ABB UniSec Manual

Also see for UniSec: Operation and maintenance manual Operation and maintenance manual

Contents

ABB UniSec Manual Manual pdf 37 page image

375.2 Control cablesThe internal cables between units are easily laid through open-ings in the side walls of the auxiliary circuit compartment.Depending on the delivery times, there are two different proce-dures for supplying the connection cables of the units:• Cables not included• Cables supplied rolled in a bundle in the auxiliary circuitcompartment.Table 6 gives the correct torques for the terminal blocks.Terminal BlocksWidth of terminalbox (mm)Cross-Section ofcable (mm 2 )Tightening Torque(Nm)5 0.2-2.5 0.4-0.66 0.2-4 0.5-0.88 0.5-6 0.8-1Table 6. Terminal BlocksThe options available for control cable entry are:• Side duct at both ends of the switchgear.• A duct can also be placed on the roof of the switchgear tosupport the incoming cables, for example, from an overheadcable ladder.Figure 124. Control cable entries5.3 Earthing the switchgearEach unit is fitted with earthing busbars that run longitudinallyin the lower front part of the unit. These busbars must beconnected together as shown in chapter 5.3.1. The stationearthing system must be connected to the end unit of theswitchgear. If the switchgear consists of more than 8 units, itis advisable to connect the station earthing system to both endunits. The external station earthing connection point inside theunit is shown in Figure 128. All the apparatus is connected to theearthing busbar via the switchgear housing. The interconnectionbetween units is capable of carrying the rated short-time andpeak withstand current for the earthing circuit.5.3.1 Installing the earthing busbarInstallation operations are as follows:a) Unscrew the right-hand screw (when there is another unit onthe right side) and loosen another two screws. Then movethe busbar towards the adjacent unit on the left.Figure 125. Busbar moved towards the adjacent unit on the leftb) Move the busbar from the unit to the right (when there isanother unit on the right). Add the screw on the right andscrew up all the screws with the correct torque.Figure 126. Busbar moved from the adjacent unit to the right