The Siemens 5SL3220-7MB is a 2-pole miniature circuit breaker from the SENTRON family, rated 20 A with a C-curve trip characteristic. It breaks fault currents up to 4.5 kA per EN 60898 at 400 V AC — the standard that governs overcurrent protection in residential and commercial final circuits. The 2-module-width (36 mm) body snaps onto a DIN rail and occupies 70 mm of enclosure depth, leaving room for gland plates and wiring ducts in a standard distribution board.
The 20 A C-curve rating means this breaker holds through moderate inrush — typical for lighting banks, small motor starters, and transformer primaries — and trips magnetically between 5× and 10× rated current. The 4.5 kA breaking capacity at 400 V AC is the maximum prospective fault current it can safely interrupt under EN 60898; for installations where the available fault current exceeds that, step up to the 10 kA variants in the same SENTRON family. The 2-pole design switches both phase and neutral on a single-phase 230 V circuit, or two phases on a 400 V line-to-line load.
The 36 mm width (2 modular units) and 76 mm depth fit standard consumer units and sub-distribution boards. Sealable design allows lockout-tagout provisions.