What remediation methods and standards were developed for aluminum wiring?

by Nils Deacon, Manager, Inspections and Rating Services

Aluminum wiring is used extensively today and is safe if properly installed. It is used in a variety of applications, most commonly for large supply conduits.

Aluminum remains the industry standard for heavy-duty, large-gauge applications like service entrance cables and main feeder lines, provided the correct antioxidant pastes and lugs are used.

Service entrance cables are the heavy-duty electrical cables that connect the utility company’s power lines (the service drop overhead or service lateral underground) to a building’s primary metering and main disconnect equipment.

Main feeder lines are the circuit conductors that transmit power from the output main service equipment or main panelboard to secondary distribution points. An example would be from the main panel box to a secondary distribution box in a garage.

For aluminum wiring remediation, a crimp method can be used. A specialized system cold-welds a short piece of copper wire (“pigtail”) to the aluminum wire using a high-pressure tool.

Another method is a mechanical splicing connector, specifically UL listed for aluminum-to-copper transitions. This uses micro-splices with internal screws and antioxidant paste to safely secure the aluminum-to-copper connection.

UL-listed remediation methods can substantially reduce risk. These include use of connectors and devices specifically evaluated for aluminum conductors, such as CO/ALR (copper/aluminum revised) devices and approved repair systems installed by qualified electricians.

Verification of professional remediation and ongoing maintenance can be an important underwriting consideration when assessing buildings with legacy aluminum wiring.

DISCLAIMER: This information reflects the interpretation of MSO, Inc. with regard to NFPA Standards and Codes and other code sources. It does not represent these codes’ official position on the items discussed.

Subppanel box with feeder line