Your house's electrical system is made up of a series of circuits. Each circuit powers a different part of your house. Some rooms may even have more than one circuit; for example, your kitchen may have one circuit for a refrigerator and another for a stove. That's because a refrigerator can be a heavy pull on a circuit when the compressor turns on. If one of those circuits keeps tripping the circuit breaker or parts of it don't work, then you likely have a short circuit and you need to have an electrician come to check it out for you.
How a Circuit Works
When a circuit is under power, it is a closed circle. It starts at the circuit breaker, runs to its area of the house, and then ends up back at the circuit breaker. If the circuit breaker senses a power surge or there is too much of a power draw going through it, the circuit breaker will turn off the circuit so that no damage will happen.
Each circuit has sub-circuits that are connected to it. Those smaller circuits are connected to light switches, outlets, and other such things. Those circuits aren't complete unless something is plugged into the outlet or the light switch is flipped on. If those smaller circuits have problems, they may be able to trip a breaker built into those circuits, like a GFCI, otherwise, their power surges go out into the larger circuit and can cause the larger circuit to trip the circuit breaker. If the smaller circuits are continually tripping their circuit breaker or causing the larger circuit to trip, you have a short circuit. But how can you figure out what part of the circuit is causing the problem? That's where an electrician comes in.
How an Electrician Finds a Short Circuit
There are several steps that the electrician will go through. The first thing they will do is observe the circuit while it is working. They do that by using the circuit normally. When it trips the circuit, they will ask you to turn everything off and unplug all electrical devices. Then the electrician will turn the circuit breaker back on. If the circuit continues to work, they will slowly start adding things back in until the circuit trips again. Generally, the last thing turned on or plugged in before the circuit trips is the problem. The electrician will try to determine whether the appliance or light is causing the short. If that's not the problem, then they will check to see if the outlet or wiring is the problem.
If you are interested in electrical training, contact HVAC Technical Institute or a similar organization.