Siemens 5SL6420-7CC SENTRON MCB — 4-pole, C-curve, 20 A, 6 kA
The Siemens 5SL6420-7CC is a 4-pole miniature circuit breaker from the SENTRON series, rated 20 A with a C tripping characteristic and a 6 kA interrupting capacity per EN 60898 at 400 V AC.
The 4-pole configuration switches all three phases plus the neutral, so it fits three-phase sub-distribution or a three-phase load where neutral isolation is required. The C-curve characteristic avoids nuisance tripping on inrush from small transformers or capacitor banks while still protecting branch circuits. The DC rating tops out at 72 V — not a primary DC breaker, but usable for low-voltage DC auxiliary circuits within that limit.
The 4 MW width (72 mm) is standard for a 4-pole MCB — verify rail space if replacing a narrower 3-pole unit. Sealable per the spec, which matters for lockout/tagout procedures on a distribution board.
The closest functional peer in the SENTRON 5SL series is the 5SL4363-7 — a 3-pole, C-curve, 63 A unit with a higher 10 kA interrupting capacity per both EN 60898 and IEC 60947-2. The 5SL6420-7CC is 4-pole and 20 A, so it covers three-phase-plus-neutral circuits at a lower ampacity. The 5SL4363-7 occupies 3 MW (54 mm) versus 4 MW (72 mm) for the 4-pole. If your panel was specified for a 3-pole 5SL4363-7, the 5SL6420-7CC will not drop in without rewiring — different pole count, different current rating, and different width.