CO/ALR - Why not CU/ALR?

[dtontarski]

This is not a need to know, but rather a fill in the blanks question - I figure someone on this forum has the facts -

With CO/ALR rated receptacle outlets -What does the "O" stand for?

Copper is CU - does the "O" stand for copper with a better resistance to oxidation? I know that the "R" stands for revised, but I've always been curious about the "O"...and seeing some solid AL in a home yesterday prompts me to ask. Thanks in advance....man....the things we lose sleep over.

[Jim Katen]

Originally posted by dtontarski

This is not a need to know, but rather a fill in the blanks question - I figure someone on this forum has the facts -

With CO/ALR rated receptacle outlets -What does the "O" stand for?

Copper is CU - does the "O" stand for copper with a better resistance to oxidation? I know that the "R" stands for revised, but I've always been curious about the "O"...and seeing some solid AL in a home yesterday prompts me to ask. Thanks in advance....man....the things we lose sleep over.

Originally, receptacles that were listed for use with copper and aluminum wire were marked cu/al.

There were problems. . .

Subsequently, they needed a marking that was different from the previous one yet still conveyed the fact that the receptacle was listed for both copper and aluminum.

"co" is just an alternate abbreviation for copper and, as you said, "alr" is aluminum-revised.

- Jim Katen, Oregon