During your finding of what is a tamper resistant outlet, you must have learned enough on the 2 things which are sub panel and main breaker. These parts are different in purpose and sometimes need to ensure a safe circuit line in a home. 

And to plan a proper electrical line at your apartment, you’ll need both of these sometimes. Now coming to the point, which is ‘does a sub panel need a main breaker’ or if one can excuse it. In the next segment, I’ll clarify on it along with some extra details that might help you. 

Invest your 5 minutes to read this guide without skipping anything. Let’s drive into the main subject…

Does A Sub Panel Need A Main Breaker?

Sub Panel and Main Breaker:

According to most experts, the subpanel doesn’t need a main breaker as the main panel already has a feeder breaker. But, to stop power during a short circuit, it’s possible to add a main breaker in the subpanel.

Before giving further explanation of does a subpanel need a main breaker, I’d like to break down what’s subpanel and the main breaker is for those who are still unaware.

  • Starting with the subpanel, it’s a smaller box that provides power (from the main panel) to particular places of the apartment. And, this does have its own breakers.
  • The main breaker is a large circuit that stops power in order to prevent damage due to overcurrent.

Do you have the main breaker in your home subpanel? If not, then be sure to hop for a safer option that is excellent in quality and durability.

My Recommendation

One of the best replacement circuit breakers in the store for sub-panel boxes is the Connecticut Electric UBIP2100. Not only it is safe for electrical projects but also assures quite good quality.

Is A Main Breaker Required in A Panel?

Just like chassis wiring vs power transmission, the topic is popular among novices, especially those who want to add a new circuit line in the garage or basement. 

Is A Main Breaker Required in A Panel

It’s not compulsory that a subpanel require a main breaker. Why? Well, the main panel contains a feeder breaker which does a great job to prevent harm due to short-circuit.

But the subpanel is compatible with the main breaker so that anyone can add in order to increase the safety of the power distribution process (from the main panel). For that, you need to maintain the code given by NEC aka National Electrical Code

What Size Breaker Do I Need for A Sub Panel?

To understand the right size of the main breaker, you need to check the NEC 225.39 rule as it describes all the sizes based on the installation type.

  • For one-circuit installation, NEC gives allowance to use one 15 amps breaker load limit. But if you add 2 circuit breakers, the rating of size is not 30 amps with 2-wire.
  • For the dwelling of a family, you can use 100 amps of breaker size with 3-wire.
  • If you have a separate plan to add a breaker in the basement or other purposes, then add 60 amps size.

Equation Procedure: Wattage / Voltage = Amperage.


Suppose your circuit wattage is 8000W and voltage is 240V then,

Amperage = 8000W / 240V

= 33.33A

How To Add a Main Breaker to A Sub-Panel?

If you think about what to do with unused live electrical wires and need to attach the main breaker on a subpanel, then make use of it. Be sure to gather tools before starting the procedure.

  • Take out the bonding screws. Find the wiring harness.
  • Detach the lugs (near to the place where the red and black color wire is connected).
  • Next, attach the breaker and then insert the nut.
  • Join the red and black wires to the lugs (on the upside of the breaker). And, put back everything to its place.

Note: To attach the main breaker in the subpanel, follow the ‘6 breaker rule’ which is suggested by NEC. It means you can add the main breaker which can’t take more than 6 switches power. 

Frequently Asked Questions:

1. How many amps can a subpanel be?

By and large, the subpanel doesn’t have a restriction. This means you can add 60 amps to 100 amps at your home. But, if your subpanel is 200 amps, then be sure the power feed doesn’t go over 160 amps.

2. When can a main lug panel be used?

You can use the main lug panel if the main circuit breaker is placed remotely. And to do that, just ensure both of them are 200 amps rated in power.

3. Does a subpanel need a ground rod?

Yup! If the sub-panel is outside of the apartment, then it doesn’t need a ground rod with wirings. And, you don’t have to use a ground rod if the sub-panel is placed inside the apartment. Only the wiring is required.

How To Install a Sub Panel Start to Finish!

Wrapping Up

The electrical line is a confusing thing that requires good knowledge on matters like the one we talked about today, does a sub panel need a main breaker. Or else, shock or fire issues will enter the apartment when hitting the switch or attaching the plug.  

Be sure to do some extra study before adding the main breaker in the sub-panel. Hope this guide was informative to present what you were looking for along with some questions which people search often. On that account, we’re ending this guide here. Goodbye!