It is good safety practice to label all power outlets so that their controlling circuit breakers are easy to locate. Employees can go straight to the tripped circuit breaker for resetting. If power needs to be interrupted on certain circuits it is good to know which power points will be affected. Also in the case of RCD testing, the RCD circuit breaker must be tripped and it must be known which power points and equipment will be taken off line. Three Pin Testing can trace all circuits and attach a label on the power point showing the distribution board and circuit number it is supplied from.