2 top branch wires in panel (marked range) appear to be solid aluminum with anti corrosion paste. New construction and has state DOL approval labels. Could these be tinned copper? How can you tell? Thanks and cheers
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See Gerry’s reply
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Aluminum wiring is still permitted and used for certain applications, including residential service entrance wiring and single-purpose higher amperage circuits such as 240V air conditioning or electric range circuits.
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Very odd. I’m guessing that the conductors had no surface markings and you could not see the cable jacket? It’s not tinned copper. The stripe on the red is typical of SE cable but I can’t find anyone that makes what is shown in the photo. Could this be a cable from another country?
I’ve run into this exact same wiring in new construction supplying the exterior A/C Unit. The AHJ told me this was allowed since it was a single source distribution supplying only the A/C Unit. ??? I called the builder (whom I used to work for) and chatted with them about it, since it’s something that will raise eyebrows in the Home Inspector community—and installing 10 Gauge Copper will only add $5 or $10 and remove any questions. Basically, the builder simply hires electricians to wire the homes and meet local codes, but doesn’t specify every component. I think they asked this electrician to change this practice, but I don’t know for sure. My guess is, this practice may fly with some AHJ’s and not fly with others.
I put the following informational comment in the report:
Modern Single-Strand Aluminum Conductors Observed
With the current high price of copper, large-gauge solid (single strand) aluminum branch conductors with simple (direct breaker-to-appliance) wiring are becoming accepted in some parts of the county. For example, using a 8-gauge aluminum cable to wire a dedicated 30-amp circuit to an electrical water heater. The fire hazards with aluminum wiring originating in the 1970’s are (hopefully) a thing of the past. The newer aluminum alloys are much better, plus modern breakers, connectors, and receptacles are available that are designed to accept either copper or aluminum wiring. Thus, this exception is currently deemed to be safe by the authorities (building inspectors) that are allowing it recently for new and remodel installations.
Brian just curious is your example referring to NM cable?
Of course. I think you are going to call me out - the example should probably been 8-gauge aluminum would be needed for a 30-amp circuit. I changed that.
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