What it is and what it does
The Siemens 5SL4425-7RC is a SENTRON miniature circuit breaker (MCB) with four poles, a C tripping characteristic, and a 25 A rated current at 415 V AC. Its 10 kA breaking capacity per EN 60898 means it can safely interrupt a fault current up to 10,000 A without welding its contacts or damaging downstream equipment — that's the standard for residential and light commercial distribution boards in most IEC markets.
What the ratings mean for your panel
The C-curve trips between 5 and 10 times rated current, so it's the right choice for inductive loads like small motors, transformers, and fluorescent lighting banks where the inrush won't nuisance-trip a B-curve but you don't need the D-curve's higher magnetic threshold. Rated 25 A at both 30 °C and 40 °C ambient, so no derating headache in a warm enclosure. The 4-pole design switches all three phases plus neutral, but note the neutral is not switched — it's a solid-through neutral pole, which is standard for TN-S systems where you want overcurrent protection on the line conductors only. Maximum operating voltage is 440 V AC in multi-phase operation, and 250 V AC single-phase. That 440 V ceiling covers most 400/415 V three-phase networks with headroom for nominal variations. The DC rating tops out at 72 V, so this isn't your DC string combiner box breaker — keep it on AC circuits.
Panel fit and mounting
Snaps onto standard 35 mm DIN rail. At 18 mm width it takes up exactly one modular unit, so four of these side by side eat 72 mm of rail — plan your enclosure layout accordingly. Depth is 76 mm, installation depth 70 mm, so it clears a standard 80 mm deep enclosure with a few mm to spare for wiring. IP20 with connected conductors means it's protected against finger contact but not water — keep it inside the panel, not on the machine frame. Mounting position is any, so you can run the DIN rail vertically if the cabinet layout demands it.