my electrical box EXPLODED!!!

[dpb]

MiamiCuse wrote: ...

...

Well, from just looking my first suspect point would be the red/black/white set coming from the upper right across to the other box. It looks like they have been pulled tight leaving no slack at all and are possibly rubbing against the connector. I can't tell for sure even where they're going--they're hidden behind the other bundle too much to trace.

I don't think in that configuration you can see enough to tell.

It does look to me like all three there show signs of heat--particularly the white, of course. Don't know where they're coming from, but I'd be for getting some slack in there so could really tell--just don't think it's possible as is.

It also looks like there could be a potential problem brewing at the upper right where they come into the box--they're pulled tight at that corner, too.

I'd say the other potential culprit might be the yellow going out.

I'd surely like to have known what was actually going on when it occurred--I still can't rule out from the looks of it that a hot end from somewhere else entirely got flipped across there from the way it looks--

I agree you have a problem that needs investigation to unravel what happened--I don't think the whole house wiring would need redone but I'd surely be doing some fairly major effort to get enough slack in that box to investigate it and to leave some slack in that one set that don't have enough.

It's useful to see the picture, but certainly not conclusive other than there definitely was an event at that point.

--

[dpb]

dpb wrote: ...

...

As a solution, one might at least consider pulling the branch circuits from the two upper entrances at this end and making new runs from here to the next box. Depending on where they're going, that might not be particularly difficult or expensive.

As noted, I do not at all like that cross-box pull that certainly appears in the picture to have been pulled really tight (unless, of course, it's been pulled on only temporarily for some reason during the rework, perhaps, but if so, it needs the slack back). If it really is as tight as it looks and there is no slack while I was in major rework I'd surely consider it a candidate for a new run to forestall a problem. Depending on what I saw w/ "hands on", I might be satisfied w/ a non-metallic bushing to protect the insulation on the corners if inspection indicated it isn't damaged already.

--

[dpb]

...

I'm delaying some office work and that is delaying mowing... :)

I looked at the wider-view picture again...that was actually quite a spark it seems when I realize the marking covers the full quadrant essentially.

It is, however, essentially symmetric around the SE of the conduit and also seems as though there's a concentrated mark on the NW edge of the center knockout plug. Behind that section is where it happened almost certainly imo, now. Notice how it appears to be evenly spread behind the wires and the clean spot where the red protected the surface and looks as though it has been moved in your investigating. The discoloration of the three wires there is telling too, I think. Will it come off? The white certainly seems to show a couple of at least knicks although don't look to be serious kinda' looks like been handled w/ pliers or pushed on w/ screwdriver or similar abuse...

I'm still thinking you're going to have to have more slack to be able to see what's behind there than can as it is in order to find the actual point unless, as I keep harping on, it was a bare hot end from somewhere else that just got lucky and hit the connector/box at that area.

Did it trip a breaker? That would give a circuit, too.

My prime suspect is still that diagonal run through although I can't get past the idea of the electrician holding a hot end...

This will be most interesting when you do finally track it down...

--

[MiamiCuse]

Thanks dpb for all your comments. I am going there tomorrow again to untangle the boxes and see if I can get some slack in the wires in order to see what I needed to see. I will report back with good news hopefully or bad news.

Now go mow your lawn!

MC

[MiamiCuse]

OK repair is done. You are right dpb, the spark came from an old wire going to the conduit in the back of the box, it was a solid wire going to a well pump, and as I loosen and untangle all the wires it literally broke off.

I believe my electrician when he tried to figure out which wire goes where, he used the "pull" technique to pull a wire hard and see which wire moves on the other end, and that caused a big strain on some wires, especially with that conduit having so many wires going through,

So here is the box taken apart we can see the charring:

and the connector around that hole see it's totally broken by the spark:

and now, I have two new boxes, with two connectors between the boxes instead of one and there are more slack to the wires.

Thanks for all your help dpb.

MC

[dpb]

MiamiCuse wrote: ...

It pretty much had to be there based on the markings -- that chunk it vaporized out of the connector was a pretty good hit...bigger than I expected, even.

But, all's well (so to speak :) ) that ends well and there's no mystery in the end (and old wires _don't_ just do that :( ).

--

[Tony]

Wires installed in 1972 are not so old as to require replacement. However, it sounds to me like the wire was damaged where it entered the JB, probably when it was originally installed. It is not normally possible to cause a short just by brushing against a wire. So, I would suggest, absolutely, that the cause of the short should be determined, and that wiring, at least, should be replaced if necessary. The black carbon deposits should make the location of the damage rather evident. One might be suspicious of the quality of other wiring, particularly with regard to splices and abrasion. This would require an inspection of all, or at least a reasonable sample, of the device and junction boxes, and perhaps an insulation test.

** Posted from **