What you need to know before opening the panel

Replacing a circuit breaker is a task you can do yourself if the breaker has simply tripped and won't reset, or if it has failed and needs to be swapped out. However, the work involves opening your electrical panel, which contains live current even when the main breaker is off. If you are not confident working inside the panel, or if your breaker keeps tripping repeatedly, call a licensed electrician instead — the cost of a service call is less than the cost of a serious injury.

The process itself is straightforward: turn off the main breaker, remove the panel cover, unscrew the failed breaker from its slot, disconnect the wire attached to it, insert the new breaker, reconnect the wire, and screw it back in. The whole job takes 10 to 20 minutes once you have the right replacement breaker in hand. The hardest part is identifying which breaker you need, because breakers come in different amperages and types, and installing the wrong one can damage your wiring or create a fire hazard.

Key Takeaways

  • A tripped breaker that won't reset by flipping the switch back on usually means the breaker itself has failed and needs to be replaced, not just reset.
  • You must know the amperage and type of the breaker you are replacing — this information is printed on the breaker itself or in your panel directory.
  • The main breaker must be switched to the off position before you open the panel, but the panel itself still carries live current, so avoid touching the main breaker terminals or the bus bars.
  • Most residential panels use standard breakers rated at 15, 20, 30, 40, or 50 amps, and you must buy an exact match for the slot you are filling.
  • If a breaker trips more than once after replacement, the problem is likely an overloaded circuit or a short in the wiring, and you should have an electrician inspect the circuit.

Identifying the breaker you need to replace

Before you go to the hardware store or electrical supply shop, you need to know what breaker to buy. Open your electrical panel and look at the breaker that has tripped or failed. The amperage rating is printed directly on the toggle switch — it will say 15A, 20A, 30A, 40A, 50A, or another number followed by the letter A. Write this number down.

Next, determine the type of breaker. Most residential panels use single-pole breakers, which control one circuit and take up one slot in the panel. If the breaker is wider than the others or spans two slots, it is a double-pole breaker, which controls two circuits or a 240-volt circuit. The package or label on the breaker itself will tell you the type. If you cannot read it clearly, take a photo of the breaker and the panel label with your phone and show it to the store staff — they can match it for you.

Write down the brand name of your panel as well. Common brands are Siemens, Square D, Eaton, and GE. Breakers are usually brand-specific, meaning a Square D breaker will not fit securely in a Siemens panel. The store staff can confirm whether a replacement breaker is compatible with your panel.

Turning off power and opening the panel safely

Locate your main breaker at the top or bottom of the panel — it is usually larger than the other breakers and may be labeled "Main" or "Service Disconnect." Flip this switch to the off position. The panel is now de-energized at the main level, but the terminals where the power lines enter the panel are still live. Do not touch these terminals or the large bus bars running down the sides of the panel.

Remove the panel cover by unscrewing the bolts or screws holding it in place. Set the cover aside in a safe location. Look inside and locate the breaker you need to replace. If you are unsure which one it is, check the directory printed on the inside of the panel cover — it lists which breaker controls which room or circuit.

Before you touch anything inside the panel, use a non-contact voltage tester to confirm that the breaker slot you are working on is de-energized. These testers cost $10 to $20 and are sold at any hardware store. Touch the tip to the breaker and the bus bar next to it — if the tester beeps or lights up, do not proceed. Call an electrician instead.

Removing the old breaker and installing the new one

Locate the screw on the right side of the breaker that holds it to the bus bar. Using a screwdriver, unscrew this bolt and set it aside. The breaker will now pivot slightly away from the bus bar. Gently pull the breaker straight out of its slot — it should slide out smoothly. If it does not, do not force it; stop and call an electrician.

Once the breaker is out, you will see a wire connected to the terminal on the end of the breaker. This wire carries power to the circuit. Loosen the terminal screw on the old breaker and disconnect the wire. Keep the wire in your hand or have someone hold it so it does not fall back into the panel.

Take your new breaker and insert it into the same slot, pushing it straight in until it seats fully against the bus bar. The breaker should click or snap into place. Reconnect the wire to the terminal screw on the new breaker and tighten it firmly — the wire should not move when you tug on it gently. Screw the mounting bolt back in on the right side of the breaker.

Restoring power and testing the breaker

Replace the panel cover and screw it back in place. Flip the main breaker back to the on position. The panel is now re-energized. Go to the circuit controlled by the breaker you just replaced and test it — turn on a light or plug in a lamp to confirm power is flowing.

Flip the new breaker to the off position to confirm it switches smoothly and does not feel stuck or loose. Flip it back on. If the breaker trips immediately or within a few minutes, turn it off and leave it off. This usually means there is a short circuit or an overload on that circuit, and you should have an electrician inspect the wiring and devices on that circuit before using it again.

When to call an electrician instead

Do not attempt this work if the breaker is difficult to remove, if you cannot locate or read the breaker specifications, if the voltage tester indicates live current in the panel after the main breaker is off, or if you are uncomfortable working inside an electrical panel at any point. Electricians are trained to work safely in live panels and can diagnose why a breaker is failing in the first place.

Also call an electrician if a breaker trips repeatedly after you replace it, if multiple breakers are tripping at the same time, or if you smell burning or see scorch marks inside the panel. These signs indicate a more serious electrical problem that requires professional diagnosis and repair.

Frequently Asked Questions

Can I replace a breaker while the main breaker is still on?

No. The main breaker must be off before you open the panel or touch any breaker. Even with the main breaker off, the panel terminals remain live, so do not touch them. If you are not confident turning off the main breaker safely, call an electrician.

What if I buy the wrong amperage breaker?

Installing a breaker with the wrong amperage can cause wiring to overheat and create a fire risk. If you realize you have the wrong breaker before installing it, return it and buy the correct one. If you have already installed it, turn it off immediately, remove it, and install the correct breaker.

Why does my breaker keep tripping even after I replace it?

A breaker that trips repeatedly usually means the circuit is overloaded or there is a short in the wiring. Do not keep resetting it. Turn it off and have an electrician inspect the circuit to find the cause before you use it again.

Do I need a permit to replace a breaker myself?

Permit requirements vary by location. Some jurisdictions require a licensed electrician to do any work inside an electrical panel, while others allow homeowners to do it themselves. Check with your local building department or code office before you start.