my electrical box EXPLODED!!!

I was in the process of rewiring over 60% of my house and finally all rewiring are done. Yesterday was the finishing aspect for the electricians to do an electrical panel schedule - I have two separate panels A & B and they needed to mark all the circuit breakers existing and new as well as mark on each box/device which panel/circuit they belong to.

So as we were labeling one of the junction boxes were opened with some old wires in them, they had it all "stretched out" in order to figure out which wire goes where.

When one of the walked by the hallway where the box is with wire sticking out, he brushed his shoulder against some wires and suddenly BOOM!!! I heard a small explosion. The junction box is now partially black and this is what he called a "home run" connecting wire to the panel and running to another box.

The wires in the box "appears" to be ok to me. The electrician told me I should consider changing all "old wires" since they are old (1972) and may be the cause of the problem.

Replacing ALL old wires are cost prohibitive. What is the best way to determine why I had an explosion? I cannot see a wire being messed up as a result of the explosion...

and I could not tell if he said it just for me to hire him for another few weeks.

Thanks,

MC

Reply to
MiamiCuse
Loading thread data ...

MiamiCuse wrote: ...

...

There must be an arc mark on the wire where it came in contact w/ the panel to cause the short to determine where the problem came from.

The root cause could have been anything from an exposed end, a nicked spot from previous work or a break from having become brittle either by age or perhaps some overheating w/ time.

I'd examine several of the old wires and see if there are any signs of cracking and whether the insulation does break w/ flexing and whether it is hard and breaks when stripped.

If these guy(s) are reputable (as one would assume they would be since you hired them based on qualifications and reputation, right? :) ), you're paying for advice as well as service.

The additional cost of rewiring would be minor in comparison to the cost of a fire later, though. The age you're talking isn't _that_ long, but w/ as much as you're investing already, cutting corners here isn't real smart, either. It's a tough call remotely...I have no "up/down" call here, only to not make the decision purely on trying to save a buck but on what seems the right thing based on what you can determine.

There's always the outside consultation of another electrician not associated w/ these contractors route if you're uncertain...

--

Reply to
dpb

Thanks, I guess my uncertainty came from the fact that it happened at 5pm yesterday and close to the end of the day, I would expect them to at least investigate which wire caused the problem and then offer an informed recommendation.

But he just glanced at it and said "these are old wires they do things like this if it were my house I will rewire all old wires just to be sure..." I mean this new wiring lasted about several weeks and part of what they told me they would do is to replace old questionable wires as they go, but they never did and now at the end of this they recommend that I replace ALL old wires because of this, so why didn't they recommend this along the way?

May be I need to hire another electrician for a second opinion. The problem is the answer to "should I rewire all my old wires" is probably going to be "of course new wires will be better than old wires" and "I cannot tell you unless I pull them all out..."

MC

Reply to
MiamiCuse

MiamiCuse wrote: ...

I'd not put too much into the first off-the-cuff comment--as you say, it's more reaction than analysis.

I'd definitely go inspect the wiring myself -- one should be able to tell where the arc happened and perhaps see why as noted.

If the insulation is extremely brittle (cracks simply w/ a bend, for example) that's pretty self-determinant that it's a potential problem down the road. Then you can have the discussion of why they didn't do what they said.

The hard part is if it isn't so clear-cut as it probably will be...I'd still do the investigation and at least know whether I thought it was a fluke, something as clearly expected because an exposed end did contact the panel or an obvious nick that was mechanically caused, or the insulation does actually crack/break easily. If it's a clear cause, you can probably relax. If it's clearly that the insulation is failing, well, it's only money. If it's in between, again, you're needing a decision that nobody here can really help...

That's repeating the same answer in different (or sometimes the same, even) words, I know... :)

--

Reply to
dpb

I concur with dpb. 1972 wires are not that old. There are plenty of houses wired in the 40's and 50's that are still using the original wiring. One of the hot wires may have had the insulation nicked and by moving it the exposed copper may have shorted to ground. You should take a look yourself with a magnifying glass and a flashlight. Look at the individual wires and try to determine at what point along the wire did it short out. Was it close to where it entered the box or at the end of the wire? Did it short to the box, the neutral, another hot wire, or to a ground wire? You should also check to see how pliable the insulation is on all of the wires. If the insulation is brittle and cracks or breaks off, then you should consider having that circuit replaced.

I am assuming that your house has copper wiring and not aluminum. Aluminum conductors can easily break after bending a few times.

If the wire shorted out close to where it enters into the box, the conductor may have been damaged to the point where copper may arced off of it and there is not enough slack to strip it back to splice further down. It is remotely possible that there may be slack in the wall that can be pulled into the box, but the clamp or connector will need to be loosened and staples may have to be removed which will involve making a hole in the wall.

What brand of circuit breakers are you using?

Reply to
John Grabowski

dpb wrote: ...

The one thing (obvious, probably, but...) is if you're not sure and they're still saying "replace", ask them/him to show you what, specifically, it is he sees that indicates to him it needs replacing.

--

Reply to
dpb

It seems to be broken.

Reply to
Stephen King

MAY be the problem? A several-thousand dollar renovation for something that MAY be a problem?

What if you run all new wires and the boxes STILL explode? What if it turns out that a twenty-five cent mousetrap would keep the critters from gnawing the insulation?

No, find out the CAUSE before you invest in an expensive cure.

Reply to
HeyBub

I think you should change all the "old wood", since it is old (1972) and may have problems. After all, the trees the wood, the 2x4's that make up the frame, was made from trees that would be dead by now if they hadn't been cut down for lumber. Dead trees are unreliable.

When you find an electrical problem, fix it. Brushing by and touching wires that are sticking out of the box doesn't count as a found problem to me, but as a created problem.

ALL the old wires are not the cause of the problem. At most, ONE of the old wires is the cause, and maybe not even that many.

Reply to
mm

Why were wires sticking out of the box? Doesn't seem like something a competent electrician would do. Seems to me common sense would be not to have wires sticking out that could come in contact with somebody. to me any damage would be on him, he assumes quiet of liability as a contractor.

If they think the wires should be replaced I would ask what they base that opinion on. Copper last a long time if your wiring is copper. There's houses still using knob & tube think how old that is.

,

To me it's sounds like he is trying to ding you for more Money. This is how a lot of contractors operate they come in get your trust sound very convincing and then start suggesting other should be done items. On that same subject is he a licensed contactor? Did you check the status of his contractor's licenses? Did you check to see if he has liability insurance? ( that's a biggie)

Reply to
Sac Dave

I examined the wires in that box closely, and I did not see any exposed copper at all, which is troubling. What is even more troubling is that there is no wire that is charred, only the box.

Of course, there are three boxes near to each other, one box on the left, one box on the right connected with a box coupling, then behind the box on the right is another box facing the other side of that same wall, so those are three walls with wires running into out of each...120v, 220v both. I will take another look at it again tomorrow.

Reply to
MiamiCuse

Circuit breakers are all GE.

I cannot see the nick, but I will take a closer look tomorrow with a flash light as you suggested. Thanks.

I have twisted, bent those wires myself, does not look like there is any danger of breaking off.

Reply to
MiamiCuse

Hey MC, I 'd think about replacing the electrician before replacing all of those 'old 1972' wires. It sounds too fishy that he brushed up against a wire and it shorted out while you were there.... It may just be that a wire nut that is used to make an electrical connection was installed incorrectly, leaving a little bit of a hot wire exposed and it shorted to the junction box. Or he could have also staged that to get more work out of the job. I had wires from the 1920's that were still fine. Eventually the insulation of this old wiring does become brittle and crack. But this was cotton and rubber on mine, yours is much more modern plastic and lasts longer.

Get another opinion. Mark

Reply to
mark

MiamiCuse wrote: ...

...

I wouldn't expect "charring" from a momentary arcing but there's definitely something in the vicinity that could have touched at the point indicated on the box.

Not being able to see it, no real specific ideas but is it possible the electrician was carrying something (like a roll of wire) and it brushed a hot point rather than it being the wire in the box at all?

--

Reply to
dpb

This comes back every few months; find a new place to tell your lies.

Reply to
TWayne

he is ok.

we are now basically done with all wiring (new ones), and many of the boxes have wires coiled in them with the mud rings installed, and waiting for drywalls to be done before switches, outlets etc... are installed.

since it will be at least a few weeks until drywall, I don't want to call them a month from now and find out they have left town or whatever (they told me business is slow and their owner is selling the biz as RE gets really bad in south Florida), I told them to label everything on the panel and each device, and I know this outlet goes to electrical panel B and circuit 18 etc... and in cases the junction box has multiple devices (fan, light, three ways, etc...) to label each accordingly, so that is why they had quite a few junction boxes open and some wires "untangled" so they can label all of them, new and existing.

It was not really an explosion like things blasted into pieces, it was a pop sound and part of the 1900 box is now dark and burnt. I will examine closer to see if I can identify the exposed portion that caused the problem, there has to be some exposed copper somewhere in that box that caused this.

Reply to
nmbexcuse

I am confused, are you saying I made all of this up to waste my time to post and everyone's time to read?

Reply to
nmbexcuse

Well I looked and looked and could not find the wire that is responsible. I expected one wire that has the copper part exposed but after looking very closely I was unable to identify anything. Here is a pic:

formatting link
The box to the right, on the upper left corner see the blackened area? That was caused by the spark. A closer look:

formatting link
I examined each wire there, and did not see anything. Is it possible the exposed wire is actually inside the pipe behind the box and when pulled caused the spark?

Thanks,

MC

Reply to
MiamiCuse

Anything is possible..it looks if the black wire has been "burned". What I'd do is shut off the power, then remove the right hand box and all it's conduit connections and the box also. You'll get a lot better look at the wires that way.

Can you access the wires at the "other end" of that conduit coming from the back of the box ? You might be able to get some "slack" so you could pull them out a couple of inches to better inspect them.

Make notes to go with your digital pic to ensure you get it all back together correctly

Reply to
Rudy

My best guess from the picture is the red or black wire coming from the upper far right conduit, assuming those head upstream toward the incoming power. the charring looks like that is where the arc was. A nick or fatigue crack in the insulation being opened by the wire flexing would do it. Do those conduit ends have any sort of bushing on them? With the power off, stick your finger in there and feel for burrs. They were working the box with a hot feed coming in to it?

When I replaced the outlets in this place, several boxes had minute stripping-knife nicks in the leads, from where the last guy had cut away the outer sheath of the romex. They showed up as copper glints under my flashlight. Luckily, they weren't deep, and a little electrical tape solved the problem.

-- aem sends...

Reply to
aemeijers

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.