The 5SL6620-6CC: The B-curve (3–5× In magnetic trip) makes this MCB suited for resistive and general-purpose loads where inrush is moderate — lighting, small transformers, control circuits. The 6 kA breaking capacity at 400 V is the standard residential and light-commercial fault-interrupt rating in IEC 60898-1 applications; it safely clears a short-circuit fault up to that level without welding the contacts or cascading upstream. 3+N-pole means the breaker switches three phases plus a switched neutral — common in three-phase distribution boards where you want neutral isolation. The 20 A rating handles a 3-phase load up to roughly 13.8 kVA at 400 V line-to-line.
RoHS compliant since 01-06-13, with REACH candidate-list disclosure available on request. The product class is B — return restricted; contact your Siemens partner for RMA or technical support.