What it is and what it does
The Siemens 5SM2632-6 is a SENTRON RCD-unit — a residual-current device designed as a companion for the 5SY miniature circuit breaker line. It is a 3-pole, Type A, instantaneous-trip device rated 40 A with a 300 mA fault-current sensitivity, for 400 V AC 50 Hz systems. Type A means it detects sinusoidal AC faults plus pulsating DC faults up to 6 mA smooth DC, which covers most modern electronics and VFD-fed loads. The instantaneous design means no intentional time delay — it trips within a cycle on a ground fault, which is what you want for personnel protection but not for feeder selectivity.
Ratings that matter for fit
The 5SM2632-6 occupies 3 modular-width units (3 MW, 17.5 mm each) on a DIN rail — that is 52.5 mm of rail space, plus it needs the connected MCB alongside. At 107 mm wide overall, it is a wide-body RCD; the 70 mm depth and 90 mm height match the standard SENTRON MCB profile, so it sits flush in a populated distribution board. Insulation voltage (Ui) is rated 460 V, with a 4 kV surge voltage withstand — Overvoltage Category III, so it is rated for fixed-installation distribution panels, not just sub-distribution. Pollution degree 2 (non-conductive pollution that becomes conductive only when condensation occurs) is the standard for enclosed distribution boards.
Where it goes and how it mounts
This RCD snaps onto a DIN rail (REG fastening method) and can be mounted in any position. IP20 with connected conductors.