Aluminum lateral service conductor ?

Hi guys - Inspected a home built in 1973 in New York yesterday with a lateral service. At the main panel I used my gauge to determine size of conductor and determined it to be 150amp copper. However, the exposed wiring was silver. Was aluminum used as lateral service conductor? Or might it be tin coated? The gauge (plastic thingy) read copper and the aluminum slot was a tad too big. Thanks!
P.S. You can probably tell I’m a “newbie”

I’ve never seen tin coated copper cables at the SE. They are normally all aluminum or all copper.

If you seen Aluminum, I believe you had aluminum cable.

Thanks David - I guess I can throw the gauge away now, it bothers me that the gauge reads 150amp copper exactly and 150amp aluminum was too loose.

Don’t throw the gauge away.

Just mark it up…appropriately.

I bet it was tinned copper.
For one thing, I have NEVER seen AL service conductors used on LI. Of course there probably is some somewhere, it’s just NO ONE “typically” uses it.

Could you see the ends of the conductor strands where it was cut? That is the tell tale answer.

I had no idea they actually manufacture tinned copper cables for the SE. I’ve never seen it, here.

Oh, I don’t think I’ve ever seen it new. I’m talking an old installation. I think '73 is borderline.

They sure did. The jacket was normally either braided or really super thick neoprene type rubber.

He said this was a lateral, so I’m assuming he means underground? There was certainly tinned copper URD, and there was even a concentric neutral URD used from approx '62-'67 that had insulated aluminium hots and a bare concentrically wound copper neutral. That’ll throw you for a loop the first time you see it.

There are also “compact” aluminum conductors (the strands are not round) that may trick your gauge. I am not sure if this ever made it to USE type conductors tho.
Aluminum service laterals are pretty normal in new construction these days. It is usually a triuplex, similar to or the same as overhead drops. I have watched the FPL contractors install them but I wasn’t the AHJ so I didn’t really “inspect” it. I probably should have picked up a scrap and looked at it to see what it was labelled

That’s new to me. I’ve never run into an aluminum cladded copper SE cable and probably never will.

Here’s the reason why copper is tinned.](

So that explains why SE cables aren’t tinned. They simply do not need the coating.

You don’t think “corrosion resistance” as an asset?

In real life, I bet he was looking at aluminum (1973)