Would it be acceptable safe practice to join a Cu branch circuit to an Al branch at a receptacle, if you used a different receptacle screw for each wire??
John Kogel
www.allsafehome.ca
Is this something you have come across during an inspection or something you are thinking of doing this. Alum has to have special devise’s dedicated for the use with Alum wire some areas allow the pig-tailing of Cop to Alum at the outlet using approved wire nuts. If the outlet is rated for Alum wire then you could apply the copper to the outlet directly to the screw
I don’t remove cover plates so no, this is not something I’ve found but want an answer ready for Mr. Handy. Thanks for that.
When deciding to repair or replace any electrical installation, a qualified professional should be consulted.
I’d advise removing a random number of coverplates to examine how or what connections or alterations have been made and the type of receptacles present just to improve your reporting and discussion with clients. jmo Others will advise the opposite leaning on the SOP, oh well…
Upgrading aluminum-wired homes
There are several “upgrades” that are commonly done to homes with pre-1974 aluminum branch circuit wiring:
- Ensuring that all devices are rated for use with aluminum wire. Many are not, since they do not meet the CO/ALR specification.
- “Pigtailing”, which involves splicing a short length of copper to the original aluminum wire for use with devices not CO/ALR rated.
- COPALUM, a sophisticated crimping system that creates a cold weld between copper and aluminum wire, and is regarded to be a permanent, maintenance-free repair. These connections are sometimes too large to be installed in existing enclosures. Surface enclosures or larger enclosures may be installed to remedy this problem.
- Alumiconn http://kinginnovation.com/products/alumiconn.html
- Completely rewiring the house with copper instead.
Thanks Barry. Isn’t crimping and using Copalum connectors the same thing?
As far as removing a cover or two, I think we saw a case recently where pulling the receptacle out for inspection resulted in a dead short and a bit of a fire. :)Oops.
The other factor is a couple of random, easy access outlets are inspected, they are good, now we might make a false assumption that all other outlets are similar. You still need to call for an inspection of the rest of the outlets, because you can never be sure. (I just found 2 outlets in my 30yr old living room that were never grounded, no grounding lead was ever attached.)
Useally no it is not most case due the standard crimping barrel useally is either brass or steel once a while copper too also.
The copalum connectors are diffrent beast they are stragiht alum connector and used specal criming device to used this item.
There are few other approved items that can be used as well.
Merci,Marc
hth you understand my methodology beside it’s required in Texas that the inspector remove a random number of coverplates…ba-da-bing-ba-da-boom! Never have gotten an answer as to how many is in a "random’
Merci to you also, Marc
Fair enough. 
So is it OK to use the receptacle screws to join a new Cu branch to an existing Al branch?
You are joking right?
Actually, if you’re using an AL/CU rated receptacle, you can terminate AL conductors on one set of screws and CU conductors on another set of screws, and you’re fine. That’s a perfectly acceptable method for a conductor material change, such as a copper extension from an aluminum wired circuit. I can’t say that I’ve ever had to do that, but it’s 100% legal and safe. I will add, however, that’s it’s not a good idea to add any additional load to an existing aluminum wired circuit if you can do it some other way.
Thanks Marc. And good point about keeping the load reasonable.
And thanks Terry, I just had to hear it agin.:)
Look for CO/ALR rules in the NEC for devices and receptacles.