The Siemens 5SU1353-0KV25 is a combination residual-current device and miniature circuit breaker (RCBO) in a single 1+N-pole module. It integrates Type AC residual-current protection at 30 mA sensitivity with a B-curve overcurrent trip set at 25 A, all rated for a 4.5 kA short-circuit capacity. The 70 mm depth fits standard Siemens distribution boards and consumer units.
What the ratings mean for fit
The 30 mA residual sensitivity (IΔn) is the standard threshold for personnel protection against direct contact in TN and TT systems — it clears a ground fault before the let-through energy reaches a dangerous level. The B-curve (3–5 In) means the magnetic trip operates between 75 A and 125 A, suited for resistive or lightly inductive loads like lighting, socket outlets, and small control transformers. The 4.5 kA breaking capacity (Icn) covers domestic and light commercial installations where the prospective short-circuit current at the point of installation stays below that level; for industrial panels with higher fault capacity, a higher-rated upstream device would be needed.
Integration note
The 1+N-pole format occupies a single modular width on a DIN rail, with the neutral switched and protected. The 70 mm depth is consistent with Siemens 5SU1 series RCBOs, so it aligns with standard enclosure gland-plate clearances. Wire termination follows the terminal markings on the housing; no special tooling beyond a standard screwdriver is required.