Planning with SIVACON 8 PS - Siemens

Planning with LDA/LDC4.2 System components4.2.11 Tap-off unitsTap-off for different current ratingsTap-offs for different current ratings are required, depending on the application and type andsize of loads. These tap-offs are implemented in the form of tap-off units with fuseswitch-disconnectors or with circuit-breakers.Features of Siemens tap-off units:● Plug-in tap-off units can be fitted/removed easily● Are designed with a steel enclosureThere are basically two types of tap-off unit:● With fuse switch disconnector● With circuit-breakerFigure 4-9Tap-off unitEarly-make PE/PENThe current tap in the tap-off unit is implemented as an early-make (mounting) or late-break(removal) PE/PEN conductor contact.In a 4-conductor system, this is ensured by a longer PEN bar at the contact mechanism. In a5-conductor system the PE connection is established via grinding contacts on the codingbrackets.Anti-rotation feature and non-interchangeabilityThe coding brackets on the tap-off unit and on the trunking unit's tap-off point (lock-and-keyprinciple) ensure:● Non-interchangeability and correct assignment of 4 or 5-pole tap-off units to theassociated LD systems● Orientation feature to prevent incorrect connections between the tap-off units and tap-offpointsPlanning with SIVACON 8 PSPlanning Manual, 10/2007, A5E01541101-01 121