What this part is and where it fits
The Siemens 5SU1356-0DV16 is a combined residual-current device and miniature circuit breaker (RCBO) — one unit does both the earth-leakage protection and the overcurrent/short-circuit protection. It is a Type AC device, meaning it detects sinusoidal AC residual currents only; for pulsating DC or mixed-frequency faults you would need a Type A or Type F unit. The 30 mA trip sensitivity is the standard for personal protection against direct contact in residential and commercial final circuits. The B-curve 16 A rating trips instantaneously between 3 and 5 times rated current (48–80 A), which is the usual choice for resistive and general-purpose loads with modest inrush — lighting, socket outlets, small appliances. The 6 kA breaking capacity (Icn) covers the fault level typical of domestic and light commercial distribution boards; if your service entrance has a higher prospective short-circuit current, you would need a unit with a higher Icn or a backup fuse. The 1+N-pole construction switches and protects the phase only; the neutral is switched but not protected. The 70 mm width (about 4 module spaces) and pig-tail connection are the standard form factor for DIN-rail mounting in a consumer unit or sub-distribution board.
What the ratings mean for your panel
The 70 mm width (DIN-rail footprint) occupies four 17.5 mm module spaces in a distribution board or enclosure. The pig-tail connection is the factory-fitted neutral tail that connects to the neutral busbar — no separate neutral link to buy. For a panel builder or wireman, the key fit check is the busbar pitch and the neutral bar position; the pig-tail length is standard for domestic consumer units. The 6 kA breaking capacity is the Icn per EN 60898-1, which is the standard for miniature circuit breakers in household and similar installations. If your installation requires a higher Icn (e.g., 10 kA per IEC 60947-2 for industrial panels), this unit is not the right choice — you would step up to the Siemens 5SU1 series with a higher interrupting rating.
Deployment context
This RCBO is designed for DIN-rail mounting in a distribution board or consumer unit — typical deployment is in residential, commercial, or light industrial final circuits where both earth-leakage and overcurrent protection are required in a single module. The Type AC classification means it is suited for circuits with sinusoidal AC residual currents (standard lighting, socket outlets, general appliances). It is not suitable for circuits with electronic loads that generate pulsating DC residual currents (e.g., washing machines, LED drivers, EV chargers) — those require a Type A or Type F device.