The Siemens 5SL6420-8CC is a 4-pole miniature circuit breaker (MCB) rated 400 V with a 6 kA breaking capacity, a D-trip curve, and a 20 A current rating — a standard DIN-rail mount device for protecting branch circuits in commercial and light industrial panels. The D-curve means it trips magnetically between 10 and 20 times rated current (200–400 A for this 20 A unit), making it the right choice for loads with high inrush like small motors, transformers, or solenoid banks — not for general lighting or resistive loads where a B or C curve would do.
RoHS compliance is confirmed since June 2013, and REACH candidate-list information is available on request — both matter if your quality or compliance team needs documentation for the file. The product class is B: return restricted.
Leave a finger's gap above and below for the arc-chamber venting — don't bury it against the gland plate or a solid cable duct. Rated for 400 V line-to-line, so it covers 3-phase 4-wire systems (three phases plus neutral) up to 400/230 V or 400/277 V configurations. The D-curve handles the inrush of a 5–7.5 kW motor starter or a small control transformer on the same branch.