The Siemens 3RB1246-1EG20 is an overload relay rated 25...100 A for full motor protection, sized for S2/S3 contactor frames. It offers adjustable trip class 5...30, so you can match the thermal curve to the motor start profile — class 10 for standard starts, class 20 for high-inertia loads like fans or crushers. The straight-through main circuit design simplifies bus-bar or cable routing in the panel. Ground fault detection is built in, with monostable outputs signaling a ground fault at AC 110...120 V, 50/60 Hz. That means you get a dedicated alarm output without an external ground-fault module — useful for ungrounded or IT systems where a first fault must be annunciated, not just tripped.
This relay mounts to size S2 or S3 contactors, so it shares the same DIN-rail footprint and bus-bar alignment. The auxiliary circuit uses screw terminals — strip length per the manufacturer's recommendation, torque to the listed value on the nameplate. Reset is selectable: manual, automatic, or remote, which gives the panel builder flexibility for unattended restart or lockout-tagout schemes.