mice will eat anything, squirrels are just bigger mice, rats, possums and raccoons are just bigger squirrels and ground hogs are just 40 pound mice. any of them will eat through almost anything if it is in their way or they think there is food on the other side. Install something on a nice hot summer day with sweaty hands, the salt in your sweat is enough to make them eat something. Maybe our animals are a little meaner around here, I saw goats eating the plastic fenders off a Kubota UTV on one of our job sites.

If the slab has a space between it and the ground, that would be the first place I would look. Any holes close to the wire would be my second place to look.

Dave55 · May 4, 2023

Mark, I don't remember exactly when it was that NYC had a garbage strike, but garbage was piled up 10 feet deep for half a block or more every other block. I saw Norway rats a German Shepard would run from on Broadway and a bunch of other streets. Big, ugly and almost black rats running everywhere.

MARK (LI) · May 4, 2023

It was 1981 Over 40 years ago! That one was in the Winter and lasted 16 days It was awful…. The rodent problem is so bad in the city now that a Rat Czar position has been created

Dave55 · May 5, 2023

I know some of the rats when sitting on their back legs looked over 2 feet tall. By the end of the strike I remember garbage piled up to the second floor windows in places and everything smelled country fresh, kinda like standing in the middle of a feed lot with manure two feet deep.

I just shook my head and drove on, but the piles never stopped.

Bet that rat czar is out there every day right on top of the problem.

As I used to drive around in all the big cities, they all had a trash problem.
I often wondered if the city set roll off dumpsters in an area, would the people that lived close even try to clean the place up?
I know I saw a lot of vacant lots that just had all kinds of trash piled on them, such a shame.

Alien5044 · May 5, 2023

Way back in the day, who knew this would become so relevant today?

Ariens93GT20 · May 5, 2023

Wonder if ground hogs can burp? May needs to check and see if the resident cat is capable of that before checking in on the rodent's sweet tooth.

Dave55 · May 5, 2023

If you are going to sic a cat on a ground hog, it better be a mountain lion.
A house cat, that ground hog will be having cat for supper.

Lost all power to the shed

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