16
6.5.3 Connection torque
Bolts shall be secured with a torque wrench to ensure uniform clamping force. To eliminate any restoration after
fastening at the contact areas, it is recommended that the fastening bolts be re-checked after several weeks. However,
the torque shall not be higher than the torque used in the first installation. It is recommended that the bolts be
tightened according to the torque values listed in the table below.
Torque values for busbar connections and tap connections
Bolt
Torque (Nm)
(Ungreased)
M6
10
M8
20
M10
45
M12
75
M16
140
6.6 Electrical safety clearance
Sufficient space must be ensured around the transformer to ensure a smooth connection of the cable and the necessary
electrical distance. Minimum clearance value for flashover protection is as bellow.
Figure 4 The high voltage side is the minimum
c l e a r a n c e a r o u n d t h e c a s t r e s i n
transformer connected to the junction
box (1)
Figure 5 The high voltage side is the minimum
c l e a r a n c e a r o u n d t h e c a s t r e s i n
transformer connected to the copper
tube (2)
6. Installation