Circuit breakers straddle the hot bus bars, and if there’s an overload on the branch circuit—the affected circuit trips and automatically stops the flow of electricity to that branch in your home.  Breakers also serve as the starting points for the electricity which runs to various areas of your home. This explains the need to have labels (with the names of rooms or major appliances) next to the individual breakers, or overcurrent protection. Each circuit has hot wires, black and/or red, feeding into the breaker, as well as a neutral wire, white, that connects to the neutral bus. Your white wires should not be installed into a breaker without identification it is considered a hot wire. These wires exit the breaker box and go on to provide power for the area(s) of the home needing service. Single pole breakers consist of one switch, and handles 120 volts, and can be either 15 or 20 amps. When wiring the breaker, there should be a bit of slack as well. The extremely tight pull over time on the wire could eventually become loose and worse yet fall off the breaker and energize the panel creating immediately a dangerous, if not deadly situation.