Solid aluminum or tinned copper?

[Erby]

Wow, I'm surprised that AHIT didn't teach you about that, Julie. You might want to give them some feedback about it.

[Jim Katen]

Dang! I wish I'd have known about tinned copper before today! I know I've written up two homes with tinned copper as "aluminum". Well, a mistake is valuable if you learn from it.

Making mistakes is the second-best way to learn.

(The first-best way is to learn from the mistakes of others while you're laughing at them.)

[John Dirks Jr]

If you scratch the tinned copper wire with the end of a flat head screw driver you can usually see the copper underneath. If it's aluminum wire, it will be softer and gouge easier without revealing copper color underneath.

Make absolutely sure you are not touching any metal part of the screwdriver shank. Keep your hand only on the insulated non-metal handle of the screwdriver. Otherwise, you could get a shock.

If poking around in the panel makes you feel uncomfortable, don't do it.