What it is and where it fits
The Siemens 5SU9304-1KK06 is a 2-pole RCBO (RCD-operated circuit breaker) from the SENTRON family, combining overcurrent and residual current protection in one 18 mm wide module. Rated 6 A with a C tripping characteristic and 30 mA residual current sensitivity, it is designed for final circuits in residential or commercial distribution boards where both short-circuit and earth-fault protection are required in a single device. The 10 kA breaking capacity per EN 60898 covers typical domestic and light commercial fault levels. It is halogen-free and silicon-free, which matters for panels in clean-room or corrosive environments where outgassing is a concern.
Ratings and what they mean for fit
The 6 A rating at 30 °C is the nominal current; at 40 °C it derates to 5.64 A, at 50 °C to 5.22 A, and at 55 °C to 4.86 A. If your panel ambient runs above 30 °C, size the upstream breaker accordingly — the C-curve means magnetic trip occurs at 5 to 10 times rated current, so it handles motor inrush on small pumps or compressors without nuisance tripping. The 30 mA residual current trip is standard for personal protection against direct contact. Insulation voltage is rated 264 V, surge voltage resistance 4 kV, overvoltage category III — suitable for fixed-installation mains distribution. The 18 mm width (1 modular unit) saves rail space compared to a separate MCB+RCCD pair.
Mounting and integration
Snap-on DIN rail mount, any position. Installation depth is 70 mm, overall depth 77 mm — check gland plate clearance if your enclosure is shallow. IP20 with distribution board installed and conductors connected; not rated for wet or dusty environments without an outer enclosure. Supply can enter from top or bottom. Touch protection is provided on the terminals.