As you can see from my post history, I am blessed with a lovely home with aluminum wiring. I am also taking steps on every project to review and mitigate the risks of aluminum wiring by using proper pigtails or Alumiconn connectors.

The authoritative references on aluminum wiring seem to have been written at least a decade ago. Have the risks from aluminum wiring been mitigated to any extent by high-efficiency fixtures and appliances becoming more common?

My thought process is that an LED fixture will generate the same light with significantly less draw. This reduced draw reduces the heating and expansion of the wiring. The expansion and contraction is what causes the separation in AL and CU/AL joins. That separation then induces the sparking that gets people hurt.

My question is entirely focused on theory rather than application. Even if modern loads actually reduce the risk, it is still imperative to use the correct connectors and strategies with AL wiring. Using proper solutions, such as crimp connectors, AFCI breakers, and proper boxing nearly eliminates the risk which is far better than any theoretical reduction.

  • Lower ampacity will reduce risks. I use aluminum on house feeders because they are usually much larger than the current draw where individual branch circuits are usually loaded to the max. For this same reason I only use copper on motor loads because I have seen two many wire failures with aluminum I believe because the in rush current is much higher even though it is for a short time. Using proper connectors like alumicon and reducing the ampacity can only help make it safer. – Ed Beal Sep 25 '17 at 15:28

Have you considered having a witch doctor chase the wolfram demons away? Seriously, that would be the same kind of improvised guesswork "spray and pray" that you're talking about here. Focus on what is known to work.

AFCI breakers

What are you concerned about? Fires. Why? Because temperature changes, plastic deformation, dissimilar metals corrosion, and oxidation are causing contact surface/pressure to be lost. How would that start a fire? Arcing.

AFCI breakers are uniquely good at catching that. They are stupid easy to install.

If you have a main panel like a Pushmatic that does not support them, then install a subpanel and route your wiring to it. Possibly one on each side of the main panel so you don't have to extend wires very much.

And when an AFCI breaker trips, treat it seriously.

Metal boxes

Of course a contact can just overheat. But that is vanishingly unlikely to be a problem in a metal box, becuase the heat has to reach the metal box before it can reach the wood, and metal has such very good thermal conductivity that it will make the entire box warm, rather than a small part of the box hot enough to ignite anything. And of course if the box is grounded, the arcing will cause an AFCI trip.

I would also recommend metal box covers, same reason, if they're grounded.

But in the aluminum wiring age, metal boxes were pretty common. I would change out any plastic ones.

Between AFCI and metal boxes, I wouldn't even rush to do the Alumiconns and all that.

  • As I stated, "My question is entirely focused on theory rather than application. Even if this does reduce the risk, it is still imperative to use the correct connectors and strategies with AL wiring. ". This answers outlines AFCI breakers and metal boxes as the correct solution, but it doesn't address the question I am actually asking. – Freiheit Sep 25 '17 at 17:15
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    Because those things moot your question. Ergo your question only has a scope of "if I don't have them" and I'm saying that is a null space, since getting them is a much higher priority. It's not like any of us own a testing lab, so the best we can do is arm-wave extrapolations from theory. Which will tend to be a bit "bull"ish... ... – Harper Sep 25 '17 at 17:52
  • Thats a hard truth to get whacked over the head with, but you are correct. – Freiheit Sep 25 '17 at 18:26

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