ABB PP882 Hardware And Installation Manual page 34

Grounding the operator panel
2.
3.
4.
A ferrite core suppresses disturbances to the 24 V feed, see 6 in drawing above.
The grounding wires should be short and the conductor should have a large area.
A long, thin grounding wire has a very high impedance (resistance) at high
frequencies and does not guide disturbances to the ground.
Multi-wire conductors are better than single wire conductors with the same area.
A braided conductor wire with the same area is even better. The best is a short,
thick grounding braid.
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Connect a wire or grounding braid, that is sized correctly according to local
electrical codes, between the chassis of the operator panel and the closest
grounding point on the door, see 3 in drawing above.
Connect a strong but short grounding braid between the door and the device
cabinet, see 4 in drawing above.
Twist the cables onto the 24 V DC feed, see 5 in drawing above.
2 turns around the ferrite core provide 4 times the suppression of 1 turn.
3 turns around the ferrite core provide 9 times the suppression of 1 turn.
Section 7 Additional Installation Tips
3BSE069462-600 Rev D