What wire insulation type is this?

[MrJLH]

Had to swap a breaker of what I thought would be an easy job.

Needless to say, what wire insulation type is this?

 

[texie]

That's type OLD...as in very old.

 

[MrJLH]

I don't see "OLD" anywhere listed on the wire.

 

[infinity]

Looks like tin coated copper, RHW insulation.

 

[don_resqcapt19]

I would agree that it is tin coated copper with cloth covered RHW. The tin coating was used to protect the copper from the sulfur in the rubber insulation.

 

[LarryFine]

I was gonna say RHW even before reading the previous responses.


I was.


I was!

 

[Dennis Alwon]

I also agree RHW

 

[PaulMmn]

I'd say it's OLD as in "touch it and it'll break."

 

[Jraef]

Probably more like RH, not RHW if it was indoor wiring. The "R" stands for Rubber impregnated cloth covering, the "H" was for High heat, "W" would have been for Water proof and back in the days when they still used cloth as an insulator, the W would have been an expensive adder so you wouldn't have used it for indoor wiring. This likely dates to the 40s or 50s, early 60s at the latest, before everything changed to plastic or plasticized rubber.

 

[ActionDave]

I would agree that it is tin coated copper with cloth covered RHW. The tin coating was used to protect the copper from the sulfur in the rubber insulation.

I never knew that. Cool.