Single Strand Aluminum Wiring
Single strand aluminum wiring in the lower 120 volt branch circuits should always be reported with a recommendation for further evaluation and repairs. This system was installed from the mid-1960s through the mid-1970s. Deterioration in the wire connections can cause increased resistance to the flow of electric current, resulting in damage that is cumulative in effect. That increased resistance causes overheating, sometimes at hazardous levels, when current is flowing in the circuit. The concerns do not apply to large gauge 240 volt circuits such as SECs, water heaters, dryers, and stoves.
The Consumer Product Safety Commission (CPSC) strongly recommends remediation of single strand aluminum wiring wherever present. They only approve of 3 repair methods, which are outlined next. The CPSC Repair Bulletin can be found at https://www.cpsc.gov/s3fs-public/516.pdf .
Complete removal of all single strand aluminum wiring and replacement with copper wiring is an obvious solution, and is one of the 3 choices approved by the CPSC. However, this is very expensive and disruptive. It is not considered necessary in most cases.
The COPALUM system involves using a special tool and connectors to permanently “cold weld” a short copper pigtail to the aluminum wire termination. The pigtail is then used to make the final connection. This must be done at ALL aluminum wire terminations and connections, including junction boxes, switches, receptacles, and fixtures. Only electricians who are trained by the manufacturer to use the tool properly are authorized to install COPALUM connectors.
The AlumiConnn® connector system is also approved for pigtail remediations. As with the COPALUM system, all connections and terminations must be repaired. However, no certification is required for the AlumiConn® connector. The repair should be conducted by a qualified electrician because careful, professional workmanship and thoroughness are required to make the connector repair safe and permanent.
Note that other methods are NOT approved as reliable or permanently safe. This includes CU/AL and CO/ALR devices, e.g. switches and receptacles. Twist-on pigtails, including the Ideal #65 Purple Twister, are not approved.
Failed Ideal #65 Purple Twister
There is single strand aluminum wiring present on 120V circuits. This wiring has an established history of safety problems, including loose connections, arcing, overheating, and fires. Hire an electrician for an evaluation and to make repairs as needed. For further information on aluminum wiring contact the U.S. Consumer Product Safety Commission at: https://www.cpsc.gov/s3fs-public/516.pdf .
Knob and Tube Wiring
Knob and Tube is an early form of standardized wiring, and was installed through to the end of the 1930s. Instead of the single cable with multiple conductors that we use today, it ran separate hot and neutral wires. These copper wires used rubber insulation and a cloth sheathing. They were installed on the framing with stand-off ceramic “knobs”, and passed through the framing inside of ceramic “tubes.” As there are only 2 wires the system cannot be grounded. We always report knob and tube with a recommendation for a further evaluation.
Knob and tube installations are generally grandfathered, and if in good condition it is not, in and of itself, unsafe. The problem is that it’s rarely in really good condition. The rubber insulation can become brittle, and break off when moved by renovations, household activity, or animals. Rodents can damage the wiring. Additionally, new circuits are frequently spliced on in an unsafe manner. In the late 1980s, the NEC banned covering knob and tube with insulation because the wires are supposed to be “air cooled.” While a few western states overrode that prohibition, it still stands everywhere else. Inspect its physical condition carefully, and don’t take a statement about “all old wiring updated” as 100% accurate.
There is knob and tube wiring present. This older system cannot be grounded, and often has brittle or damaged insulation. The wiring should be evaluated for condition and safety concerns. Hire an electrician for an evaluation and to make repairs as needed.
There is knob and tube wiring present which is covered with insulation. This is not permitted due to the potential for heat buildup. The wiring should be evaluated for condition and safety concerns. Hire an electrician for an evaluation and to make repairs as needed.
Cloth Sheathed Wiring
Cloth sheathed cable is an early form of “NM” or non-metallic cable. Unlike modern, so-called “Romex” NM wiring, the outer casing is a cloth braid. It was installed primarily from the 1930s through the 1960s. It is almost always a 2-wire system and cannot be grounded. It is rubber insulated and shares some of the same vulnerability to physical damage as knob and tube.
While cloth sheathed wiring does not warrant the same level of concern as knob and tube, it should always be inspected carefully where visible. Damage or signs of overheating must be reported, and when in doubt recommend a further evaluation.
There is cloth sheathed wiring present. Cloth wrapped wiring is one of the early forms of branch circuit wiring methods. This is a potential safety hazard if the insulation degrades or breaks, leaving areas of the wiring exposed. Hire an electrician for an evaluation and to make repairs as needed.
The fireplace’s direct vent terminates in a readily-accessible location. This is a safety hazard, especially for small children. Install an after-market protective vent cover.
