Old house or new, you should be familiar with the type of wiring you have. Building standards change periodically, so make sure yours is up to code.
An electrician apprenticeship starts as little as 100 hours in a trade school lab, all the way up to universities offering 4 year degrees. That’s how much training and knowledge goes into becoming a licensed electrician. But understanding the basics of your home electrical wiring doesn’t have to be so intensive.
If you’re doing a simple DIY project around the house, you should know about the types of electrical wire in a home. There are also common coding, sizing, and labeling you’ll need to understand.
We’ve broken down everything you need to know about house electrical wire in this basic guide.
Why You Need to Know About Your Home’s Electrical Wiring
If you’re doing any type of project around the house, understanding your home electrical wire can make the job easier. You need to know about the types of electrical wire when you’re:
- installing new wiring and need to know what type of wire to use
- looking for electrical problems in your home (i.e. knowing the circuit that wiring belongs to can help you determine the cause of an issue)
- doing any electrical repairs or remodeling
Remember that any changes to your home electrical wire must be up to code. That means following the National Electrical Code as well as any local ordinances in your geographic location.
The latter tend to be more strict and should be followed closely to avoid errors.
Not following code increases the risk of hazards like fire. It can also cost you if you ever decide to sell your home and it’s caught by a home inspector.
The Basics of Home Electrical Wire
Before we dive into the types of electrical wire, there are some basic terms, labeling, and coding you should know about. Understanding these can make your trip to the hardware store that much easier.
Cable vs. Wire
The terms ‘cable’ and ‘wire’ so often used interchangeably that you might think they’re the same thing. But they’re not.
Electrical wire is any material that conducts electricity. They’re the individual conductors inside a jacket. They’re either insulated or bare.
A cable, on the other hand, is the combination of two or more wires. These wires are assembled together with a single jacket.
Cable-Sheath Color Coding
The outer sheathing of cables is color-coded. Cables are color coded to tell you about the size of the wires inside the cable. The color code also indicates the cables amperage.
Below are the color and their associated size and amperage:
- Black. 8 or 6-gauge wire, 45 or 60 amp circuits
- Orange. 10-gauge wire, 30-amp circuit
- Yellow. 12-gauge wire, 20-amp circuit
- White. 14-gauge wire, 15-amp circuit
Gray cables are underground feeder (UF) cables. All UF cables are gray. In order to know the gauge of the wire and the circuit information, you’ll have to check the cable-sheath labeling.
In addition, cable-sheath color coding is a relatively new innovation in the electrical industry. It wasn’t introduced until 2001 and companies aren’t obligated to use it. For that reason, you should always check with the manufacturer if the color coding complies with current standards.
Wire Color Coding
Unlike cable-sheath color coding, wire color coding is standard for all conductors. Home electrical wire is usually limited to the following colors:
- White. This is a neutral wire. It’s responsible for completing a circuit by carrying the current back to the panel.
- Black/Red. These are hot wires. That means that they carry electrical current from the panel to a device. The device might be a receptacle, light fixture, switch, or an appliance.
- Bare/Green. This color code indicates ground wires. A ground wire comes into play when there’s a ground fault. These wires create a path for the current to return to your home’s breaker, blow a fuse, and cut off electricity.
There are other colors of wire but there are the most common ones you’ll find in your home.
Knowing what each wire represents can help you understand how the various wires in your home contribute to your electrical system.
Labeling
Both wires and cables use labeling to tell you about the wire size, the material, the number of wires inside a cable, the type of insulation, and other special ratings. The labels are printed on the wire insulation or on the outer sheathing of a cable.
Wire Size
The size of the wire refers to the diameter of the conductor itself. It’s regulated by the American Wire Gauge system. In a nutshell, the smaller the wire is, the larger the gauge.
It’s imperative that the size of the wires you choose matches the amperage of the circuit. If they don’t match, the risk of short circuits and fires is greatly increased.
But how do gauges and amperages work together?
The gauge of a wire determines how much current-carrying capacity it has. Current-carrying capacity is essentially the amount of amperage a wire can safely handle.
In terms of home electrical wire, you’ll usually be working with 12 or 14-gauge wire. But for appliances, you’ll be using 10, 8, or 6 gauge. Things like stoves, water heaters, dryers, and air conditioning units use these larger gauges because they require a lot of amperages.
Stranded Wire vs. Solid
When you need to push the wire through a conduit, you need solid wire. But when you need to pull wire through a conduit, you might think about using stranded wire. Because it’s more flexible, it’s easier to get around corners or hard-to-reach areas.
Types of Electrical Wire in a Home
There are a number of different types of wiring and cable found throughout a home as well as around it. We’ll go through the most common types in more detail below.
Non-Metallic Cable
In homes built after the mid-1960s, the wiring is relatively standard.
The common type of home electrical wiring is non-metallic, or NM, cable. You may also know it as Romex cable, which is the most popular brand name of this type of electrical wiring.
NM cable is usually three or more individual conductors. Those conductors are wrapped in a flexible plastic jacket also known as sheathing. In one NM cable, you’ll usually find a hot wire, a ground wire, and a neutral wire.
NM is used for dry, interior home electrical wiring. That includes appliances, switches, light fixtures, and outlets. The most common sizes of NM found in modern homes are:
- 14-gauge, 15-amp circuits
- 12-gauge, 20-amp circuits
- 10-gauge, 30-amp circuits
- 8-gauge, 40-amp circuits
- 6-gauge, 55-amp circuits
Alternatively, your house electrical wires may be installed in a conduit. This is a flexible metal or plastic tubing. It’s usually used in situations where wiring is exposed.
Regulations Around NM Cable
There are a few regulations around NM cable that you should be aware of.
First, they cannot be used in residential construction that exceeds three stories in height. Strictly designed for homes, they can’t be used in commercial constructions either.
NM cable is designed as a permanent home electrical wire system. They shouldn’t be used as a substitute for extension cords. They also shouldn’t be used to substitute the wiring for your appliances.
You must use the proper support for the cables where necessary. You cannot support them with nails or stables. Anything that could damage the cable is not permitted as support and they must be secured at intervals of less than 4.5 feet.
Armored Cable
As mentioned, local ordinances on house electrical wire tend to be more strict than national codes. And in some communities, Romex or NM cable is not permitted for use. Instead, these communities use armored cable or AC.
Also known as BX, this type of electrical wire dates back to the early 1900s, but it’s still in use today. AC wiring is designed with flexible metallic sheathing. This provides extra protection for the conductors inside.
Similar to NM cables, AC isn’t permitted for use in commercial buildings or residential constructions exceeding three stories. The regulations surrounding support are also similar.
Underground Feeder Cable
While AC and NM cables are designed for dry, interior conditions, you need a cable that’s okay for use outdoors or in wet conditions. This type of cable doesn’t need the protection of walls, floors, and ceilings.
That’s why when you need to run wire underground or to outdoor projects, you use an underground feeder, of UF, cable. This type of electrical wire is also non-metallic cable and it can be buried under the ground without conduit.
It can also get wet without any issues.
Similar to NM cable, UF cable is made up of three wires.
One hot wire, one neutral wire, and a bare ground wire. They appear similar to NM cable as well, but the sheathing around UF cable is a solid plastic that you can’t roll between your fingers.
Metal-Clad Cable
If you have some home electrical wire running through unfinished areas like basements, they need a stronger outer surface. That’s where the metal-clad cable comes in.
It’s used in unfinished areas where the wiring is exposed to the possibility of physical damage.
Low-Voltage Wiring
When you have a circuit that uses less than 50 volts, you might use low-voltage wiring.
This type of house electrical wire is used for items that don’t require a lot of electricity. This includes doorbells, most thermostats, and landscape lighting.
You’ll find low-voltage wire ranges in size from 12 to 22-gauge. It’s usually insulated or covered in cable sheathing.
Phone and Data Wire
If you still have a landline telephone, you have special wiring for it. The same can be said for your internet connection.
Both your phone and internet use low-voltage wires. Your telephone and data cables can contain anywhere from four to eight wires. But the most common type of cable used for this purpose is Category 5, or Cat 5.
Cat 5 cables are eight wires that are wrapped together in four pairs. This is actually the most efficient type of cable for a phone and data transmission.
Electrical Wiring Channels
Well not exactly a home electrical wire, wiring channels definitely come in handy with home wiring systems.
Also known as electric channel raceways or plastic channels, these extruded profiles help you protect and organize all of the types of electrical wire in your home. But they can also be used in commercial, medical, and industrial applications.
Made in a square, round, flat, rectangular, domed, or completely customized shape, electrical wiring channels have a range of applications. In your home, you use them to prevent tangling, wire damage, and disorganization.
They may also help prevent trip hazards when you have cables running along floors and walls.
More Help Understanding Your Home and its Electrical Wiring
Home electrical wire systems are complicated. But understanding its components can help you diagnose problems, complete repairs, plan for renovations, and keep your wiring up to code.
The first things you need to know about your house electrical wire are the basics. You should know how size relates to amperage, how cable-sheath and wire color coding works, and how to read a cable or wire label. But you should also know the difference between wires and cables and when you use a stranded versus solid wire.
After that, you have to know all of the types of electrical wire in your home.
These include everything from the NM cables powering your outlets to the UF cables powering your outdoor lamp posts. But your home may also use AC cable in place of NM, as well as metal-clad cable in unfinished places and low-voltage cable for low-power receptacles.
But knowing and understanding your home electrical system doesn’t necessarily translate to being able to repair or change it.
For that, you might need the help of a professional. If that’s the case, check out our wide range of electrical services and give us a call to see how we can help you.