Electrical Service Panel (Breaker Panels) and how they work

Electrical Breaker (Service) Panels

Breaker panels tend be something that a lot of people stay away from (which is smart I might add). Unless you are properly trained and notified of the dangers inside the box, do just that. A breaker panel is almost like the brain of a house. It is the main station for which electricity comes into your house and then branches off to provide the many things that we tend take for granted. (light, heat, tv etc.)

Inside the breaker panel are a lot of different things. At its’ most basic there is a connection for the main power to come in, and branches to connect your circuits to. The hook ups for your main power are called bus bars, and on one are many connecting screws along the bar (bus bars…solid metal bars of varies sizes that conduct electricity). These screws are for your neutral wires which are the wires that return the current back to the panel to compete the circuit.

Also there are two more bus bars that provide the hot wires from your service (240 volts AC between them). These bus bars connect to your breakers (I will get to those after) and last but not least is your ground connector. The panel is grounded through itself (as it is made of a conductive metal) and this ground is transferred down into the earths ground via a buried grounding plate (see our grounding and bonding page).

The panel is filled with breakers, which are usually black and rectangular or square boxed shape. Inside breakers is a reusable tripping mechanism, which upon over voltage or over current will trip, opening that specific circuit and preventing sparking, electrocution, fires, etc. When a breaker is tripped it will usually display a small red sign letting the electrician know which breaker needs to be repaired and reset. The modern breaker is reusable as it can be reset after cooling down vice the old way of fuses which burnt out and had to be replaced.

Now back to the hot side. The panel has metal contacts which the breakers clip into to complete circuits. One side snaps onto the bus bar and the other is secured in a non electrical way. On the side opposite the bar is where you insert the wire into the breaker. Each branch has it's own breaker rated for load that it will be under. A 120 volt circuit will have a breaker that clips into only one metal bus bar, while a 240 volt circuit will clip into 2 (and be a larger breaker.) Some devices in your house use 240 volts and others 120.

An electrical panel also has what electricians call a “main breaker” which is the safety device towering over all other breakers in case of catastrophic failure, in which case the main breaker will trip and cut off power from the entire panel. It is very important to install an electrical panel with precision and neatness, remembering to label every circuit. And unless you are a trained electrician, don’t proceed to do any work inside your panel, instead…call a professional! Or go to school and become one yourself.

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