Aluminum Wiring

Aluminum Wiring 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 led 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. In addition, the presence of single-strand aluminum wiring may void a homeowner’s insurance policy. Homeowners should talk with their insurance agents about whether the presence of aluminum wiring in their home is a problem that requires changes to their policy.

Knob and Tube Wiring

Knob-and-Tube Wiring Knob-and-tube (K&T) wiring was an early standardized method of electrical wiring in buildings, in common use in North America from about 1880 to the 1940s. The system is considered obsolete and can be a safety hazard, although some of the fear associated with it is undeserved.

Facts About Knob-and-Tube Wiring: It is not inherently dangerous. The dangers from this system arise from its age, improper modifications, and situations where building insulation envelops the wires. It has no ground wire and thus cannot service any three-pronged appliances. While it is considered obsolete, there is no code that requires its complete removal. It is treated differently in different jurisdictions. In some areas, it must be removed at all accessible locations, while others merely require that it not be installed in new construction. It is not permitted in any new construction. Many insurance companies will not insure houses that have knob-and-tube wiring due to the risk of fire be sure to check with your insurance provider as exceptions are sometimes made for houses with such systems that have been deemed safe by an electrical contractor.

Ground-Fault Circuit Interrupters (GFCIs)

What is a GFCI? A ground-fault circuit interrupter, or GFCI, is a device used in electrical wiring to disconnect a circuit when unbalanced current is detected between an energized conductor and a neutral return conductor. Such an imbalance is sometimes caused by current "leaking" through a person who is simultaneously in contact with a ground and an energized part of the circuit, which could result in a lethal shock. GFCIs are designed to provide protection in such a situation, unlike standard circuit breakers, which guard against overloads, short circuits and ground faults.

Arc-Fault Circuit Interrupters (AFCIs)

Arc-fault circuit interrupters (AFCIs) are special types of electrical receptacles or outlets and circuit breakers designed to detect and respond to potentially dangerous electrical arcs in home branch wiring. AFCIs function by monitoring the electrical waveform and promptly opening (interrupting) the circuit they serve if they detect changes in the wave pattern that are characteristic of a dangerous arc. They also must be capable of distinguishing safe, normal arcs (such as those created when a switch is turned on or a plug is pulled from a receptacle) from arcs that can cause fires. An AFCI can detect, recognize and respond to very small changes in wave pattern.