Aluminum Wire Guage

Could anybody tell me what guage wire they think this stranded aluminum is? No legend at panel but looks like going to a transformer. The breaker itself is 15 amp bryant also kind of loose. Panel has a light buzz to it as well but I believe that is common on 200 amp service. Wire looks wrong to me but I usually see copper for 15 and 20 amp branch wiring.



It is probably the supply wire to that 24V AC doorbell or thermostat transformer. These units come with stranded aluminum hot and neutral leads embedded, e.g. https://www.homedepot.com/p/Newhouse-Hardware-Wired-16-Volt-AC-10-Volt-A-Doorbell-Transformer-for-Wired-Door-Chimes-UL-Class-2-Certified-16TR/206973663. They draw next to nothing. Personally I don’t report that when the usage is right there. Can you confirm that it is the supply to the transformer at the right?

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Can’t answer what size, but it’s a non-issue. It powers an electrical component, not branch wiring/circuit. It appears to be properly located and wired on it’s own breaker. The breaker will usually be slightly loose without the cover in place.
Good question, but move on.

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Not in my experience. If a panel of any ampacity is “buzzing”, it is most likely a noise from a breaker or that transformer bolted to the side.

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Yes I could. And thank you.

Is it a defect if breaker?

Thanks Jeffrey!

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The conductor in question is not aluminum. It is tinned copper.

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I agree with Jim, it is more likely tinned copper than aluminum. Since those transformer leads are typically #16 AWG the breaker should have a pigtail and a wirenut because the CB terminal is too large and likely not listed for that conductor.

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How do you recongize tinned copper?

Best way is to try and view a wire end where it has been cut.

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