What this MCB is and what the ratings mean for fit
The Siemens 5SY4616-7CC is a SENTRON miniature circuit breaker in a 4-pole (3P+N) configuration, meaning it switches three phases plus the neutral conductor — the neutral pole is switched, not just solidly linked. That matters when you need to isolate the neutral for maintenance or if local code demands it on a TN-S system. The C tripping characteristic means the magnetic trip operates at 5 to 10 times rated current, so it's sized for moderate inrush loads like small motor starters or transformer banks, not for pure resistive heaters (B curve) or high-inrush drives (D curve). At 35 °C ambient the continuous rating is the full 16 A; at 40 °C it derates to 15.04 A, at 50 °C to 14.02 A, and at 55 °C to 13.47 A. If your panel ambient runs above 40 °C, the effective ampacity is lower than the nameplate — size the upstream conductor accordingly. The breaking capacity is 10 kA per EN 60898, which certifies it for household and similar installations where the prospective short-circuit current at the point of installation does not exceed 10 kA. Overvoltage category III and pollution degree 3 confirm it's rated for fixed installation inside a distribution board or industrial control panel — not for plug-in portable use. Energy limitation class 3 means it limits let-through energy to a defined level under fault, which helps with downstream coordination.
Mounting and panel integration
The breaker occupies 4 modular width units on a DIN rail, with a quick-assembly fastening system — snap it on, no tools needed for the rail. Mounting position is any, so vertical or horizontal rail orientation is fine. The depth is 76 mm, width 72 mm, height 90 mm, and the installation depth behind the panel face is 70 mm. Combined terminals top and bottom accept both busbar and conductor connections; touch protection is built in. The IP20 rating is with connected conductors — standard for enclosed distribution boards, but not for wet or dust-exposed locations without an outer enclosure.
Environmental and compliance
Operating temperature range is -40 °C to 75 °C, which covers most outdoor cabinet and unheated warehouse installations. Humidity derating is specified: max 95% RH up to 55 °C, then 55% RH up to 70 °C, then 35% RH up to 75 °C — if your enclosure sees condensation at high ambient, the breaker's internal clearances are protected by pollution degree 3. The housing is halogen-free and silicon-free, which matters for outgassing-sensitive environments like data centers or clean manufacturing. Sealable means you can lock the toggle in the OFF position with a padlock hasp for lockout/tagout.