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Scary wiring

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crueby:
Yesterday one of the three 120V/60 watt bulbs in the hanging fixture over my kitchen table blew,

so I removed the fittings and the glass panel at the bottom to get access inside to change the bulb. What I saw inside was pretty scary. This fixture was installed in 1985 when the house was built, and gets a LOT of use, on most of the day/evening. Being mostly enclosed, it does get fairly warm but not hot, like a warm cup of coffee. Apparently that heat was enough over the last 40 years to cook the oils out of the plastics in the wire insulation and the wire nuts. Here is what they look like after I removed them (was able to find a replacement 3-bulb fitting that was the same to replace it with)



As you can see, everything disinigrated as soon as I tried to un-twist the wire nuts! Those yellow bits that look like a crushed cracker used to be the wire nuts, you can see the tapered spring from one at the lower center. The black bits used to be the insulation on the wires, that are now totally bare! When I went to take it apart, the insulation was still on the wires, but with cracks everywhere. The wire sitting left/right was the ground wire, it was not insulated, but the other things that look like tree roots are the wires.
REALLY glad I didn't poke anything when it was on, or it likely would have shorted out. Yikes!!   :zap:    :paranoia:

Just finished taking it all down and rewiring it to install the new bulb holder, should be good for a couple more decades. The fact that the wires were above the bulbs inside the shade and glass diffuser meant that things got warmer than they ought to, not a great design!   :hammerbash:

The reason I am posting this is as a warning - go look around at your light fictures and see if you have any with a similar setup, if so open them up and have a look at the wiring! It was fine for nearly 40 years, apparently recently it all got to the point where the plastics started to fall apart. Glad I caught it before anything bad.

cnr6400:
 :ThumbsUp: :ThumbsUp: :ThumbsUp: Glad you caught that one in time. I found similar light fixture issues in our 1983 built house. To be safe I replaced them all. At the same time I checked all the Romex wiring to check that its' insulation was not damaged in a similar way to the fixtures, and thankfully it was all OK.

Just a side note re brand new made in far east  fixtures from the big box DIY stores - many of the fixtures I have seen recently had very low quality fine gauge connection wire, and really poor wire nuts - some broke in half with finger pressure. A friend bought a new one recently that had connection wires break off while installing it - the wire was copper coated aluminum stranded wire that was very brittle. T here used to be several agencies here in Canada inspecting imported electrical equipment to keep unsafe stuff from being sold, but I don't think anyone's minding the store anymore.  :shrug: Be vigilant!

Roger B:
The design life of PVC wiring and plastic components is 40 years at maximum temperature. In normal domestic use components rarely reach maximum temperature so a much longer life span can be expected, however that is not always the case.

As an aside automotive cables have a design life of 3000 hours at rated temperature based on 100 000 miles at an average of around 30 mph.

Plastics do not last forever  ::)

CI:
Incandescent bulbs are bad about overheating wires and sockets.
The new 3,500 k color temperature LED bulbs run much cooler, and have the same color as incandescent bulbs.

I have replaced most (but not all) of the light fixtures in my house, and I have noticed the same thing, ie: dried out wiring that is brittle.

Light switches in my house are on the list of things to be changed.
I have changed some of them already that are in high traffic areas, but I need to change all of them.
The switch mechanism gets loose and mushy, and the will eventually start arcing due to a poor contact.

And last on my list is 120 v receptacles.
They also wear out, and the contacts get loose.
I have replaced a few, but need to replace them all.
The push-in wiring style should never be used on receptacles; wrap the wire around the screw and tighten it firmly.

I replaced my electrical panel, and all the circuit breakers.

Luckily my wiring is good quality Romex (tm), and it has a ground wire.
I have seen some houses build in the early 1950's that did have Romex, but the insulation had become dried and brittle, and so any wiring that is disturbed just cracks off the insulation (time to rewire the house when you have this situation).

I have friends who have the most worn out extensions cords you can imagine, with all sorts of tape, etc.
I never let an extension cord get worn; I will toss it immediately.
And I use #14 AWG minimum for all extension cords, with ground.
For heavy loads, I use #12 AWG.

.

uuu:
I've not found any degraded wiring in my UK house.  We run on 240V, so half the current - perhaps that's the key.

Anyway, I've gone to LED units now.

Wilf

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