Siemens 3TH4373-0BB4 Electronic Overload Relay

Siemens 3TH4373-0BB4 is an auxiliary contact block (73E) for DIN EN 50011, designed to mount with Siemens motor-contactor assemblies to expand control circuitry. It provides 7 normally open (NO) and 3 normally closed (NC) contacts, all actuated by a DC coil rated at 24 V DC. The module uses screw-terminal connections for secure wiring and is intended for DC operation in industrial control panels. By adding this 73E accessory, the main contactor gains additional signaling and interlocking points, enabling more elaborate control logic and PLC feedback in motor-drive and automation applications. This device represents the standard auxiliary-contact configuration used with Siemens automation equipment to distribute control signals while maintaining compact panel layouts.