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How Many Breakers Can I Put In A 100 Amp Panel

All the previous generation homes used fuses and fuse boxes as a means of protecting the circuits from overcurrent. But as the demand for power increased over the years, we moved on to a much safer and more reliable Circuit Breaker Panel. During the 1970s, a 100 Amp Circuit Breaker Panel became common for residential wiring systems. Nowadays, the average home size has increased quite a lot and power consumption has risen steeply. So, many homeowners are upgrading to a 150 amp or a 200 Amp panel. But slightly older homes are still rocking the 100 Amp circuit breaker panel. Did you ever wonder “How many breakers can I put in a 100 Amp panel?”.

This is a common question many homeowners ask if they are looking to upgrade their circuit panels. If they feel that the existing 100 Amp panel can squeeze a couple of circuits (with corresponding breakers), then they can avoid the hassle of upgrading their panel.

Before that, you must know how many circuit breakers you can fit in a typical 100 Amp Service Panel. We will try to find the answer to this question in this guide.

A Brief Note on Service Panel (Breaker Panel or Circuit Panel)

The Main Service Panel (other names include the Circuit Breaker Panel, Circuit Panel, Breaker Panel, or Control Panel) is the heart of a residential electrical system. It is a large metal box that sits recessed into a wall, usually near the main electric meter but sometimes in the basement, utility area, or garage.

Here is a list of the three essential jobs of a circuit breaker panel:

  • It acts as the main distribution hub for all the individual circuits (or branches) in a residential electrical wiring system.
  • It houses all the circuit breakers of the individual circuits and they act as the main over current protection devices.
  • It also houses the main control switch (the master breaker or switch) using which you can connect or disconnect the incoming electrical power from your utility to all the individual branch circuits.

Parts of a Circuit Breaker Panel

There are several components of s service panel that perform specific functions. Let us briefly see about them.

  • Main Circuit Breaker: The main circuit breaker or simply the main sits at the top of the breaker panel. The service wires coming from the utility go through this breaker. As a result, the main circuit breaker also acts as the main disconnect switch.
  • Hot Bus: The main circuit breaker connects to a pair of copper or aluminum strips or legs. We call them Busbars. As each bar carry the “Hot” connection from the main breaker, they are known as Hot Bus. We have to plug the circuit breakers into these bars.
  • Circuit Breakers: Just below the main circuit breaker, you can see a lot of circuit breakers that control individual branch circuits. Large power system such as water heaters, dryers, water pumps and heating systems, etc. have their own circuit breaker. Some other circuits are the kitchen, bathroom, living room, etc.
  • Neutral and Grounding Bus: There are a couple of bars on the outer sides of both the Hot Buses. These are the neutral/ground buses. They act as a common return point for the current.

The electricity from the utility enters your home through the meter and then into the main circuit breaker. This breaker feeds the electricity to the two hot buses which connect to the circuit breakers.

From the circuit breaker, the electricity flows through the circuit, then through the load, and back to the circuit breaker. It finally enters the neutral bar and back to the utility.

Circuit Breakers

Before Circuit Breakers, it was the time of Fuses. But since the late 1960s, all service panels started using circuit breakers as they are much more reliable. A Circuit Breaker is a safety device that protects an electrical circuit from short circuits or overload.

You can think of the circuit breaker as an electrical switch. You can manually turn it on and off and this will enable or disable the electric current to that individual circuit.

But the beauty of the circuit breaker lies in its ability to monitor the current flowing through the circuit and “trip” if it detects an overload or a short circuit.

Here’s how a circuit breaker operates. It has a special metal strip that heats up and bends as the overall current in the circuit increases. If you overload the circuit, the metal strip bends so much that it trips a switch and stops the flow of electric current through the entire circuit.

You have to remove the heavy load that overloaded the circuit and then reset the circuit breaker to restore the power.

The main and important characteristic of a circuit breaker is the amount of current it can handle before it trips. We mention this current in Amps and often describe it as the size of the Circuit Breaker.

Here are some common circuit breaker sizes that you can find in a service panel:

  • 15 Amp Circuit Breaker
  • 20 Amp Circuit Breaker
  • 40 Amp Circuit Breaker
  • 50 Amp Circuit Breaker
  • 60 Amp Circuit Breaker
  • 100 Amp Circuit Breaker
  • 200 Amp Circuit Breaker

Of these, the 15 Amp and the 20 Amp circuit breakers are very common for controlling individual branch circuits. The 100 Amp and 200 Amp circuit breakers are not used for individual circuits but rather as main circuit breakers.

How Many Breakers Can I Put in a 100 Amp Panel?

As we mentioned earlier, a 100 Amp Circuit Breaker Panel is the bare minimum nowadays. Depending on the size of your house or the number of electrical and electronic appliances you intend to use, the main service panel can be of different sizes such as 150 Amp, 200 Amp, or even 400 Amp.

If you feel that your existing 100 Amp Panel isn’t sufficient for your electrical needs and you are looking to upgrade, it is best to check whether there is any scope to add additional circuits to the current 100 Amp Service Panel.

In this way, you can avoid expensive panel upgrades and simply add an extra circuit or two to the existing 100 Amp Panel.

Another scenario is you are installing a new 100 Amp Main Service Panel. So, you want to know whether you can use it to create all the necessary circuits in your home. Or should you invest in a much larger and more expensive 200 Amp Panel?

The answer to all these questions lies in the answer to another important question, “How Many Breakers Can I Put in a 100 Amp Panel?”.

If you take a look at popular panel manufacturers, a typical 100 Amp panel supports at least 20 Circuits. So, this type of panel can support 20 regular or standard Circuit Breakers.

As per NEC, the maximum number of breakers that a 100 Amp Panel can hold is 42. So, you can find 100 Amp Service Panels that can hold 20, 24, 32, and 40 circuit breakers.

Note that these numbers are the theoretical limit of the number of breakers you can put in a 100 Amp Panel. This doesn’t mean you can use all the breakers running at full load all the time.

According to NEC, the current draw from all the breakers in the main service panel should not exceed more than 80% of the panel’s (or the service) capacity, which is 100 Amps in this case.

How Much Load Can a 100 Amp Panel Handle?

Assuming you have a 100 Amp Service coming from your utility and a 100 Amp Main Breaker Panel, then another question is how much load can the 100 Amp Service or the 100 Amp Panel can handle?

We have seen earlier that 15 Amp and 20 Amp circuit breakers are the common choices for the individual branch circuits.

If you have a 20 Amp Circuit Breaker, then at 120 Volts, the maximum load this circuit breaker can handle is 2400 Watts.

In this way, you can make a rough calculation on the power consumption of all the electrical appliances and allocate dedicated breakers to very high-power appliances such as Ovens, Dryers, Air Conditioners, etc.

Irrespective of the number of circuits, make sure that your 100 Amp service and the 100 Amp Panel don’t exceed more than 80% of its capacity.

This means, all the individual circuits and respective circuit breakers together should consume up to 80 Amps (ideally) in a 100 Amp Service with a 100 Amp Circuit Breaker Panel.

Upgrade from 100 Amp to 200 Amp Panel

Small and medium homes are usually supplied with a 100 Amp service. As a result, these homes have 100 Amp Service panels to distribute the electricity to the rest of the home.

If you are expanding your home or if you feel that your 100 Amp Service isn’t sufficient for all your electrical and electronic appliances, then you have to upgrade to a 200 Amp Service.

Naturally, when you want the 200 Amp Service from your utility, you need to have the right equipment, which is a 200 Amp Main Breaker Panel in this case.

A 200 Amp Service will give enough headroom to accommodate all your large appliances. Just upgrading from a 100 Amp Service to a 200 Amp service with a new 200 Amp Panel can cost you anywhere between $1,500 to $2,000.

The cost can be even more if you want to relocate your service panel or redo the wiring. But the extra power from a 200 Amp Service can help you in the long run as you don’t have to worry about any future appliances or even while selling the house.


The Main Circuit Breaker Panel is an essential part of a residential electrical wiring system. It is responsible for taking the electricity supply from the utility and distributing it to different parts of the house.

To help do this, the Service Panel houses several circuit breakers that control individual branch circuits such as living room, lighting, bathroom, kitchen, garage, heater, water pump, dryer, etc.

A 100 Amp Service with a 100 Amp Breaker Panel is very common in slightly older homes. If you are looking to add additional circuits to your existing 100 Amp Panel, then an important question rises “How many breakers can I put in a 100 Amp Panel?”.

In this guide, we saw the basics of a typical main service panel (or the main circuit breaker panel) along with its essential parts.

After that, we saw a brief note on circuit breakers and also their different sizes. Then, we answered the question “How many breakers can I put in a 100 Amp Panel?”. We also saw how you should calculate the load you can put on a 100 Amp Service and the 100 Amp Panel.

If you feel that we missed something or you would like us to add additional information, please let us know in the comments section below. It will not only help us but also other readers.

One Response

  1. If change wire from 50Amp to 100AMP
    Will main service hold 3 dedicated service 100Amp each
    Since the feeder is for 200Amp?

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