
20
TR A N S FOR M E R BUS H I NG S T Y PE G S B 8 0 0
I N S TA L L AT I O N A N D M A I N T EN A N C E G U I D E
2.11 Flange grounding
The bushing flange is provided with a tapped M12 hole, see
Fig. 27. The bushing flange should be grounded to prevent
electrical discharges between bushing flange and
transformer/reactor during service.
Alternative 1
Insert a greased (Mobilgrease 28 recommended) pointed set
screw M12 (preferably stainless steel A4-80). Tighten to
40 Nm, penetrating the paint of the transformer/reactor
down to the metal beneath. This makes an electrical
connection between the bushing and the transformer/
reactor, keeping them at the same voltage.
Alternative 2
Connect a flexible cable between the M12 grounding hole in
the bushing flange and a corresponding connection point on
the transformer. Grease the screw (Mobilgrease 28
recommended) and tighten the M12 screw in the bushing to
40 Nm. Connect the other end of the cable to the
transformer.
—
27 Ground hole (M12).