A bus bar is a terminal (usually a thick copper strip) in the electrical system to which various components are wired, creating a single point of contact from which voltage can be distributed. Bus bars simplify the wiring system and, in aircraft with multiple bus bars, prevent a short or other electrical problem from wiping out the entire system. Most general aviation aircraft have two bus bars, separating the avionics from the other electrical components. Some aircraft also have an essential bus switch that can be turned on to quickly shed load from all but the most critical electrical components.