The Siemens 3RB2015-2SB0 is a SIRIUS solid-state overload relay rated for trip class 20E — that means it allows a 20-second thermal trip at 7.2× current setting, sized for motors with longer starting times like fans or high-inertia loads where a class 10 would nuisance-trip on start. It mounts directly onto a contactor (contactor mounting per), so it shares the same DIN-rail or screw-panel footprint as the contactor it protects; no separate enclosure needed for the overload block. The AC-3 rated maximum is 690 V, covering standard 400 V and 480 V motor circuits with headroom for 690 V drives.
Deployment context
This relay sits on the contactor's mounting surface, not on a separate DIN rail — the contactor carries both. The 45 mm width and 64 mm height match the standard SIRIUS contactor frame, so it doesn't add panel depth beyond the contactor's own. Depth is 73 mm, which is the total projection from the mounting surface. Wiring uses screw-type terminals for the main current circuit, accepting 0.5 to 4 mm² solid or 2x 0.5 to 2.5 mm² stranded. The ATEX Ex II (2) GD marking means it's approved for use in Zone 2 gas and Zone 22 dust atmospheres when paired with an appropriate contactor — relevant if the motor is in a classified area.