Series 5ST3 Accessories Professional range of Siemens Sirius 5ST3 accessories. Accessories include a handle locking device, shunt trip releases and fault signalling switch mounts. Siemens Distribution Boards & Accessories Type B characteristic offers instantaneous short circuit response level of 3-5 x normal rated current, making it suitable for circuits with moderate inrush currents such as filament lamps, heating loads and most domestic/small building protection applications.,Type C characteristic offers short circuit response of 5-10 x normal rated current, making it ideal for circuits with higher inrush currents such as motor control and fluorescent lighting installations in industrial buildings where nuisance tripping might occur if a faster type was used.