Safe to use old copper wire?

[g-rat]

I want to run power from my service meter to a 100A subpanel in a metal shed 125 ft. away.
My grandfather has a roll of wire left over from a job. It has been stored outside for 12 years. There is noticeable oxidation, but the wire is good condition. No breaks or missing insulation.
I'd like to use this since it's free and the price of new wire will cost over $500.
Is this wire safe to use?
Is there any risk of fire due to oxidation?

 

[Greeny]

Following along to see what the experts say, but you don't mention how the run will be made. Buried conduit? I'd also be interested to see what the wires look like a foot or so back from the current exposed ends.

 

[Stuart in MN]

Cut the insulation back to see if you can get to clean copper, the corrosion can extend inside the insulation quite a ways - you want to have clean metal at the connections. Of course, you need to make sure the wire gauge is sufficient for your application, and that the cable is rated for your use (whether it's buried, in conduit, or overhead.)

 

[kd3pc]

I would cut it back a foot or so and make sure you have the best ends you can get. And use a "noalox" or similar product when you make the connections.

bests....let's see what others say?

 

[gungatim]

last time I tried to use wire like that, I had to keep cutting back a foot until I realized the corrosion was all through the entire cable.

if it's clean further back, fine, if not, sell it for scrap.

 

[g-rat]

Thanks for the replies.
The run will be buried conduit. I will cut off each of the ends and clean the connection points.
Say the entire length of wire is corroded. Are there any safety issues with using it?

 

[tyme2par4]

Thanks for the replies.
The run will be buried conduit. I will cut off each of the ends and clean the connection points.
Say the entire length of wire is corroded. Are there any safety issues with using it?

Yes. Corroded wire will have much higher resistance, and will heat up under load. If you cut it back a foot or two, and it's not nice clean copper, it should go to the scrap bin.

 

[rlitman]

last time I tried to use wire like that, I had to keep cutting back a foot until I realized the corrosion was all through the entire cable.

if it's clean further back, fine, if not, sell it for scrap.

Exactly. Oftentimes, the space between the strands wicks water up into the wires.

 

[pattenp]

Even if not corroded you need to read the markings on the jacket to see if it's allowed underground.

 

[Norcal]

NM cable is not permitted underground or outdoors also to be used at all needs to be marked on the sheathing as "NM-B" as it requires a 90 degree rating & NM is only 60 degree rated, in addition to being at least 35 years old.

 

[g-rat]

Good news, the wire is clean 1' back.

There are no markings on the exterior wire, but talking to my grandfather he said this is direct burial wire purchased by a gas company when installing a compressor station. The company bought extra wire and was going to scrap any left over. Some of the guys on the job site cut lengths out with the intent to run power to barns/sheds.

I think I will go ahead and use it, thanks for all the advice.

 

[American Locomotive]

That does not look like 100a wire. That looks like 8 gauge, which wouldn't even be good for 50 amps.

 

[wyliesdiesels]

I want to run power from my service meter to a 100A subpanel in a metal shed 125 ft. away.
My grandfather has a roll of wire left over from a job. It has been stored outside for 12 years. There is noticeable oxidation, but the wire is good condition. No breaks or missing insulation.
I'd like to use this since it's free and the price of new wire will cost over $500.
Is this wire safe to use?
Is there any risk of fire due to oxidation?

I wouldnt use it. Water can wick up inside the insulation.

I would cut it back a foot or so and make sure you have the best ends you can get. And use a "noalox" or similar product when you make the connections.

bests....let's see what others say?

Noalox is mainly for aluminum and doesnt really have a benefit for copper, especially corroded copper.

Furthermore, its only required if the manu calls for it which many do not.

NM cable is not permitted underground or outdoors also to be used at all needs to be marked on the sheathing as "NM-B" as it requires a 90 degree rating & NM is only 60 degree rated, in addition to being at least 35 years old.

That doesnt even look like NM to me as there are 4 insulated conductors and one bare ground. The jacket also looks like hard extruded insulation like whats on XLPE. NM-b has a soft jacket.

Did southwire ever make a 5 wire NM?

Good news, the wire is clean 1' back.

There are no markings on the exterior wire, but talking to my grandfather he said this is direct burial wire purchased by a gas company when installing a compressor station. The company bought extra wire and was going to scrap any left over. Some of the guys on the job site cut lengths out with the intent to run power to barns/sheds.

I think I will go ahead and use it, thanks for all the advice.

If there are no markings, I would not use it. NEC requires wire to be marked. You have no clue what kind of wire that is.

I dont even recognize the type of wire. Its not NM as the outer jacket is hard and NM never came in 5-wire version AFAIK.

As said above, gauge looks to be too small.

Instead of cheaping out, why dont you buy the correct wire?

Tell us how long the run is. I bet you could use AL maybe even MHF and spend way less than your estimated $500.

 

[Norcal]

I went by the original photo which looked like NM this is why good photos are a must.

 

[pattenp]

Look hard at the jacket, the markings maybe embossed. Wipe it with a wet rag to see if markings show up.

 

[topcok88]

I am going to guess he will use it whether or not anyone tells him otherwise. Obviously using old, corroded, outdated wire is not optimal he already sounded sold on the idea when he came in here to save a few bucks.

Now based on the sheath and cables marked with a numeral, it appears to be VNTC (tray cable) from an industrial environment. And I do know of industrial areas where they may push a wire like that due to it laying exposed in a cable tray, but you wouldn't catch me doing it on my personal property. 100amps through that? Wow!

 

[g-rat]

That does not look like 100a wire. That looks like 8 gauge, which wouldn't even be good for 50 amps.

From what I researched 3-3-5 is recommended for 100A. This measures just under a quarter inch in diameter. 3 awg is 0.2294"

I am going to guess he will use it whether or not anyone tells him otherwise. Obviously using old, corroded, outdated wire is not optimal he already sounded sold on the idea when he came in here to save a few bucks.

Now based on the sheath and cables marked with a numeral, it appears to be VNTC (tray cable) from an industrial environment. And I do know of industrial areas where they may push a wire like that due to it laying exposed in a cable tray, but you wouldn't catch me doing it on my personal property. 100amps through that? Wow!

Opposite actually. I was very reluctant to use this at 1st, which is why I priced new wire & asked for help here. I was told check for oxidation 2' back. If it's clean then use it.

There is definitely not any markings on the outside of the cable. I just double checked. This was left over wire purchased in an industrial environment and buried to a compressor station. What is VNTC and why wouldn't you use it?

100A subpanel which will have 15A light circuits, 20A receptical circuits, and a 30 A reciptical dedicated to a window unit air conditioner.

 

[topcok88]

The XLPE (that Wyliesdiesels spoke of) and the VNTC (I spoke of) are just tray cable commonly used in industrial environments. They are commonly used in open air in tray raceways, can be hung overhead, can be used direct burial, can be used in conduit, and can be found in many conductor sizes with a wide variation of conductor counts. I firmly believe TC is superior to NM-B and the ratings are often similar or superior to NM-B. But I doubt it would be acceptable in any fashion to use residential (I'm not a electrician - I only work in the nuclear power generation industry). I would have no issues using VNTC honestly, but I wouldn't breaker that at 100 amps. And based on what you are powering in that shed you could easily get away with 60 amps. Just food for thought.

 

[alfredeneuman]

It's called Power and Control Tray Cable and is available in all sorts of wire configurations.
Instead of color coding the conductors, the makers often print the number on them in the larger sizes.
It's covered in Article 336 of the NEC
Only suitable underground when listed for the use (I've used quite a bit of it and never had any listed for underground).
Even the #14, #12, and #10 are stranded and the overall jacket is nowhere near as rugged as that of NM.

 

[topcok88]

Alfredeneuman - that is interesting as I have found very little VNTC that isn't rated for direct burial or underground use. And although stiffer and tougher to pull, the VNTC sheathing is typically more durable than NM-B because it must withstand UV exposure, austere industrial environments, and such. I have some in the basement and was thinking of taking photos to show the difference. VNTC is nothing more than numerically labeled THHN/THWN with a heavy duty outer cover.... It really is that durable and anyone that has seen miles of it in commercial power plants will tell you, it is miles ahead NM-B.

 

[MikeRock]

If you measured the diameter of a strand with a micrometer, and reported the number of strands in a conductor, the equivalent AWG of the conductor could be deduced. Still reasons not to use it: other unknown characteristics and lack of markings not to code.

 

[wyliesdiesels]

From what I researched 3-3-5 is recommended for 100A. This measures just under a quarter inch in diameter. 3 awg is 0.2294"



Opposite actually. I was very reluctant to use this at 1st, which is why I priced new wire & asked for help here. I was told check for oxidation 2' back. If it's clean then use it.

There is definitely not any markings on the outside of the cable. I just double checked. This was left over wire purchased in an industrial environment and buried to a compressor station. What is VNTC and why wouldn't you use it?

100A subpanel which will have 15A light circuits, 20A receptical circuits, and a 30 A reciptical dedicated to a window unit air conditioner.

So how long is the wire run?

 

[mm08822]

Here is a link to VNTC mfr specs:

http://www.awcwire.com/producttoc.aspx?id=vntc-control-cable-type-tc-er

If you have access to a megger, I would test it out. Short of that, an ohmmeter then power it up with a load using all conductors. Use a large heater.

As suggested before, measure the individual strands, etc to determine gauge for certain so you know proper ocp.

This is a great case for conduit all the way b/c if it fails.............It has to be, as I didn't see any direct burial ratings in mfr info.

 

[James-W]

If it were me I would just buy the correct wire for the job and be done with it. I am all for saving a buck when I can, but sometimes trying to save a buck is not such a good idea. Sometimes it is best to bite the bullet, spend the money and do the job so that you know full well it is done right.

 

[g-rat]

Thanks for all the feedback. Looking at the specs for VNTC it has an insulation rating of 90°C which makes me feel better about using the wire.

I was originally thinking that since the subpanel is 100A I had to have a 100A breaker at the service pole. After talking to an electrician I work with he informed me that's way too high. He suggested a 40-60A breaker instead. I will replace the 100A breaker with a 50A amp breaker, this should eliminate any risk of overheating.

Before burying it I'll hook it up on top of the ground and test it running as heavy of a load as possible, as suggested by MM08822. I have access to a thermal imaging camera that I can use to check temperatures as well.

 

[mm08822]

Here is a link to VNTC mfr specs:

http://www.awcwire.com/producttoc.aspx?id=vntc-control-cable-type-tc-er

If you have access to a megger, I would test it out. Short of that, an ohmmeter then power it up with a load using all conductors. Use a large heater.

As suggested before, measure the individual strands, etc to determine gauge for certain so you know proper ocp.

This is a great case for conduit all the way b/c if it fails.............It has to be, as I didn't see any direct burial ratings in mfr info.

Actually, upon second look on mfr website, the 600v rated tc is direct burial rated, but i would still run conduit entire way.