The Siemens 5SL4520-7CC is a 1+N-pole miniature circuit breaker rated 20 A with a C-trip curve, breaking capacity of 10 kA at 230 V. It's a current-production Basic Devices family part — still rolling off the line, not a phase-out or NRND item. That C-curve means it handles moderate inrush from motor starters and lighting ballasts without nuisance tripping, while still clearing hard faults inside the 10 kA interrupt rating. The 1+N configuration switches both line and neutral, which matters when you need full isolation downstream.
Snap-on DIN rail mount, standard 1+N module width. Pairs with the 5SL series busbar and accessory range. The 10 kA interrupting capacity at 230 V gives you enough fault-clearing headroom for most residential and light commercial distribution boards — just verify the prospective short-circuit current at the point of installation doesn't exceed that. Group code P310, product group 3823 if you're cross-referencing Siemens internal catalogs.