What are the 3 types of wires?

Electrical wire is typically made of copper or aluminum, and these conductive materials are insulated as wires that bring electricity to various parts of your home. When you're installing new wiring, choosing the right wire or cable is half the battle.

When examining the old wiring in your home, identifying the wire type can tell you a lot about the circuit the wiring belongs to (for example, if you open a junction box and need to determine which wires go where). Wiring for modern homes is quite standard, and most homes built after the mid-1960s have similar types of wiring.

Below, learn the different types of home electrical wires to choose the right option for completing electrical projects accurately and safely.

Tip

Once you identify your houses wiring type, don't try to imitate it before consulting your local building codes. Any new electrical installation requires new wiring that conforms to local building codes.

Wiring Terminology

It helps to understand a few basic terms used to describe wiring. An electrical wire is a type of ­conductor, which is a material that conducts electricity. In the case of household wiring, the conductor itself is usually copper or aluminum (or copper-sheathed aluminum) and is either a solid metal conductor or stranded wire.

Most wires in a home are insulated, meaning they are wrapped in a nonconductive plastic coating. One notable exception is ground wires, which are typically solid copper and are either insulated with green sheathing or uninsulated (bare).

Warning

Many larger wires in your home carry 120- to 240-volt circuit voltage, often referred to as line voltage, and they can be very dangerous to touch. Several wires in your home carry much lesser amounts of "low-voltage" current. These are less dangerous, and with some, the voltage carried is so low that there is virtually no chance of shock. However, until you know exactly what kind of wires you are dealing with, it's best to treat them all as dangerous.

Difference Between Wire vs. Cable

While the terms wire and cable are often used interchangeably, technically a wire is one electrical conductor and a cable is multiple conductors, or a group of wires, encased in sheathing.  

Electric wires are typically made of aluminum or copper. They are either bare or insulated and typically covered in a thin layer of thermoplastic. If they have a thermoplastic sheath, then the thermoplastic is colored to indicate whether the wire is a neutral, ground or hot wire in your electrical installation. We discuss wire colors in a section of this guide. 

Cables contain at least a neutral wire, ground wire and hot wire that are twisted or bonded together. Depending on its purpose, the cable may contain more wires. The wires in a cable are insulated in their own color-coded layer of thermoplastic. The group of wires is then encased in an outer sheath to make up the single cable.