What is branch circuit wire?

You’re trying to set up your home’s electrical network and came across a branch breaker. But what is a branch circuit breaker?

The definition of a branch circuit breaker is a tool that delivers and guides the appropriate current to a connected electronic device. It also comes in different types and amperage ratings to fit different electrical demands.

Continue reading to gain additional insight into branch breakers.

What Is a Branch Electrical Circuit Breaker?

Generally, a branch breaker manages the electrical power output of specific locations in a property. It usually connects to outlets with relatively light power requirements, but may serve appliances with high current demands as well.

Take note that other circuit breakers in the same electrical panel won’t become affected if one branch circuit breaker trips. Also, it’s important to mention that an electrical branch circuit comes in different variations.

1. Amperage

An individual branch circuit typically provides the appropriate electrical demands based on the assembly. These requirements often follow the voltage rating of each particular branch circuit breaker.

Upon looking at this voltage reading, you’d be one step closer to identifying the unit’s amperage rating. However, it’s also possible to verify the amperage by looking at an electrical diagram.

For instance, 120-volt branch breakers often come in 15- to 20-amp ratings. On the other hand, 240-volt branch circuit breakers usually have amperage readings ranging from 30 amps and higher.

2. Types

According to the National Electrical Code (NEC) Article 100 Section 210.3, branch wiring generally has four types:

General purpose: 120-volt circuit breakers are used to supply and control electricity for relatively small and/or portable electronics like lighting fixtures.
Appliances: As their name implies, branch circuits under this type are ideal for providing and managing power to dedicated appliances.
Individual: An individual branch circuit sends and oversees the flow of electricity to one piece of electronic equipment (e.g., motor or heater).
Multi-wires: This type of branch circuit wiring often has multiple ungrounded conductors connected to another grounded or neutral conductor.

3. Purposes

Typically, the function of a circuit breaker, particularly a branch one, is to control and supply power to connected electrical devices in a residence or business establishment. However, branch breakers also have other functions.

For instance, single-pole branch circuits can provide protection against fires, lightning, and power surges.

Frequently Asked Questions

1. What Are The Components Of A Branch Circuit Breaker?

Branch circuit breakers generally consist of five main parts, which are:

Frame or shell
Interrupting structure
Terminal connections
Tripping unit
Operating assembly

Take note that each component has its main function. For instance, the operating assembly is in charge of opening and closing the contacts. On the other hand, the tripping unit closes the circuit upon detecting an abnormality in the current.

2. What’s The Difference Between A Main Circuit Breaker And A Branch Breaker?

You can typically find the main circuit breaker sitting at the top of the electrical service panel. This device supplies and controls the current running through the branch circuits.

So, you can turn off the main circuit breaker to remove power deliverance to branch breakers in the same panel. But you can turn off a branch breaker without significantly affecting the main breaker.

3. Why Does Main Breaker Trip And Not The Circuit Breaker?

The main breaker tripping before branch circuit usually happens if the fault current falls below or equal to 6,000 amps. If so, the branch circuit breaker will open or remain functional while the main breaker will close.

4. Can You Split A Branch Circuit?

It’s possible to split a branch circuit by forming a letter “T” with the wiring. You may need to splice the existing wires in the branch circuitry to accommodate your property’s specific electrical demands.

Conclusion

Now that you’re at the end of this post, you should have a better idea than before as to what is a branch circuit breaker. Remember, branch breakers are responsible for the electrical deliverance and management of connected electronic devices.

Also, keep in mind that different CBs are available on the market. For example, you can purchase a 120-volt branch breaker with a 20-amp rating, but you can also buy and install a 240-volt 50-amp model.

I am Andrew Wright. I established this blog after eight years of experience designing, installing, and maintaining electrical power systems. I love my job, and I have always wanted to offer others the necessary help so they can take care of their houses.

Every home has an electrical box, usually in the garage or it may be in a basement, utility room, or even a closet. Inside this box are the circuit breakers that control the power to the house. What is a branch circuit? It is the wiring inside the electrical panel and they provide 120-volts for outlets and fixtures while there are branch circuits that provide 240-volts for larger appliances. Branch circuits run throughout the home providing power.

Let’s take a look at why you need to know about branch circuits, amperage, types of branch circuits, other electrical areas to be concerned about, and when to contact a professional.

Why You Need to Know About Branch Circuits

The electricity for a home starts from the outside. The main service wires come from the utility line or underground feeder wires and connect to the electrical panel. The power coming in from the outside belongs to the electric company. However, once it is inside the electrical panel, it then feeds the electricity throughout the home.

It does this through the individual branch circuits that are divided into 120 volt branch circuits for outlets and fixtures, and 240 volt branch circuits for appliances.

Amperage for a Branch Circuit

Everything that is electrical has amps. A 120-volt outlet can support up to 15 – 20 amps, while a 240-volt outlet can support up to 30, 40, or 50 amps. The amps that can run on a particular circuit are labeled on the circuit breaker. It is important that you don’t use a breaker larger than what can be handled on that branch circuit. Let’s take a look at the types of Branch Circuits for more of an explanation.

In older homes, circuits that were using a maximum of 15 amps were also using 14 gauge wires (which is thin, like the size of a dime) but that is no longer recommended. This is because the higher the amp rating, the larger the wires need to be. Circuits that use up to 20 amps using 12 gauge wire are recommended for general-purpose branch circuits in electrical wiring systems.

A 12 gauge wire’s thickness is like that of a nickel. When using thinner wires for larger amps, electrical fires can happen since the smaller wire cannot handle the load of electricity.

Confused yet? Here is a chart below of the number of amps that go with the proper size copper wire. Remember, each copper wire here is a branch circuit.

15-amps: 14-gauge copper wire

20-amps: 12-gauge copper wire

30-amps: 10-gauge copper wire

45-amps: 8-gauge copper wire

60-amps: 6-gauge copper wire

80-amps: 4-gauge copper wire

100-amps: 2-gauge copper wire

Types of Branch Circuits

Dedicated Appliance Circuits

Also called Individual Branch Circuits and usually serve power to only one appliance that is 120 or 240 volts. They are usually installed in the appliance and examples are stove, garbage disposal, clothes dryer, dishwasher, and refrigerator. Usually, any appliance that has a motor is served by this type of circuit. The amperage for these circuits can vary since it depends on the appliance.

Lighting Circuits

These are also known as multiwire. Lighting circuits are responsible for serving the lighting in rooms. Most homes have several lighting circuits for several rooms. Some homes will separate the lighting circuits from the outlet circuits so that if work is being done on the lighting circuits, then the outlet circuits can still work. This then means that a lamp can be plugged in.

Outlet Circuits

These are seen in a room or group of rooms and serve the purpose of plugging something into it like a printer, or a lamp for example.

Room Circuits

Sometimes all the lights and outlets in a room are on individual circuits. An example of this is the kitchen. The kitchen often has seven circuits and sometimes more. A kitchen needs to have :

Small appliance circuits– they are usually two 20-amps and 120-volts providing power to the outlets in the countertop areas and for portable plug-in appliances.
Oven – needs its own 120/240-volt circuit due to the electricity it uses.
Dishwasher and garbage disposal– both require their own 120-volt circuits. They can be 15-amp or 20-amp circuits, depending on the electrical load of the appliance. You will need to check the manufacturer’s recommendations to know for sure. The dishwasher circuit also requires GFCI protection. Be sure to check your electrical panel for the GFCI Challenger Breaker recall as well.
Refrigerator and microwave – each require their own 120-volt circuits. They should both be 20 amps on the circuit.
Countertop outlets – Any outlet within 6 feet of a sink must be GFCI-protected. Also, the countertop outlets should be no more than 4 feet apart.
Kitchen lighting – this is on a separate 15-amp (minimum) circuit.

Other Electrical Areas to Be Concerned About

Split Bus Panel

Homes that were built between 1965-1980 may have a split bus panel. This panel doesn’t have one switch to turn off all the electricity in the home. In fact, it requires the turning off of 6 switches! When you think about it, this takes a lot of time and can be dangerous. If you are not sure if you have this in your home, you can contact a professional to take a look for you.

Also check if you might have a Challenger GFCI recall or an FPE panel as both of these need to be replaced.

Double Tapped Breakers

Keep an eye out for double-tapped breakers. These are breakers that have two wires going in to them but are only made for one wire. Unfortunately, arcing and a fire can result.

Tamper Resistant Outlet

When you are checking in the home to see what type of branch circuits you have, look at the outlets or receptacles. A tamper resistant outlet won’t allow a child to stick anything into the slots and they close up and shut off access to the live electricity. Newer homes have these but older homes do not. You can replace these on your own or hire a professional.

Cloth Wiring

Check your home also for cloth wiring. If your house was built between the 1950s-1970s, there are chances you could have cloth wiring. This is something that you will need to contact a professional to replace as it is dangerous. It was added over the bare wire and rodents like to chew it making it even more dangerous.

When to Call a Professional

Call a professional when you have questions about branch circuits or any electrical issues in the home. Electricity is not easy to figure out how to fix and needs to be done by someone who is trained in that area. Call on a professional to give you a diagnosis and recommendations so your home will be functioning efficiently.

Conclusion

It is important to know about branch circuits so you can make sure your home is hooked up properly. You want to know that the amps are correct for the size of wire that is used.

You want to know how the home is powered by the main panel and how the circuits are divided, providing power and voltage to specific appliances or areas. We can take a look at your electrical panel and branch circuits when conducting home inspections in the Castle Rock and the Front Range areas.