Which type of circuit breaker has no intentional delay when reacting to a fault?

An instantaneous trip circuit breaker is designed to react to electrical faults without any intentional delay. This type of breaker is engineered to detect high fault currents and quickly interrupt the circuit to protect against damage from conditions such as short circuits or overloads. The rapid response of instantaneous trip circuit breakers is crucial in preventing overheating and minimizing the risk of fire or equipment damage, ensuring safety and system reliability.

In contrast, delay circuit breakers incorporate a predetermined time delay to allow for temporary surges or fluctuations in current, which means they do not trip immediately. Thermal circuit breakers rely on heat generated by current flow to trip, thus they also have a built-in delay while they sense overheating conditions. Inverse time circuit breakers trip based on the magnitude of the fault current with a time delay that decreases as the fault current increases, meaning they too do not provide an immediate response to all fault conditions.