Siemens' UL 1077 Supplementary Protectors are designed to provide additional protection along with a branch circuit protection device. Since our Supplementary protectors are made to trip faster than a standard UL 489 Circuit Breaker they are able to provide additional protection for more sensitive devices inside the panel. Supplementary protectors can used in a number of industrial applications such as to provide selectivity for multiple motor control circuits on the secondary side of a control transformer or power supply by allowing the user to quickly find the problem circuit should a fault occur without having to shut down all of the other control circuits. Supplementary protectors may also be used as a local disconnecting means inside the panel when a branch circuit protection device is already present. Supplementary protectors are equipped with a delayed overload/time-dependent thermal release (thermal bimetal) for low over currents and with an instantaneous electromagnetic release for high overload and short-circuit currents. The thermal trip point on all versions is 1.13 to 1.45 times the supplementary protector rating.