Home Wiring 101: Dealing with Circuit Breakers and Fuses

Electric switch on a  control panel at the home
(DepositPhotos)

You don’t have to be a master electrician to own a home, but every homeowner should know the basics about how the electrical system in their house works and what to do when it doesn’t.

Whether you plan on tackling electrical wiring problems around your house or prefer to leave them to the pros, resetting tripped circuit breakers and replacing burned out fuses is something every homeowner needs to know how to do.

Understanding Electrical Service Panels

Home electrical service panel.
Home electrical service panel.
An electrical service panel is a metal box mounted on a wall or on the outside of your house which contains either circuit breakers or fuses to control the wiring in your home.

The panel may also include a main breaker or main fuse to turn off all the circuits controlled by the panel. If not, the main for the house may be located at the electrical meter or elsewhere in your home.

The purpose of circuit breakers and fuses is to limit the amount of electricity (expressed in amperes or “amps”) allowed to flow through the wires of an electrical circuit to prevent fires and electrical shocks.

The maximum number of amps allowed before the breaker trips or the fuse blows is printed on the breaker or fuse, and usually ranges between 15 and 30 amps for standard 110-volt circuits.

Make sure you are dry and standing on a dry surface before working on an electrical service panel or doing any other electrical work.

Turning a circuit breaker off in an electrical service panel.
Turning a circuit breaker off in an electrical service panel.

How to Turn Power On and Off to a Circuit

Each circuit should be labeled next to the breakers or fuses or on the inside of the service panel door to indicate which breaker or fuse controls the wiring to each part of your home.

If the circuits aren’t labeled, you’ll have to the flip the breakers or unscrew the fuses one by one until you find the one that controls the circuit you want to turn on or off.

To turn the power off to an electrical circuit, flip the breaker switch toward the outside of the panel or unscrew the fuse. To turn power to a circuit back on, push the circuit breaker switch toward the center of the box or screw the fuse back in.

Single and double 20-amp circuit breakers.
Single and double 20-amp circuit breakers.

How to Reset a Tripped Circuit Breaker

When a breaker trips or a fuse blows, it’s usually due to a power surge beyond the rated amperage of the breaker or fuse. This could be the result of:

  • An overloaded circuit with too many electrical devices on it.
  • Faulty wiring, such as a short in a wire or a connection that’s loose.
  • Short in an appliance, light fixture, lamp, or other electrical device.
  • Lightning or a power surge from the main line leading into the house.

It’s also possible that the circuit breaker or fuse itself is defective and needs to be replaced.

It’s important not to repeatedly reset a circuit breaker or replace a fuse, since it’s usually a sign of a problem with the wiring which needs to be fixed to prevent a fire or electrical shock.

To reset a tripped circuit breaker:

  • Turn Off Electrical Devices: If the breaker tripped because the circuit was overloaded, turn off or unplug any electrical devices on the circuit before resetting the breaker to prevent it from tripping again.
  • Locate Tripped Breaker: The switch on a tripped breaker will be near the off position or between the on and off settings.
  • Turn Breaker Off: Switch the breaker completely to the off position (away from the center of the panel box).
  • Turn Breaker On: Flip the breaker back to the on position (toward the center of the panel box).
  • Test Circuit: Turn on a light fixture or lamp on the circuit to make sure the circuit has power.

If the circuit continues to trip, there is either a problem with the wiring that needs to be fixed or the breaker itself is defective and needs to be replaced.

7 COMMENTS

  1. Since my husband passed away and I’m the only one in the house, I’ve been switching off the breaker for the hot water heater. I’m gotten mixed messages if this is ok. Someone just told me I could wear out the switch if I do this too often. Am I making a mistake switching off the water heater at the box for a day or two?

  2. The first para could be easily misconstrued and it states: “An electrical service panel is a metal box mounted on a wall or on the outside of your house which contains either circuit breakers or fuses to control the wiring in your home.”

    For all homes I’ve ever seen the circuit breaker box is never outside. What is outside is the meter box, and most commonly the circuit breaker box is directly behind it on an interior wall. It is not too far away since it is a high power wiring.

    I’d like to suggest one diagnostic approach if early conclusion is a defective breaker, remove it with main power switch off, and replace it with another one in the paned with the same amp rating. This also goes for old fashioned fuses where it only needs to be unscrewed from the fuse socket.

    Rusty

    • Hi Rusty,
      Most breaker panels are located inside a house, but they can be mounted outside if a NEMA Type 3R enclosure is used. The house I used to live in had a combination meter and breaker box mounted on the outside wall.

  3. ABOUT THE SWITCHING HOT WATER HEATER off & on (to save electricity)…Whats the pros & cons on that ???? It saves about $20 mo. on electric bill. Whats a better way to go ?????WE have enough HOT water for 2 days.Turn on for 1 hr….then off again.
    THANKING YOU IN ADVANCE,
    Janie

    • Paula and Janie,
      Circuit breakers are not designed to act a regularly used on/off switch, and doing so will cause the breaker to wear out prematurely over time. If the water is hotter than necessary, start by turning the breaker to the water heater off and then turning the thermostat on the hot water heater down to 110 to 120 degrees. Another option is to have a switch rated for the number of amps the water heater draws installed in the electrical line that powers the water heater.

  4. My A/C outside unit fan motor went out. I had a license service company replace the motor. It ran all summer long never shutting it off. Finally it cooled down in sept., turn thermostat off. I notice the outside fan unit did not turn off. I now think it never did cycle off. Our electric bill was higher than normal. Anyway, had to shut it off by breaker switch. It has always shut off by thermostat and the only thing that changed was the replacement motor. I called service company and she said it was 4 months ago and I said yes we never shut it off. I asked her to ask the guy who installed it if he could had crossed wired something. She asked and called back and said its a possibility but if it is not our fault the 90 service fee will be charged. I don’t trust this company, I feel that they would make up something to keep from owning up. Also if the unit never cycled off that new motor ran 24/7 and its life expectancy is now less. Is there a way I can look at wiring and know if it was miswired?

  5. I am glad that you mentioned to be dry and stand on a dry surface when working with electrical panels. This is not something I would have considered. I have an unfinished basement that I am working on and I do not feel comfortable working on the electrical wiring by myself. Finding an electrician will make finishing these renovations a lot easier.

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