Between approximately 1965 and 1973, single-strand (solid) aluminum wiring was sometimes substituted for copper branch-circuit wiring in residential electrical systems due to the sudden escalating price of copper.
In brief, these materials were banned in the late 1970’s due to problematic nationwide history, including arcing, shorts, and fires. Installer errors, device incompatibilities, and material behavior all contribute to the problems. Stranded aluminum is still used for larger circuits, such as for ranges and service entrance cable. The problem is often compounded over the years by electricians who attempt to “mitigate the risk” but who in fact increase the risk due to improperly executed updates or materials.
Generally, a home inspector will recommend removing the solid core aluminum branch circuits entirely, and replacing them with copper branch circuits. A new distribution panel, switches, and electrical outlets are also recommended. This will require permitting. (Single-family homes)
At a bare minimum, have a licensed electrician (who is proficient in this material and its related concerns) evaluate all areas- including all distribution panel connections, all junction boxes (including the attic), all fixture locations including lights, switches and outlets, making any necessary corrections or updates (such as CO/ALR designated devices and proper copalum aluminum type wire nuts) to better guarantee occupant safety. Nicked solid core aluminum conductors must be reworked. Additionally, I recommend annual spot checks for the home’s electrical system if the aluminum is not deleted and replaced. DO NOT allow any unlicensed, uninsured, or unsupervised individuals to touch the system.
Note: Pig-tailing aluminum to copper (a common “update” used by some local electricians) is highly discouraged. This can overcrowd boxes, and, incorrect wire nuts are almost always used which increases the risk of problems. Consult a qualified, licensed and insured electrician only.
Any and all “updates” should be clearly documented in writing, on a licensed and insured electrician’s invoice; otherwise they may be unreliable, inferior, and potentially unsafe. Related verbal conveyances of work performed have no value whatsoever and should be considered worthless until verified by a licensed electrician.