[FlyingSparks]

What would cause this copper to have this discolored appearance? (Top wire is the discolored one). The wire is preexisting, and what you see is the copper in the wire -- I stripped off a foot of insulation to see if it was exposure of some sort.

For reference I put a piece of #12 THHN next to it.

 

[Swordsman]

Copper wire goes through an annealing process as it's drawn during manufacturing. This may have gotten a little warmer than usual. I've seen it many times over the years. It will have no impact on it's use.

 

[Tapeman]

The only time it matters is when you are selling it for scrap. They pay the most for "shiny" copper.

 

[Meadow]

Maybe its gold? :whistling2::laughing::jester:

 

[Bad Electrician]

http://www.eng-tips.com/viewthread.cfm?qid=135673

http://www.wirenet.org/wai-forums/8-nonferrous/1292-how-to-predict-copper-wire-discoloration-defect

http://www.fe-cable.com/English/newsInfo.asp?ID=1398

 

[Meadow]

http://www.eng-tips.com/viewthread.cfm?qid=135673

http://www.wirenet.org/wai-forums/8-nonferrous/1292-how-to-predict-copper-wire-discoloration-defect

http://www.fe-cable.com/English/newsInfo.asp?ID=1398

You rock! :thumbup::thumbup:

 

[dmxtothemax]

Heat is what has caused that wire to dis-color !
Was the connecttion good ?
Could it have been loose or a dirty connecttion ?

 

[wildleg]

heat - that color ? not so sure about that.

that looks to me like more of a manufacturing glitch.

then again, what the hell do I know.

 

[FlyingSparks]

Thanks for the answers so far. It was just something interesting I noticed today. That discolored copper wire was connected to a piece of #12 stranded THHN/AWM that was connected to a 20a OCPD. If I had to rate the quality of the connection I would say it was between starting a fire and causing some sort of nuisance.

 

[wildleg]

Thanks for the answers so far. It was just something interesting I noticed today. That discolored copper wire was connected to a piece of #12 stranded THHN/AWM that was connected to a 20a OCPD. If I had to rate the quality of the connection I would say it was between starting a fire and causing some sort of nuisance.

hmm, I guess I was totally wrong. :thumbsup:

 

[FlyingSparks]

hmm, I guess I was totally wrong. :thumbsup:

I wouldn't be so sure about that. I'm thinking a manufacturer defect is very possible.

 

[magitrician]

Heat, age, manufacturer, all sound very resonable.

Sent from my SM-G900V using electriciantalk.com mobile app

 

[RIVETER]

What would cause this copper to have this discolored appearance? (Top wire is the discolored one). The wire is preexisting, and what you see is the copper in the wire -- I stripped off a foot of insulation to see if it was exposure of some sort.

For reference I put a piece of #12 THHN next to it.

I've seen it too. It is also harder to form. I think that it is recycled and other metals get in the mix. The metallurgists at the plant make sure that it is "good enough" to be used in building wire.

 

[Joefixit2]

I dunno but I am getting tired of home inspectors calling out heat damage on tarnished copper busses.

 

[Wpgshocker]

I've seen it too. It is also harder to form. I think that it is recycled and other metals get in the mix. The metallurgists at the plant make sure that it is "good enough" to be used in building wire.

Recycled copper added to the the mix. Has to be.
I was just using some 18/4 and one of the conductors was slightly brassy. Stood out against the other 3.
My guess is cheap a$$ cable.

 

[Swordsman]

If you do a side by side comparision of the discolored wire and what we normally get you'll find the discolored wire is harder to bend. That's because it's what we call hard drawn copper wire. The annealing causes this. It doesn't hurt the copper or cause it to be any less conductive. It's just harder and a different color. Were they to recycle it the hardness would be removed when smelted and the color would return to that nice shiny copper color. The only downside is that the copper crystalline lattice is less random leading to faster metal fatigue if one were to bend it excessively.