These circuit breakers come in different shapes and sizes, depending upon the manufacturer of the circuit breaker box. Single-pole breakers supply and protect 120-volt branch circuits from the service panel. They have a handle to manually turn the circuit breaker both on and off. This handle has a specific amperage labeled on it that is the maximum amperage allowed to pass through the circuit breaker before it trips.
Single-pole circuit breaker is designed to trip if the amperage rating labeled on the handle is exceeded. This occurs when the circuit is either overloaded or a short circuit occurs somewhere within the branch circuit that it is connected to. An overload occurs when too many things or to great a load is connected to any one circuit. A short circuit occurs when the hot wire is forced to connect to either the neutral or ground wire within a circuit. It could be a motor winding shorting two wires together or as simple as a hot wire falling off of a terminal within an outlet box and hitting the ground wire.
Single-pole circuit breakers supply many things throughout the home including general lighting, outlets, furnaces, electric baseboard heaters, fans, all types of 120-volt appliances, curling irons, hair dryers, vacuums and many other everyday 120-volt electrical appliances. But the list doesn’t stop there. They control outdoor lighting, electronic devices, air conditioners, and those power tools many of you use in garages and out buildings.
So you see, single-pole circuit breakers are a very important part of your overall electrical circuit protection safety devices and they do their job very well. Many single-pole circuit breakers have a clear peep sight that shows red when the circuit breaker has tripped. This along with the handle moving to a center position gives you a clear indication of which breaker has had trouble on it. The nice thing about circuit breakers is that they can easily be reset from a tripped state.