CU/AL revised?

[JJWalecka]

is CO/ALR the same thing as AL/CU? please explain the difference

I read that [SIZE=-1]If your home has aluminum wiring and you need to replace a switch or wall receptacle, [/SIZE][SIZE=-1]the replacement unit should bear the marking "CO/ALR". This means [/SIZE][SIZE=-1]"Copper Aluminum Revised" to differentiate these units from earlier models which were marked AL/CU. [/SIZE]

 

[jumper]

A similar thread as a place to start.

http://forums.mikeholt.com/showthread.php?t=106365

 

[JFletcher]

I pigtail to Cu using Alumiconns and regular devices. Other methods may work, but I'd rather stock one thing and use standard receps/switches than go buy overpriced specialty items.

 

[Jraef]

is CO/ALR the same thing as AL/CU? please explain the difference

I read that [SIZE=-1]If your home has aluminum wiring and you need to replace a switch or wall receptacle, [/SIZE][SIZE=-1]the replacement unit should bear the marking "CO/ALR". This means [/SIZE][SIZE=-1]"Copper Aluminum Revised" to differentiate these units from earlier models which were marked AL/CU. [/SIZE]

As I understood it when it changed, the old CU/AL was only based on the dissimilar metals issue and could be met by simply coating the connections with tin plating. The problem is, that's not the only issue. There is also a severe difference in the coefficient of expansion; aluminum changes shape when heated more than copper does. So if the wiring device terminals were designed around copper, then just tin plated to allow for aluminum, eventually the connections failed because of the expansion and contraction of the AL wires. The 'Revised" version incorporated changes to the design of the terminals themselves.

 

[JJWalecka]

As I understood it when it changed, the old CU/AL was only based on the dissimilar metals issue and could be met by simply coating the connections with tin plating. The problem is, that's not the only issue. There is also a severe difference in the coefficient of expansion; aluminum changes shape when heated more than copper does. So if the wiring device terminals were designed around copper, then just tin plated to allow for aluminum, eventually the connections failed because of the expansion and contraction of the AL wires. The 'Revised" version incorporated changes to the design of the terminals themselves.

Thanks