Installation and maintenance instructions UniGear type ZS2 UniSafe-36 1YTW571780-012 Rev:E 01-2005 en Page: 11 of 25
2.5 Busbar assembly
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CAUTION! The encapsulating sheet steel of cubicles may have sharp edges inside and on the roof.
Access possibilities for the main busbars installation are shown on the below figure, they are:
-side access during installing the adjacent cubicle
-removable roof plate
-removable rear cover + rear plate of the main busbar compartment
It is advisable that the busbar erection is done in parallel with the cubicles erection when access to the main
busbar compartment is available from side.
The insulated main busbars, and tee-boots are delivered loose in each respective panel,
Fastening parts are delivered ready-fixed on the dropper busbars.
Busbar assembly work require cleanness as the dielectric strength will be decreased by metal dust etc.
Fig:2.5.1 Access for main busbars installation
The insulated busbars must be protected against damaging of the insulation. Damaged insulation must be
renewed. The PVC protective with air cushion will protect the insulated parts from damages also during
transport and installation period. Keep them on the busbars as long as possible until commisioning. Busbar
assembly work require cleanness as the dielectric strength will be decreased by metal dust etc.
Fig:2.5.2
Fig:2.5.3
Make sure the contact surfaces of busbars and connector parts are clean. Use only the strong type of conical
spring-washers (ABB 9ADA334, DIN 6796) for all bolted conductor connections. This will keep the
required pressure for the lifetime of the switchgear eliminate the risk of problems due to overheating.
Torque-meter should be used during erection , tightening torque are as tabulated in chapt:2.8
Note for 1250A main busbar assembly, dropper busbars delivered until mid-2004 had M16 thread in copper,
in this case the engaged length of bolt-thread is critical to be maximum not to damage the copper thread,
also reduced torque (90Nm) with greasing of bolt head should be applied. Greased bolt due to low friction
assure equivalent contact pressure with less tightening torque.
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