Reviewed by Arthur Kavanagh
Updated May 1, 2023
You plug in your new vacuum and turn it on. The lights in your kitchen promptly shut off and the digital clocks on your appliances disappear. Is it a power outage?
Nope, it’s probably a tripped breaker. Breakers are the safety switches that automatically shut off power to part of your home when the electrical circuit overloads. Homes have many breakers, and they all live together in the electrical panel — the “brain” of your home’s electrical system.
Here’s our complete guide to home electrical panels:
An electrical panel (a.k.a. breaker panel) is a metal box with a door, usually built into a wall in an out-of-the-way corner of your home. Inside, you’ll find all your home’s breaker switches.
You can toggle breaker switches on and off. They’ll also shut off automatically when there’s too much electrical current running through them — that’s what they’re for.
Within the electrical panel, you’ll find a main circuit breaker that controls the power to the entire house. You’ll also see individual breakers, each responsible for providing the electricity to a specific part of your home. Each breaker should have a label that identifies the area of the house it controls.
Some older homes don’t have breakers; they have fuses instead. If you have a fuse box, you won’t see any switches on your electrical panel; you’ll see screw-in fuses. If your home still uses a fuse box, you may have difficulty getting insurance, or you may have to pay a higher rate. We’ll address fuses and home insurance further down the page.
The power to your home comes through an electrical meter outside, which routes power to your electrical panel. You can shut off this main feed of electricity using the main breaker in your electrical panel. Your main breaker also tells you the amperage of your electrical service (amperage is the strength of the electrical current).
Home electric services in Canada range from 60 to 400 amps. Most electrical codes mandate at least 100-amp service.
Home insurance providers are often interested in your home’s amperage. If it’s less than 100, you might need to update your system. Sub-100 amperage could make it difficult for you to find insurance for your home; at the very least, you’ll need to pay a higher rate.
Electrical panels are metal boxes, typically grey in colour. They’re usually embedded in a wall.
Electrical panels have doors (or at least, they should). Behind the door, you’ll find an assortment of wires and switches — those switches are your breakers.
Electrical panels are normally in an out-of-the-way part of your home. Basements, storage rooms, laundry rooms, or garages are all common places to install an electrical panel. In older homes, you might even have to look outside the house to find your panel.
In apartments, the most common places to find the panel is right inside the unit near the entrance or in the bedroom, behind the door.
Most homes have just one electrical panel, though some may have subpanels, especially homes that have multiple living units. See the common questions section for more on subpanels.
Circuit breakers trip (that is, shut off) when the circuit is overloaded. They’re safety devices, meant to prevent damage to electrical devices or to the home itself. If the breaker didn’t trip and shut off the power, overloaded circuits could start fires or electrocute someone.
Each breaker controls one circuit; each circuit usually corresponds to a room or an area of the house. Power-hungry devices like electric ranges or air conditioners might have their own breaker.
A breaker is designed to carry a certain electrical load; if the electrical load grows too large for the breaker, it shuts off. This happens if you have too many devices plugged into one circuit, for example.
There are assorted sizes of breakers depending on how much electricity they need to handle. Like the home’s electrical service, individual breakers are divided by what amperage they can handle. Breakers range from 15 to 200 amps; most are either 15, 20, or 30 amps, though.
Breakers also have voltage ratings; a single circuit breaker is normally provides 120 volts — the typical amount needed for lights, TVs, etc. A double circuit breaker is rated for 240 volts. This is for the big appliances that draw a lot of power, such as a stove or electric dryer. Large, power-hungry appliances like stoves or refrigerators should each have their own dedicated breaker.
When the breaker trips, all you need to do is flip the switch to reset it. In older homes with fuse boxes, you can’t just reset it; you need to replace the whole fuse if it blows.
The cost to upgrade your home’s electrical panel varies widely depending on the scope of the work, but you should expect to pay (very roughly) $2,000 – $2,500. That’s for 100-amp service, though. More commmonly, homeowners already have 100-amp service and need to upgrade to 200. The cost for that is approximately $3,500 to $5,000.
The only way to be sure about the cost is to have an electrician (or better yet: 3 different electricians) give you detailed quotes.
There are two reasons you’d want to upgrade your electrical panel: your service doesn’t provide enough power for your home, or you have fuses instead of breakers.
If your home has a fuse box, or your electrical service is below 100 amps, you should upgrade. Even if you already have 100-amp service, you might need to upgrade to 200- or 400-amp service, as many homes are running at capacity on 100-amp service.
If you’re not sure your electrical panel is enough, you can have an electrician estimate your service usage and tell you if you need an upgrade or not.
Building codes govern electrical panels. For safety reasons, panels need to adhere to many standard requirements.
Building codes in Canada are different in each province and municipality, but generally speaking, they dictate:
There are tons of other technical electric code requirements for breaker boxes. But, unless you’re an electrician, you don’t need to worry; work on breaker boxes and electrical wiring should always be done by a qualified person.
As mentioned earlier, a circuit breaker will trip if the circuit has become overloaded.
For instance, you’re using your blow dryer, while the TV and the desktop computer are running at the same time. Even if they’re all plugged into different outlets, they could be on the same circuit. This may result in too much power being drawn, and the breaker will trip.
If you’ve tripped a breaker, here’s what you should do:
Now you should be able to use your electrical devices again.
Just remember, don’t use them all at the same time. Or you can move one of them to a different outlet. If you’ve shut off the offending electrical item, and the circuit breaker continues to trip, there could be another problem.
If you have a breaker that trips often (or multiple breakers), it may be a capacity issue.
If it’s just one breaker causing problems, you can solve it by removing some electrical devices from that circuit and putting them on a different circuit. If it’s a case where you don’t have enough circuits (for example, all the outlets in your kitchen are on one circuit), you may need an electrician to rewire your breakers or add more circuits.
In some cases, an electrician can add subpanels or tandem circuits to spread power usage around more effectively.
However, it may also be that you’ve simply reached the limit of your home’s electrical service. If you have breakers tripping often, or you find that your electrical panel and the walls around it are warm to the touch, you might need to upgrade your whole electrical system to 200- or even 400-amp service — a big, potentially expensive job (but sometimes a necessary one).
In the short term, you can address capacity issues by not running too many devices at once (especially power hungry devices like HVAC systems, water heaters, or washer/dryer pairs.
Corrosion of electrical panels or the wiring around them is a sign that moisture is present. Moisture and electricity are not a good mix (obviously).
However, if you only find corrosion or rust on the metal door or frame of your panel, it may not be a significant problem — moisture in the air can cause rusting. Just sand the panel down, prime it, and re-paint it.
Corrosion on the breaker switches or electrical wiring is much more serious, though. It can be a sign that moisture is seeping into your electrical system, perhaps from the outdoor meter. If you see corroded wires or switches, call an electrician.
This situation is a bit more serious.
When one electrified wire (called a “hot” wire) touches a neutral or other hot wire, it will cause a short circuit. That can happen when mice or other animals damage the wiring, or when you plug in a device with damaged circuitry. It can be hard to find the cause of a short circuit.
Short circuits should immediately trip a breaker. If you reset a tripped breaker and it instantly trips again, a short circuit is most likely to blame.
If you think an electrical device is causing the short, shut off the breaker that controls power to that outlet. Check the power cord to see if there are any melted areas or other damage. Look at the outlet itself, and check for a burning smell or any dark discoloration. These are all signs of faulty circuitry. If you unplug the device and the breaker resets properly, that device was likely causing the short.
If you can’t find a specific appliance that’s causing the short, there may be some crossed wires in your electrical system. You should call an electrician to find and fix elusive short circuits.
Similar to a short circuit, a ground fault happens when a hot wire touches a ground wire, or any thing else that’s grounded. “Grounded” means electricity can flow through that object to the ground.
Ground faults often happen when electricity meets water. Say, for example, you’re using a hair straightener and you drop it in a filled sink. That would cause a ground fault and trip a breaker.
As is often the case in bathrooms, your outlet may have a ground fault circuit interrupter, or GFCI.
GFCIs are special devices that immediately cut power if they detect a ground fault (even faster than the breaker can).
GFCIs are part of electrical outlets and cut power to anything plugged into that outlet. You can identify a GFCI by the black and red buttons on the outlet. These buttons are for testing and resetting the GFCI.
If you trip your GFCI, unplug everything from it and press the reset button.
You should test your GFCI a few times a year. Just plug something in, turn the device on, and then press the test button on your GFCI outlet; it should immediately cut power to the device. If not, call an electrician to replace your GFCI.
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Like everything else in your home, a little maintenance goes a long way.
Always keep the cover on your electrical panel, and make sure it’s kept closed. This will prevent dust from entering, or other damage occurring.
Have an electrician do regular maintenance about once every three years.
They will take the cover completely off the panel and inspect the breakers. They’ll check all the connections and do a thermal check to find unusually high temperatures. Heat and electrical problems often go together.
You can even put your hand on the cover of the electrical panel; it should feel cool. If it’s hot, shut off the main breaker, and call an electrician.
Many people think that the electrical panel will last as long as the house does; that’s not always so.
Connections can loosen, and operating near or over capacity can shorten the electrical panel’s lifespan. In humid locations, your electrical panel can suffer from corrosion. Dust can shorten the lifespan as well, if it gets into the switches and wiring.
Electrical panels have a lifespan of about 20-30 years. Some may last even longer, up to 50 years, if they get regular maintenance.
However, you may need to upgrade your panel well before it dies if your home’s electrical needs change. For instance, if you’re adding a hot tub, pool, or another high energy installation.
DIY tinkering can also reduce the lifespan of an electrical panel. If someone other than a licensed electrician makes changes to the panel, it could cause problems over time. Always get the requisite permits and hire a qualified electrician to do work on your electrical panel.
Labelling the breaker switches inside your electrical panel is important. You need to be able to tell what you’re affecting when you switch the power to a circuit on or off.
Breakers usually don’t have enough room on them to label them directly. Instead, you can either label them with a marker or stickers next to each breaker. You can also draw up a diagram and tape it to the back of the electrical panel door.
When you’re labelling the different circuits, avoid using shorthand or nicknames; the labels should be clear to someone who doesn’t live in the house (or to a future owner, if you ever move). For example, a label that says “Steven’s room” doesn’t mean much to an electrician; “upstairs west bedroom” would be clearer.
Some circuits control only single appliances, like a dishwasher or an air conditioner. You can label these with the name of the device.
Hopefully, whoever installed your home’s electrical panel did some labelling for you. If you’re starting with a totally blank breaker box, though, here’s how you can narrow things down:
If you’re struggling to find what’s connected to which breaker, the amperage ratings on each switch can help you narrow it down:
Your insurance company will want to know what kind of electrical panel you have. If you have an up-to-date panel with circuit breakers and 100-amp service, they shouldn’t take issue.
If you have a fuse box or sub-100-amp service, though, many insurance companies won’t insure your home, or at least will require you to get an electrical inspection before they do.
Why is it difficult to get insurance with fuse boxes?
Fuse boxes are outdated technology, and easily tampered with. For instance, some people may replace a 15 amp fuse with a 30 amp fuse to allow more electricity to run through without blowing it. Overloading circuits like this can cause all sorts of problems, fires being one of the worst.
Wires are limited in how much electricity they can convey; if you force too much juice through a small wire, it’ll start generating heat and become a serious fire hazard.
Another trick is sliding a penny into the fuse box in place of a new fuse. It should go without saying, but don’t do that! Without a fuse to cut power during an overload, there’s an enormous risk of your electrical system causing a fire.
Modern electrical panels have circuit breakers in place to prevent wires from overheating.
This is what insurance companies will want to know. A circuit breaker panel with 100-amp service tells them your home has a modern electrical system that’s likely to be safe.
Insurers take a calculated risk with each home they insure. Outdated electrical panels with 60-amp service or fuses aren’t enough to handle the electrical needs of a modern home.
If you’re not sure whether you have an adequate electrical panel, ask an expert. You should know exactly what you have before shopping around for home insurance.
For more information on electrical panels and house insurance, get a free quote on your home insurance by clicking the button at the bottom of the page.
There are a few warning signs that point to a bad circuit breaker:
If you have a multimeter and you know how to use it, you can test each of your breaker switches to see that they’ve got the right amount of electricity running through them.
Yes, you do need a permit to make any changes to your home’s electrical panel.
Most upgrades to your electrical panel require you to hire an electrician. Often, the electrician can take care of the permit for you, and for major work like upgrading the panel, it may be necessary to have an electrican in place to pull the permit.
Rules for permits are set by individual municipalities. Check your town or city’s website to see how they handle electrical permits.
An electrical subpanel is a smaller electrical panel that controls a specific area of the house. They’re also called service subpanels or circuit breaker subpanels. They look pretty much the same as the main electrical panel: a metal box in the wall filled with switches.
Subpanels are connected to the main panel and divide up the main electrical service to the lot. For example, if your house has a separate rental suite in the basement, that suite’s electricity would be on a separate subpanel. If tenants in a home live in a separate suite, they need access to their own breakers in case they trip.
Subpanels have master power switches just like main panels, but it’s also possible to shut off the power to a subpanel from the main panel.
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About the expert: Arthur Kavanagh
Arthur has been a natural leader since the age of 18, having completed a 4-year electrician apprenticeship and overseen crews of up to 60 electricians. He is the founder of his own premiere electrical contracting company: Kato Electrical Inc.
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