How to Replace a Circuit Breaker Fuse

A circuit breaker with all circuits, save for one, switched on.
  • 1 hours
  • Intermediate
  • 5-20
What You'll Need
Multimeter unit
Circuit breaker fuse of correct amperage
What You'll Need
Multimeter unit
Circuit breaker fuse of correct amperage

Circuit breakers are part of the main electricity distribution system within your home. They are found in the circuit breaker box—often referred to as the "fuse box." Fuses provide a safety mechanism that disconnects electricity supply to a circuit in your home if something goes wrong.

Circuit breaker fuses may need replacing if they repeatedly switch off for no apparent reason, if they refuse to reset, or if they do not switch off when they should. When you need to replace one, remember that electricity can be dangerous, so always exercise caution and show respect for electricity to avoid harm.

Step 1 - Open the Fuse Box

Wear rubber-soled shoes and ensure the floor beneath the circuit breaker box is dry to minimize the risk of injury. To start, remove the circuit breaker box cover by unscrewing the corners with a screwdriver. Then, make sure to push the main electricity switch, to the individual fuses, into the “off” position.

Step 2 - Identify Fuse to be Replaced

Each different type of fuse problem will show different symptoms upon inspection. Obviously, the push-lever of a fuse that frequently trips will likely be found in the “off” position despite the rest being on.

A circuit breaker fuse that will not reset will be off and cannot be flipped back on; and finally, a fuse that refuses to trip when it is supposed to will probably show marks of overheating or damage.

Step 3 - Check for Current

Turn the damaged fuse off if it’s not already and set your multimeter to “Volt AC.” Rest one pin on the terminal screw of the faulty fuse and the other on the ground screw, which lies opposite in a row or bar at the side of the box. The reading should indicate no voltage, otherwise, you should not continue.

Step 4 - Remove the Fuse

To remove the circuit breaker fuse, you will either need to unscrew it or simply pull or lever it from its socket. The fuse will remain connected to either one or two wires. Detach these by loosening the terminal screws. Make a mental note, or write it down if you don’t think you’ll be able to remember, of which color wire attaches to which end of the fuse for later.

Step 5 - Check Fuse Amperage

It is important that the replacement circuit breaker fuse is of the same amperage (and voltage unit) of the original. You may wish to take the old fuse to the store in order to purchase the correct replacement.

Step 6 - Rewire and Insert New Fuse

Set the new fuse to the "off" position. Insert the original wires, in turn, into the terminals of the new fuse and tighten the retaining screws with a screwdriver. Push the new fuse back into its socket and, if it’s supplied with retaining screws, tighten screws after inserting them. Flip the lever switch on.

Step 7 - Reconnect Supply

Switch the circuit breaker fuse box back on and then replace the box cover; insert the screws and tighten them to finish.

Circuit Breaker Fuse FAQ

Can you replace a circuit breaker without turning off the main breaker?

You can replace a circuit breaking without turning off the main breaker...the same way you can reach into the oven and grab a pan without a potholder. Working on a circuit breaker without turning off the power is taking your life into your own hands.

Turn off the electricity before you start doing any electrical work or you could be making a fatal mistake. It is extremely dangerous to work on a circuit breaker without turning off the electricity and it's important to remember that even though something is possible, that does not mean it should ever be done.

How do I know if my breaker fuse is bad?

There are usually signs of a bad circuit breaker. There may be a burning smell or noticeable heat, for example.

Usually, the breaker will also trip often rather than staying turned on.

Can you replace a breaker fuse yourself?

You can learn how to replace a breaker fuse on your own as a DIY endeavor. It is recommended to work with a professional on some level, at least, even if only to have them check over your work and to ensure that you don't need to take out a permit with your local building code office in order to complete this work.

How do you know when a breaker needs to be replaced?

If a circuit breaker will not steadily stay on without tripping or you notice a burning smell around it, you should replace the breaker. You may also see rust or feel noticeable heat coming from the circuit breaker.

How long do breaker fuses last?

On average, breaker fuses last around 30 to 40 years before they need to be replaced.