When you have to install new wiring in your home or on your property, it’s essential that you choose the right wire or cable for the job. As a homeowner, this requires that you have some knowledge about the different types of electric wire available to you and what they’re used for.

The wiring in today’s modern homes is pretty standard, as is the wiring in most of the homes built after the mid-1960s. Of course, installing new wiring in your homes means conforming to your local building codes.

In this article, we’ll cover the six most common types of electrical wires and how to choose the right one for your next project. Keep reading to learn more.

Electrical Wiring 101

If you’re new to the world of electrical wire, it’s a good idea to familiarize yourself with the terminology.

For starters, an electrical wire is a type of conductor, which means it’ll be made out of metal. The wiring you find in homes is often made of copper, aluminum, or copper-sheathed aluminum. It will also either be solid or stranded.

Solid wire is thick and heavy and, therefore, best used for outdoor applications. Stranded wire is actually several thin, bundled wires that are compressed and insulated with non-conductive materials. They’re also lighter and more flexible, which makes them ideal for cramped and more complex geometrical spaces.

Additionally, most home wiring will be insulated — usually with a plastic coating. Ground wires, on the other hand, are typically made of solid copper and are either insulated with a green sheath or come completely bare.

The 6 Most Common Types of Home Wiring

The type of electrical wires you need for your home project will depend entirely on what that project is, the amperage it requires, the voltage it carries, and its location.

It should be noted that most of the larger wires in your home are likely carrying between 120 and 240 volts — which is also referred to as line voltage. Due to the high voltage, these can be very dangerous to touch. There are also low-voltage wires throughout your home that you can touch without worrying about shock or electrocution.

If you don’t know exactly the type of electrical wires you’re dealing with, it’s best not to touch them at all. Having said that, these are the six most common types of electrical wires you’ll come across in your home:

1. Nonmetallic Cable

romex nonmetallic cable wiring type in wall

Nonmetallic cables (NM for short) are a type of circuit wiring specifically designed for dry, interior locations. Often called “Romex” cables after the popular brand of NM cables, it’s the most common type of wiring found in homes today.

This cable consists of two or more individual wires wrapped up inside protective plastic sheathing. This sheathing helps isolate one or several current-carrying wires (hot), one neutral, and one ground wire.

The neutral wire is usually insulated in a white sheathing and the hot wire is in black to make installation easier. They also have a flat yet tubular shape, which allows them to run invisibly through walls, floors, and ceilings.

2. Underground Feeder Cables

Underground feeder (UF) cables are a type of NM cable specifically designed for wet locations — which means they’re a type of direct burial wire.

Direct burial wires are commonly used to supply outdoor fixtures and appliances with electricity. Therefore, these types of electric wires get buried underground.

Just like your standard NM cables, underground feeder cables contain insulated neutral and hot wires. They also contain a bare copper ground wire, and all wires are individually wrapped in solid plastic sheathing for better underground protection. Since they’re used for major circuit wiring, they tend to carry a high amount of voltage when turned on — which means you should proceed with caution when handling them.

3. THHN/THWN Wires

THHN/THWN Wires types connected to water heater

THHN and THWN are codes for two common types of stranded insulated wire. Both types of wire are single conductors, each with its own color-coded insulation that gets its protection from a tubular conduit made of metal or plastic.

Conduits are often used for unfinished areas of the home, like basements and garages. They’re also used for short exposed runs, such as the wiring connections for hot water heaters and garbage disposals.

The lettering of each wire type indicates the specific wire insulation properties:

  • T: Thermoplastic
  • H: Heat-resistant (HH means highly heat-resistant)
  • W: Rated for wet locations
  • N: Nylon-coated (for added protection)

The colored sheathing on these wires is also used to indicate specific functions within a circuit:

  • Black, red, & orange: Hot wires
  • White, brown: Neutral wires
  • Green & yellow-green: ground wires

Both THHN and THWN wires should never be handled while the circuit is running.

4. Low-Voltage Wires

thermostat low voltage wire type installed at home

Low-voltage wiring is used for circuits that only require up to 50 volts. This would include landscape lighting, sprinkler, system connection, speaker system, thermostat, and bell wiring.

Low-voltage wiring sizes also range from 22 gauge to 12 gauge and are typically made from copper or aluminum. They’re also often insulated in sheathing or combined in twisted pairs, like the type of wiring you see on a lamp.

Low-voltage wires are small and substantially different from your standard circuit wiring. However, it’s best to ensure your devices are turned off before handling them.

5. Phone and Data Wires

Telephone and data wiring are also low-voltage wires used for landlines and internet hookups. They’re usually made from copper and may contain between four and eight wires.

The most common type of phone/data wire is the Category 5 (cat %) cable, which contains eight wires wrapped up into four pairs. This type of wiring only carries around 30 volts, which is generally regarded as safe. However, they still need to be treated with caution as there’s always a risk of them coming into contact with your household circuit wiring.

6. Coaxial Cable

wire coaxial type next to composite wire types

The coaxial cable is becoming less common thanks to the rise of HDMI cables for TV and data transmission. However, they still exist and are easy to identify as they are round jacketed cables featuring an inner conductor (usually made of copper).

The tubular exterior jacket is usually white, and inside it contains a tubular conducting shield made of braided stranded wire. That’s usually black. Coaxial cables also carry a very low amount of voltage but still have the potential to cause a shock if they come in contact with another electrical source or current.

Need Help With Your Home’s Electric?

All the types of wiring used in the standard home and learning how to install each type can become complicated. More often than not, it’s best to call an experienced electrician when you have a wiring project for your home or property.

Electric City Corporation is here for all your wiring needs and more. Get in touch with us today for the electric services you need and for a free consultation!