circuit breaker

circuit breaker
    n 1: a device that trips like a switch and opens the circuit
         when overloaded [syn: {circuit breaker}, {breaker}]
    

circuit breaker \cir"cuit break"er\, n. (Elec.)
   A device contained within an electrical circuit designed to
   interrupt the circuit when the current exceeds a preset
   value; it is sometimes called a {contact breaker}. Its
   function is to prevent fire or damage to the circuit or the
   devices on the circuit which could be caused by excess
   current, such as that caused by a short-circuit. It differs
   from a {fuse} in not having a conducting element which melts
   (see 2nd {fuse}, n.). Circuit breakers are designed to be
   easily reset, i. e. to reclose the circuit after it has been
   opened by the circuit breaker; this is usually accomplished
   by simply moving a switch back and forth. They are commonly
   used in buildings to protect individual electrical lines, and
   are often contained in groups within a box called a circuit
   breaker panel, which divides the current from a main
   electrical line into multiple circuits each protected by a
   separate circuit breaker. Less commonly they may be found on
   individual devices.
   [PJC]