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What is a Service Panel?

Mary McMahon
Mary McMahon
Mary McMahon
Mary McMahon

A service panel is an electrical box which takes power from a utility and routes it to various circuits within a structure. The service panel is often located close to the electrical meter, and it is an important component of an electrical system. People should familiarize themselves with the location of the service panel in their homes so that they know where to go if there is a problem with the electrical system.

Structures attached to an electrical grid get what is known as a “service drop,” a connection to the grid which allows the structure to receive electrical power. The size of the service drop varies; a basic household service drop, for example, may be 100 amps. Larger service drops are used for structures like factories, which need far more power to meet their needs.

In an old fashioned service panel, fuses are designed to trip if there is a short circuit.
In an old fashioned service panel, fuses are designed to trip if there is a short circuit.

The service drop travels through the electrical meter, allowing the utility to measure how much power people are using, and then into the service panel. It usually hits what is often known as a “main breaker” first. Having a main breaker is important because it allows people to cut power to a structure with a single breaker. Then, the power is distributed among a series of circuits which are also controlled by breakers. These can include dedicated circuits such as those used for water heaters and stoves, which usually need their own circuits because of high energy draws.

Electrician at service panel.
Electrician at service panel.

Service boxes are sometimes referred to as fuse boxes. This is a reference to the fact that historically, service boxes used fuses as a safety measure. In the event of a problem with the current, one of more fuses would blow, cutting off power and reducing the risk of fire, shock, and other adverse events. Modern service panels usually use breakers, which have the same function as fuses, but can be reset after they are tripped for safety, rather than needing to be replaced.

Service panels are more commonly known as breaker boxes or fuse boxes in the U.S.
Service panels are more commonly known as breaker boxes or fuse boxes in the U.S.

It is very important that work on the service panel be performed by a licensed electrician or a homeowner who is very experienced with handling electricity. The service panel can be extremely dangerous to work on. It is also important that people use the service panel to cut power to circuits they are working on, and check those circuits with a voltage tester before starting work. If a breaker trips or a fuse blows, especially repeatedly, an electrician should be brought in to determine why, in case there is an underlying problem with the circuit which poses a safety risk.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a HomeQuestionsAnswered researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a HomeQuestionsAnswered researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...

Discussion Comments

orangey03

I needed to come in early to work for a week, so my boss showed me how to turn the lights on in the office. I had to turn two switches to get the lights in the entire room to come on.

I was surprised by how sturdy and hard to flip those breakers were! I really had to push to get them to budge.

I guess this is a good thing, though. They wouldn't want people turning the lights on and off just by bumping into the breakers.

DylanB

@lighth0se33 – That is a good idea. I never thought of doing that.

I only touch the service panel when my roommate needs to install a ceiling fan or something like that. We have each breaker labeled so that we don't have to search for the right one by turning them all off and on until we see the lights go off in the room where we will be working.

lighth0se33

I rent a home, and I got my landlord to show me how to work the service panel before I moved in. I wanted to know how to shut power down to the whole house in case of an electrical problem.

Not too long afterward, a bad thunderstorm came through and made the power flicker on and off. Some of my appliances were struggling to stay on, and I knew this couldn't be good for them.

I went out into the utility room and shut off the main breaker. I didn't turn it back on until I saw the neighbor's porch light come on.

Oceana

I recall my dad telling me never to touch the service panel when I was a kid. So, I grew up with a fear and respect of service panels.

Now, I refuse to touch one. I make my husband do it instead.

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    • In an old fashioned service panel, fuses are designed to trip if there is a short circuit.
      By: Willee Cole
      In an old fashioned service panel, fuses are designed to trip if there is a short circuit.
    • Electrician at service panel.
      By: Lisa F. Young
      Electrician at service panel.
    • Service panels are more commonly known as breaker boxes or fuse boxes in the U.S.
      By: auremar
      Service panels are more commonly known as breaker boxes or fuse boxes in the U.S.