Galvin Power is reader-supported. When you buy via our links, we may earn a commission at no cost to you. Learn more

How to Change Main Breaker Live? Learn It Safely in 10 Minutes

Written by Edwin Jones / Fact checked by Andrew Wright

how to change main breaker live

Learning how to change main breaker live pays off if you want to save money hiring an electrician to do it for you. However, you have to make sure you don’t compromise your safety while doing so. Working hot isn’t exactly a job for an apprentice electrician, after all.

If you’re brave and confident enough with your skills, I’ve gone ahead and laid out the usual safety precautions and steps I take when doing it in this post. These include the equipment I use, removal of the former breaker and installation of the new one.


Make Sure to Prepare These Tools Before Starting

These tools are just as important in keeping you safe while getting the job done.

  • Insulated screwdriver
  • Insulated gloves
  • Electrical shockproof helmet

An important note: I actually don’t recommend you replace the main breaker without turning off power since doing so poses a much higher risk of electrocution and fires. Way higher.

Even master electricians choose to kill the power as long as possible, especially if you’re doing a 100 amp main breaker replacement because there’s practically no valid reason to do it live, unless you’re servicing industrial and commercial establishments.

How I Go About With Hot Breaker Replacement Work


Step 1. Put on Your Safety Gear, Check the Breaker, and Consider Removing the Panel’s Cover

Remember: you’re installing a circuit breaker in a live panel, so put on all your protective gear before starting. You may also want to check the main breaker for tell-tale signs of damage due to loose connections as they can cause electrical shocks.

Another preparatory tip I suggest is to remove the cover of the panel so it won’t interfere with your work. I’ve heard instances of electricians hitting their head on it, so it’s really worth taking the time to remove them for now.

Step 2. Turn Off the Breakers and Disconnect the Main Breaker and Its Conductors


I always begin by turning off all breakers on the panel with the busbar or you can just turn off all the breakers one by one if that’s how your panel is set up.

In my usual Zinsco breaker replacement or other jobs that involve outdated panels, I gradually remove the conductors. Use a screwdriver to disengage one then, once disconnected, position the wires in such a way that it won’t come in contact with any unprotected part of your body. Afterward, work on the second one until you can now remove the original breaker.

A tip to make the job easier: You may already attach the wires to the new breaker that you’re going to use so you’ll remove any chance of touching it accidentally.

Step 3. Install the New Breaker

If you’ve changed the main breaker in that but shut down the power supply first before doing so, know that there’s no difference from that from here on. You’re wearing the appropriate gear so you can safely replace the breaker without turning off power.

It should slide easily in place even if you have already attached the conductors. It should be set and screwed firmly. Otherwise, you’ll have to make sure that it is, and that’s when it gets tricky with hot work since you’ll only be upping your risk of electrocution until it’s installed properly. This is precisely why I shun working with live panels.

If you’re encountering resistance, it’s best to check for damages on the busbar that may have been caused by a ground fault or short circuit issues. If that’s the case, why not just replace the outdated and dangerous panel like Zinco with a new one? That’s the safest and smartest choice based on my experience.

Step 4. Check for Loose Wires and Test the New Breaker with a Multimeter


Look out for and attach any loose wiring that you may have missed to connect, especially if they’re meant for the new breaker.

Assuming you got the new circuit breaker in place without hammering it on, it’s time to test it using a multimeter (if you are newbie, click here to learn more how to test a circuit breaker with a digital multimeter) . Make sure that the voltage reading is right. If you want to learn how to do this, this video should help you brush up your multimeter diagnosis skills in no time:

If that’s all in the green, then consider your job done. You can now replace the cover. Whether you’re going to give yourself a pat on the back for doing such a daredevil act is entirely up to you.


How’d you like my guide? To sum things up, can you change the main breaker live and how to change main breaker live? Yes, but it’s very impractical, and you’ll basically be putting yourself and anyone you’re working with at unnecessary risk of injury and even death.

Exercise extra caution if you’re going to go ahead with the steps and pointers I shared here. They’re backed by numerous experienced electricians so I always keep them in mind when I have no choice but to do live work. Thankfully, that’s been a rare occurrence.

5/5 - (3 votes)