is this a burn mark on the cable? (does it need to be repalced)

[bio mass]

This is an old NMD cable with a rubber sheath and paper insulation. It is 60 years old. I am going through a renovation and i was checking the cable coniditon. It previously had a clamp on the end. I removed the clamp. I cut off 1 or 2 inches off the rubber sheath to get a closer look under the clamp to see if any damage was done. I noticed the neutral wire has a bit of browning on it (see picture). I dont know if the stain is from the paper or a burn mark.

The only reason why i am hesitant to replace it, is the location is a little difficult to access but it can be done if necessary.

what is your experince in these type of matters? I will replace the cable is this is not safe. yes i put the electrical tape.

i cut of a very tiny amount of plastic on the hot wire by mistake and got some caulking on the neutral, also by mistake. it is a sign from the electrcial overseers i think.

 

[K8MHZ]

That's what tape is for.

 

[bio mass]

That's what tape is for.

tape under the new locatino of the clamp or on the browned area?

 

[480sparky]

Is it brittle or hard at the discoloration?

 

[bio mass]

definately not birttle. as far as "hard", i was just trying to scrape with my fingernail. it is really tough to say for sure as the the plastic in non-brown areas is sort of hard. I thought i was just felling the slight imprint from the clamp. I did not bend the wire at that location have attached another photo with better lighting.

 

[Little Bill]

Looks more like a stain than a heat mark. But you could add some tape for peace of mind.

 

[gadfly56]

Looks more like a stain than a heat mark. But you could add some tape for peace of mind.

I agree, and if you look at the hot next to it, you can see compression marks that match the "stains". I don't think it's anything to worry about.

 

[winnie]

Even if the cable is in good enough condition to last for another 20 years, you might consider that it doesn't have and EGC and it is 60 years old, and bite the bullet to do the replacement.

Part of this assessment is what sort of load is being served by the cable. A single light fixture embedded in a ceiling, or a receptacle circuit?

-Jon

 

[bio mass]

I am not sure how many circuits it is serving,(if it is the end of line or not). I thnk there are too many oulets on the circuit by today's standards. It goes through an attic, i think to a light fixture switch (it passes in the direction of a fixture, that i know for sure). The attic is difficult to get in and out of. The room has been renovated twice in the past 10 years (different items addressed) and those other new cables have a ground. I think it was taken from a nearby bathroom?. this is not really a questino of biting the bullet. I would just do it. it is a little more difficult during the covid time. at least here. that is the main barrier. But if it was unsafe, then i would bring the EC in and take care of the rest

 

[480sparky]

I am not sure how many circuits it is serving, but I think it is too many by today's standards. It goes through an attic, i think to a light fixture switch (it passes in the direction of a fixture, that i know for sure). The attic is difficult to get in and out of. The room has been renovated twice in the past 10 years (different items addressed) and those other new cables have a ground. I think it was taken from a nearby bathroom?. this is not really a questino of biting the bullet. I would just do it. it is a little more difficult during the covid time. at least here. that is the main barrier. But if it was unsafe, then i would bring the EC in and take care of the rest

Um.......... one black and one white wire can only serve one circuit.

If you mean it serves too may devices..... there's no Code for how many devices a general purpose circuit can serve.

 

[winnie]

I believe that your original question was answered: were you looking at a burn mark. Nope.

Is it unsafe is a harder question, because once you have something that is aged but appears to be in good condition, does not meet modern code but was installed in a acceptable fashion at the time... you are now asking about probability and risk.

It it as safe as a modern installation? _No_. It is not as safe as it could be.

Is it so unsafe as to present an immediate hazard with no question of needing to be replaced? IMHO no, but I can't honestly make that call without tracing the circuit out and seeing what else is there.

In my own home, if this cable was supplying power to a series of receptacles, I would replace it so as to have proper grounded receptacles. However if this cable was supplying power to a light fixture, or was part of a switch loop for a light fixture, then I'd let be. Note: if it is supplying a light fixture I would look _very_ closely at that fixture, since the heat from lamps degrades the insulation. The wire might be fine at one end and in horrible shape at the lamp end.

-Jon

 

[bio mass]

Fortuantley the light fixture has alwways been a chandelier. I think it has been like that for decades. It sounds like i need to take a trip to the attic to see if it is at the end the circuit. Dang.

 

[Beaches EE]

Technically, I believe, if one is going to install a replacement light fixture then the cable should be rated according to the fixture label and is often 90 degrees C. If accessible, then a junction box with a short length of new cable to the ceiling outlet box might work.

 

[bio mass]

I believe that your original question was answered: were you looking at a burn mark. Nope.

Is it unsafe is a harder question, because once you have something that is aged but appears to be in good condition, does not meet modern code but was installed in a acceptable fashion at the time... you are now asking about probability and risk.

It it as safe as a modern installation? _No_. It is not as safe as it could be.

Is it so unsafe as to present an immediate hazard with no question of needing to be replaced? IMHO no, but I can't honestly make that call without tracing the circuit out and seeing what else is there.

In my own home, if this cable was supplying power to a series of receptacles, I would replace it so as to have proper grounded receptacles. However if this cable was supplying power to a light fixture, or was part of a switch loop for a light fixture, then I'd let be. Note: if it is supplying a light fixture I would look _very_ closely at that fixture, since the heat from lamps degrades the insulation. The wire might be fine at one end and in horrible shape at the lamp end.

-Jon

i checked the circuit and created a diagram. currently the outlet in question does serve other 4 other plug outlets in the same room. . upstream: the cable goes to a light fixture with 2 other old rubber cables in the attic, totaling 3 rubber cables in the upstream junction from the recepticle. those can be replaced too, but alot of work. i fear a can of worms here. i have figured out where the cable can be disconnected in the future at the light fixture and replaced with a new cable to the panel. that will be alot of work, but it can be done.

It is part of a switch loop, but the light fixture box goes to two recepticles, not just the one. One upstream and one downstream (recepticle in quesiton)

regarding the recepticle in question, it is not grounded by its own conductor (two wire), but there is a ground there, borrowed from the bathroom.

Technically, I believe, if one is going to install a replacement light fixture then the cable should be rated according to the fixture label and is often 90 degrees C. If accessible, then a junction box with a short length of new cable to the ceiling outlet box might work.

the light fixture will not be replaced (there was never intention to).