Here’s a close-up of the fusebox with the 40-amp fuses. I don’t see anything there that looks like aluminum wire. It would surprise me to find aluminum wiring anywhere in this house. It was built in 1951, and I don’t think any of the wiring was ever changed.
Looks like there is an aluminum ground wire coming in from the BX on the bottom. I think this was pretty common.
I thought the white wire from the BX was aluminum, but I was fooled by the rivet just below where it’s connected. In the wider photo the rivet looked like aluminum wire.
I agree. Looks under gauge for the amperage. Mixed too?
IANAE, but I believe the risk depends on the alloy. Aluminum alloy AA-1350 was discontinued for homes in the 1970s because it caused fires. Today, the AA-8000 series of aluminum alloys is used, and this alloy closely mimics the mechanical properties of copper (creep, elongation, CTE, etc.). So for the OP, if there is any aluminum wiring in the house, then I believe I believe the risk would depend if the alloy is AA-1350 or AA-8000 series. Not sure how this determination would be made, though.
IANAE either, my understanding is that most of the risk came from solid 12AWG that was used on 15A circuits or 10AWG on 20A circuits (Al needs to be upsized from Cu for the same current capacity) as the wire was not as ductile as copper and more than about 4 bends in handling during installation could cause a weak spot. The new alloy addresses the issues, but you still need a dual rated device to connect it and code never went back to allow it for sub 30A circuits.
Agree, and you’ll find that almost all receptacles, fixtures, etc. are stamped with “CU/AL” or “AL/CU” to signify it can be used with copper or aluminum wiring. However - and this is what a lot of people don’t know - the “AL” means it can only be used with the AA-8000 series aluminum wire, not the AA-1350 aluminum wire.
All of which aluminum discussion would be irrelevant to a house that was built in 1951 and not updated since. Although that BX and that aux fuse box shown in the closeup certainly look newer than 1951 practice.