How to determine wiring type in house

My house was built in '72 so from what I've read there is a strong possibility that it was originally done with aluminum wiring. However from the 5 year old inspection list I see "100A aluminum main; copper fabric/romex; breakers" listed as the electrical description. Would that mean the main box is wired with aluminum while the rest of the house has copper wiring? I've replaced some outlets and am trying to figure out if I need to go back and replace them with the specialty aluminum ones?

The wires in the outlets look copper but I've also read that its easy to mistake the copper coated aluminum ones for copper.

I have suspicions that the house was rewired at some point though because when replacing drywall in the bathroom there was a nonlive set of wires hanging next to the outlet.

 

Welcome to the forums! Entrance cables are often aluminum, which is pretty much standard. No problem there. Would it be possible for you to pull a receptacle from the wall (power off) and let us see what type wiring you have? http://www.doityourself.com/forum/el...your-post.html

 

A lot of homes were wired with aluminum wire during the period in which your home was built, but many were still wired with copper wire too. That non-live set of wires you found, were they aluminum? Aluminum wire looks just like it sounds, like aluminum. Copper clad aluminum wire will look like copper, but the ends will clearly be aluminum colored. Both aluminum and copper clad aluminum NM cables are usually clearly labelled on the outside of the cable. If you have access to these cables, perhaps in your basement, look for "ALUMINUM" in all caps. Also, there were two major manufacturers whose names I remember frequently seeing, Alcoa and Kaiser. There were other manufacturers too, like EtcoFlex and General Cable, but those two aluminum company names are the two I remember as being the most common. If you can, do as Chandler has suggested and post some pictures with close-ups and several angles so we can see the wire.

 

Finally managed to get a few pictures. I tried looking for writing on the wire coverings but haven't been able to find any. We don't have a basement so I'd have to dig through the insulation in our sealed off attic to see if i could find the writing on those...which i'm hesitant to do.


This looks like copper on the outside to me but the silver in the middle makes me think its aluminum in the center


This one look likes it would be pure copper to me.

 

Rest easy, it's copper....................

 

They are both copper if they came from the same cable. The white wire is just shinier from the way it was cut.