Siemens 3TX44 auxiliary switch block is a four-contact accessory for EN 50011 contactors, delivering additional control signals via screw-terminal connections. Within the 3TX44 family, the 3TX4440-0A variant provides four normally open (NO) contacts, while the 3TX4404-0A variant offers four normally closed (NC) contacts, expanding the control circuit on compatible Siemens relays. The block is rated for insulation up to 690 V and measures about 44 x 42 x 57 mm, designed for mounting on compatible Siemens contactors to add auxiliary switching capability.
