Question

[tkirk911]

I have been in the trade for over 20 years and it appears my mind is fading. In table 9 what is uncoated wire? I know it can't be the insulation.

Brain Dead needs help.

 

[electricman2]

Uncoated = Untinned.

 

[LarryFine]

If I'm not mistaken, copper wire from the old days, like knob-and-tube and early BX, was nickel-plated, and we were supposed to scrape of the gray coating for terminations and splices.

Old Klein electricians' pocketknives had a blade with a scraper edge for this.

 

[coulter]

... we were supposed to scrape of the gray coating for terminations and splices. ...

Nickel plating - wow! Expensive, pretty corrosion resistant. Why would it need to be scrapped?

carl

 

[LarryFine]

Nickel plating - wow! Expensive, pretty corrosion resistant. Why would it need to be scrapped?

No, scraped, not scrapped; that's what we do with it now. :smile:

Scraping was for exposing the copper, to reduce contact resistance.

 

[coulter]

...Scraping was for exposing the copper, to reduce contact resistance.

Humm ... Still somewhat surprised. Low contact resistance is generally the result of a gas-tight, corrosion free, high pressure connection. Still not understanding why the nickel would need to be scrap(p)ed off.

 

[steve66]

I think coated wire has a varnish applied before the insulation. Not sure why, and not sure if I'm right.

Steve