electrical panel

What is a Branch Circuit

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 breaker

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

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.

kitchen with room circuits

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.


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.

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