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BobJones · 10-01-2018, 07:04 PM

Hi guys!

I'm helping my parents with some aspects of their house. They are getting a new glass sliding door installed and as a result some wires need to be re-routed. When I cut into the drywall to expose the wires I found some discoloration that leads me to believe the wires were either hot or tried to burn.

I don't know if I might be worried about nothing or if the marks do indicate a problem?

Anyway, here's some photos of what I found. Any ideas or thoughts would be appreciated!

powercat_ras · 10-01-2018, 07:10 PM

Sure it's not just spray paint on the plastic covering?

BobJones · 10-01-2018, 07:14 PM

No, it's not paint. The odd thing is the discoloration happens between the studs. Thinking perhaps it was moisture or something I examined the empty voids carefully and there is zero moisture in there.

The entire circuit is on a 15 amp breaker. It power the ceiling fan/light, a clock radio, two 100 watt lamps and a cordless phone as well as a bed warmer. As far as I can see that's all that's on that circuit.

I'm at a loss as to whether the wire is heating up in places and trying to burn or whether the discoloration is from something else?

swampdog2 · 10-01-2018, 07:21 PM

Best way to find out is turn all that on while you have the wire exposed and see if it starts to feel real warm to the touch ? might be a good time to replace it with a larger size wire

Solo_RV_Guy · 10-01-2018, 07:35 PM

Quote:

Originally Posted by swampdog

Best way to find out is turn all that on while you have the wire exposed and see if it starts to feel real warm to the touch ? might be a good time to replace it with a larger size wire

He has at most a 4 amp load on that circuit. It should not be getting hot or even warm to the touch.

Solo_RV_Guy · 10-01-2018, 07:37 PM

Quote:

Originally Posted by BobJones

Hi guys!

I'm helping my parents with some aspects of their house. They are getting a new glass sliding door installed and as a result some wires need to be re-routed. When I cut into the drywall to expose the wires I found some discoloration that leads me to believe the wires were either hot or tried to burn.

I don't know if I might be worried about nothing or if the marks do indicate a problem?

Anyway, here's some photos of what I found. Any ideas or thoughts would be appreciated!

Replace that wire. There is likely internal damage or lack of insulation that is causing a partial short (not enough to trip the circuit breaker but enough to get hot.

60sumtin · 10-01-2018, 07:46 PM

Is it copper wire or aluminum? If its 14 gauge copper its an appropriate size for a 15 amp circuit. However if its 14 gauge aluminum its under sized for a 15 amp circuit. Aluminum wire can also be easily damaged during installation which can cause overheating at the damaged spot. The 2nd photo looks to be burned on a kink which is why I make the comment. Can you tell us what gauge wire it is and if its aluminum or copper?

rcflyer1201 · 10-01-2018, 07:50 PM

Why would they be using aluminum wire?

BobJones · 10-01-2018, 07:51 PM

It is copper wire but I cannot tell you what the gage is right now (not at the home). The concept of it being burned on a kink sounds about right. It fits with the location of the burns.

If replacing the wire do you mean the entire run? Ie, the entire circuit?

powercat_ras · 10-01-2018, 07:57 PM

Bottom line since you are extending (relocating) that wire run just be safe and go ahead and replace that section. Once you have replaced it you can slice open the discolored section and see what the wires and insulation look like. Even at full rated load a properly sized residential NM cable (Romex is a brand name) should not increase temp more than a couple of degrees F. Only exception can be if a large # of NM cables are tightly bundled together in a enclosed space which is not supposed to be done.

60sumtin · 10-01-2018, 08:07 PM

Quote:

Originally Posted by rcflyer1201

Why would they be using aluminum wire?

It was often used in homes built in the 60s as a cost saving measure because copper at that time was expensive. The only time I've come across it up here is when doing renovations in older mobile homes manufactured in the US and exported to Canada.

BobJones · 10-01-2018, 08:07 PM

The line does need to be extended as the routing makes it too short. It appears to run between two outlets so my guess is that section might not be too hard to replace although we would have to do more drywall work. My thinking is that perhaps we should follow it the the next outlet and take it off there and run a new line between the two (that's where the line came from).

Rodg495 · 10-01-2018, 08:08 PM

I agree it needs to be replaced. You can replace from one junction box to the next. Or you can add a new box at that location and pull new wire from whichever directions is the easiest. That old wire could have been kinked at one time prior to it's installation and is probably broken inside. Open it up after you take it out. Remember, you cannot 'splice' or repair it at that location unless you put in a new junction box ( new outlet ) accessible. No hidden splices or boxes inside the wall.

BobJones · 10-01-2018, 08:25 PM

Quote:

Originally Posted by Rodg495

I agree it needs to be replaced. You can replace from one junction box to the next. Or you can add a new box at that location and pull new wire from whichever directions is the easiest. That old wire could have been kinked at one time prior to it's installation and is probably broken inside. Open it up after you take it out. Remember, you cannot 'splice' or repair it at that location unless you put in a new junction box ( new outlet ) accessible. No hidden splices !

Thank you all ! The more confirmation the better I feel as I'm not an electrician. Also, thanks for mentioning it has to have a junction box if it's to be cut and joined. The worst of the 'burning' is well into the hole in the next stud. As such, you could not even cut it there.

However, the next outlet that that damaged wire will run to is only about two feet away on the next wall. So I think the smart move would be to cut more drywall, expose the next outlet, take it off of there and then replace the entire run between outlets.

I just hope the whole house is not full of half-burnt wires like that. The house was built in the 90's and is otherwise a quality home.