The Siemens 5SU9307-7QS32 is a Crabtree Polestar RCBO — a combined residual-current circuit breaker with overcurrent protection — rated for 16 kA breaking capacity, Type A (pulsating DC and AC sensitive), 30 mA earth leakage trip, C32 characteristic (32 A, C-curve for moderate inrush), with Long Tail terminals for easier wiring in distribution boards.
What the ratings mean for fit
The 16 kA breaking capacity at 230/400 V means this RCBO can safely interrupt a short-circuit fault up to 16 kA without welding its contacts or cascading damage upstream — it's sized for domestic or light commercial distribution boards where the prospective short-circuit current (PSCC) is known to stay under 16 kA. The C32 curve (32 A nominal, C characteristic) trips between 5× and 10× In (160–320 A magnetic trip), so it handles motor inrush or capacitive loads without nuisance tripping, but clears fast on a hard short. Type A residual-current sensitivity (30 mA) detects sinusoidal AC faults plus pulsating DC up to 6 mA — essential for circuits with single-phase rectified loads like washing machines, LED drivers, or EV chargers that can blind a standard AC-only RCD. The 30 mA threshold provides personal protection against direct contact.
Where it's used
This RCBO snaps onto a standard DIN rail inside a consumer unit or sub-distribution board — the Long Tail terminals simplify the final wiring step, giving the panel builder extra length to land the outgoing circuit cable without stretching the busbar connection.