Types of wiring in older homes

In this article series we list common old building electrical wiring system safety concerns and we illustrate types of old electrical wires and devices. This article series basic questions about assessing and repairing the electrical service, capacity, wiring type , condition, and safety in older homes. The oldest type of wiring system found in homes is called knob-and-tube, named for the insulating knobs and tubes are used to run the wiring along and through the house framing.

Knob-and-tube wiring was run as individual wires —one black hot wire and one white neutral . Wiring methods have changed over the years from knob and tube to flexible armored cable (Greenfield) to nonmetallic cable (NM), conduit (EMT), and underground feeder (UF) cable.

Every home makes has many different types of wire running through it.

Each has its specific use to accommodate the load.

Not every jurisdiction provides the same kind of electrical power. Ceramic tubes were inserted into holes bored in wall studs or floor joists, and the wires were directed through them. This kept the wires from coming into contact with the wood framing members and from being compressed by the wood as the house settled. Fuse over-current protection is still sometimes installed in these older homes. Once the amount of current flow exceeds what the size and type of wiring can handle, the wire will heat up and in . Cloth wiring is in old houses and is the predecessor to modern house wiring ( Romex).

There are essentially two types. The cloth wire without an extra ground wire disallow you from using three prong receptacles, without ground fault protection. Both the hot and neutral wires run.

This type of wiring is rarely used because it operates the same as old -style Christmas lights—when one light burned out, none would illuminate. All this wiring will be removed and replaced with correct safe wring that conforms to current. Plus, materials such as wire insulation can deteriorate over time. Like your veins, it is important that your electrical wiring be in good health. This protects your house against electrical damage and keeps your family safe.

Copper wire should last 1years or more, but the insulation around it will deteriorate sooner and is the determining factor in lifespan. Like antique furniture, older homes offer wonderful decorative details and craftsmanship. The quickest way to identify house electrical wiring is by its color. The helpful reality is that you really have only three types of wire to identify: hot, .