Circuit breakers in power strips react only to overcurrent

摘要

In addition to an ON/OFF switch, most, if not all, power strips - technically called relocatable power taps (RPTs) - include circuit breakers. Some of those circuit breakers are part of the ON/OFF switch and a user may not even know a circuit breaker is present, while other circuit breakers are a separate component with a telltale reset button. In both cases, however, a bimetal senses an overcurrent condition, typically 15 amperes for an RPT, and trips the breaker, thereby interrupting power to the loads connected to the device. For a circuit breaker built into the rocker switch, turning the switch on closes its internal contacts, one of which is affixed to a bimetallic arm. When excessive current is drawn through the switch, the bimetal heats until it reaches its tripping temperature, causing the bimetallic arm to deflect and separate the contacts. This interrupts power and pushes the rocker switch to its OFF position. Since the action of the bimetallic arm turns off the switch, even when the arm cools, the switch remains off until someone resets it manually.