[superoxide]

The breaker in our house that feeds our storage shed has been tripping since we moved here a few years ago, which I'm guessing is due to a nicked wire or short somewhere in the buried line. Sometimes the breaker won't trip for a few days (and the power works in the shed), other times it trips almost immediately, usually after some good rains.

However, my question has to do with some odd wiring in a fused safety switch box located in the shed. An annotated image of the box is attached. What I really don't get is how in the world can there be a closed circuit when it's wired this way? Again, there is power in the shed when the circuit breaker in the house ins't tripped. Perhaps the breaker tripping has to do with the way this box is wired? At the moment the breaker is tripping immediately, so I can't put a meter on the input wires to test which is the hot wire (I know it's supposed to be black, but that wire isn't hooked up to anything).

Do you have any suggestions on how the box should really be wired? E.g. should I connect the ground to the unused pigtail? Or is there an alternative to using this safety switch box? I'm really not sure why it's used in this application.

My inclination is to re-wire the box with how I think it should be done (or hire out a certified electrician), but wanted to check here first to make sure I'm not missing something. Thanks.

 

[jmon]

You say it happens especially after a hard rain, check your outside gfci, water and moisture are getting in somehow causing the tripping. Replace gfci if needed.

Get some caulk or a new outside Waterproof box if needed. See if that helps. Just a suggestion.


An electrician will be along soon and check your inside box.

 

[CodeMatters]

Appears they did everything wrong. The white cable appears to be basic
romex, what we'd call NMD-90 up here. If that's what it is and it's buried
from the house, that could be part of the problem as it's not rated for
wet or underground.
Might be easier to rip it all out and start over than to fix.

 

[bfrabel]

I agree that it would definitely be best to start over. As best as I can tell from looking at your pic, the only thing that makes sense to me is if that white wire going to the top of the disconnect is actually a hot. Yes, continuity could be normal between a hot and a neutral when you turn on the switch. What could be happening is that you might be reading the resistance through the light bulb or other loads.

With my theory of the white wire being hot, I'm thinking that the black wire might also be hot, as in a 230V circuit. Have you checked it? Is the breaker in your house that goes to this thing a single pole or double pole?

If it is hot, you need to tape it or wire nut it or better yet, disconnect it from the breaker in your house. This could be what is shorting out. Maybe the with the rain comes more humidity, which is what makes it short out easier.

 

[superoxide]

Thanks for the replies so far. I forgot to mention that the GFCI outlet is located inside the shed, so that's not the reason for the tripping.

But, after a little investigation I've found the following:

1) indeed, the white wire is hooked up as the hot wire inside the house (3rd breaker from right in the first photo below). I was able to verify this by getting the breaker to stay untripped long enough to test at the switch box inside the shed. Though, my meter measured it as -120V when touching the positive electrode from my meter to the white wire and my negative electrode to the ground/neutral. Not sure why that would be the case.

2) the ground wire is serving duty as the common (neutral).

3) the black wire is not hooked up inside the house, or in the shed (photo below).

4) at least the installer (I'm guessing a DIY project here) used UF wire. HOWEVER! It is clearly not the same wire that exits from the house. The wire in the shed is whitish, inside the house it's gray and has different markings. I smell a splice somewhere in the line buried underground.

A couple of questions, if you don't mind:

1) Should I just rewire it properly with the existing wire and see if that fixes the fault? Or should I just replace the whole line now?

2) If I use the existing wire and hook it up correctly in the shed, would it be okay to mix the common (white) and the ground in the same bar at the breaker box in the house?

Thanks again!

 

[bfrabel]

It would be better to make the white wire a neutral and the black wire a hot if possible, while keeping the ground wire as a ground.

My guess though would be that this is how it started out, but then the breaker started tripping and then they came up with the idea to rig it up like it is now, and now that's not working anymore either.

Do you really need power in this shed? If so I highly recommend that you start over and figure out how to do it the right way, which might mean some blisters on your hands and a sore back are in your future.

 

[Datawise]

I suspect that there is a separation in the black cable (wire) and they used the bare (bond) as a neutral and the white as a hot.

I would guess now that the failure (separation) or damage is shorting out the hot (white) and the neutral (bare).

Sounds like a case of digging it up and starting over. Install some conduit and some proper underground rated wire.

Cheers
John

 

[superoxide]

It would be better to make the white wire a neutral and the black wire a hot if possible, while keeping the ground wire as a ground.

My guess though would be that this is how it started out, but then the breaker started tripping and then they came up with the idea to rig it up like it is now, and now that's not working anymore either.

Do you really need power in this shed? If so I highly recommend that you start over and figure out how to do it the right way, which might mean some blisters on your hands and a sore back are in your future.

I suspect that there is a separation in the black cable (wire) and they used the bare (bond) as a neutral and the white as a hot.

I would guess now that the failure (separation) or damage is shorting out the hot (white) and the neutral (bare).

Sounds like a case of digging it up and starting over. Install some conduit and some proper underground rated wire.

Cheers
John

Thanks. I came to the same conclusion and started digging at the house and shed tonight. It turns out they had used metal conduit with just a short elbow at each end. I also found the first of at least two splices in the old line, which came back above ground with the splice tucked under the deck before going back below ground at some point. This first section of splice is different wire (NM) than what comes from the house or ends up in the shed. I really wasn't looking for the splice, as I plan to abandon the old line, but I just came across it.

Wire nuts and electrical tape are all you need to make a good outdoor splice, right? I will never under stand this "good enough" approach, beyond a short term patch. Either fix it right or not at all.

 

[surferdude2]

I dare say it probably wasn't down 24" like the code requires, unless it's in conduit, which only need be 18" deep.

I don't envy you the new trenching if you decide to replace it. That doesn't look like good digging soil, not that such ever existed.

 

[dmxtothemax]

So many problems !
are you sure that starting over again would not be a better option ?

 

[Wiredindallas]

For outdoor splices use wire nuts with silicone (the blue ones).

 

[surferdude2]

I dare say it probably wasn't down 24" like the code requires, unless it's in conduit, which only need be 18" deep.

I don't envy you the new trenching if you decide to replace it. That doesn't look like good digging soil, not that such ever existed.

Just to add another option, you could go with rigid metal conduit and be in compliance at 6" deep unless it's where it can be driven over, then it needs to be 18" down. I always used RMC when I had to do my own digging. :wink2:

 

[seharper]

4) at least the installer (I'm guessing a DIY project here) used UF wire.

Yeah it's plainly UF wire. That is white. Not what I'd expect but you learn something new every day!

1) Should I just rewire it properly with the existing wire and see if that fixes the fault? Or should I just replace the whole line now?

Meh, I would hold off until you have finished mapping it and testing it. There might be something stupid/easy they didn't have the patience to solve. They did use the right wire, not complete morons.

2) If I use the existing wire and hook it up correctly in the shed, would it be okay to mix the common (white) and the ground in the same bar at the breaker box in the house?

The neutral always goes on the neutral bar. The ground always goes on the ground bar. Only in the main panel (first stop past the meter) can they be the same bar.

I suspect that there is a separation in the black cable (wire) and they used the bare (bond) as a neutral and the white as a hot.

And they wouldn't have done that for no reason. They were clearly having a problem somewhere. Keep hunting. If you can find that last splice, you might hit paydirt and be able to salvage the wiring run.

Thanks. I came to the same conclusion and started digging at the house and shed tonight. It turns out they had used metal conduit with just a short elbow at each end.

Yeah, that's mandatory for physical protection of the wire, down and around the elbow, then you can go direct burial. YOu do not need to meet the conduit fill rules, so if it fits, it ships.

But you're not supposed to use EMT lol.

Wire nuts and electrical tape are all you need to make a good outdoor splice, right? I will never under stand this "good enough" approach, beyond a short term patch. Either fix it right or not at all.

It'll work for a week lol. I think shortcutters' motivations is "too many things on the honey-do list" ...

Just to add another option, you could go with rigid metal conduit and be in compliance at 6" deep unless it's where it can be driven over, then it needs to be 18" down. I always used RMC when I had to do my own digging. :wink2:

Oh yeah, fantastic stuff. Price is insane but you get to trench it with a garden trowel

I think Rigid needs only 12" under vehicle routes, could be wrong.

Also, OP, a single 120V circuit that is GFCI protected can be direct buried to 12". So if this is too shallow for the 24" direct burial requirement, slap a GFCI on the supply side (inline recep, deadfront or breaker, QO breaker ouch) and you're G2G. Assuming you can make the hard-to-replace section work properly.

 

[surferdude2]

Burial Details

(No pun intended)

 

[superoxide]

Thanks to everybody who helped with my question. I ran a new UF line over the weekend. Buried it 12"+ deep, which I confirmed is code for my application. I also added a GFCI before the line leaves the house. It's installed and working as intended, although I have some landscaping to touch up (I really dislike loose rock landscaping!).

For what it's worth, I came across the old line while trenching, which was 3" deep, at best. Hope the new line lasts well after I'm gone!