Aluminum branch wiring noted in sub panel

Between approximately 1965 and 1973, single-strand aluminum wiring was sometimes substituted for copper branch-circuit wiring in residential electrical systems due to the sudden escalating price of copper. After a decade of use by homeowners and electricians, inherent weaknesses were discovered in the metal that lead to its disuse as a branch wiring material. Although properly maintained aluminum wiring is acceptable, aluminum will generally become defective faster than copper due to certain qualities inherent in the metal. Neglected connections in outlets, switches and light fixtures containing aluminum wiring become increasingly dangerous over time. Poor connections cause wiring to overheat, creating a potential fire hazard.

Aluminum-Wiring-

 

I suggest that, if you’re considering purchasing a home with aluminum wiring or have discovered aluminum wiring after moving in, that you hire a licensed electrician to inspect the wiring for the following:

 

1) Fixtures (eg: outlets and switches) directly attached to aluminum wiring should be rated for it. The device will be stamped with “Al/Cu” or “CO/ALR”. The latter supersedes the former, but both are completely safe. These fixtures are somewhat more expensive than the ordinary fixtures.

2) Wires should be properly connected (at least 3/4 way around the screw in a clockwise direction). All connections should be tight. While repeated tightening of the screws can make the problem worse, during the inspection it would pay off to snug up each connection.
{Note that stranded aluminum wiring is still often used for the main service entrance cable at your main panel. It should also be inspected.}

3) The “push-in” terminals are an extreme hazard with an aluminum wires. Any connections using the push-in terminals should be upgraded with the proper screw connections immediately.

4) There should be no signs of overheating: darkened connections, melted insulation, or “baked” fixtures. Any such damage should be repaired by a licensed Electrician and the connection should be upgraded.

5) Connections between aluminum and copper wire need to be handled specially. Current codes require that the connectors used must be specially marked for connecting aluminum to copper. The NEC requires that the wire be connected together using special crimp devices, with an anti-oxidant grease. The tools and materials for the latter are quite expensive – not practical to do it yourself unless you can rent the tool.
{Note that regulations are changing rapidly. Suggest that you discuss any work with an Electrical inspector if you’re going to do more than one or two connections.}

6) Any non-rated receptacles can be connected to aluminum wiring by means of a short copper “pigtail”. See #5 above.

7) Shows reasonable workmanship: neat wiring, properly stripped (not nicked) wire etc.

If, when considering purchasing a home, my inspection of the exposed wiring (in your prospective home) shows no problems, you can consider the wiring safe. If there are signs of electrical problems in many places (which will be noted on your home inspection report), I suggest you consider a complete electrical inspection and possibly upgrading all branch wiring throughout the house. If the wrong receptacles are used, you can replace them with the proper type, or have the Electrician use pigtails. Having this professionally done by a licensed Electrician can run close to $10.00 or more per receptacle/switch plus hourly labor.

For questions about aluminum wiring in your home or to schedule a residential property Inspection, please contact us at: 800.441.0804 or visit http://goldenstatehomeinspections.com

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