Installation guide

Safety
72
890USE17100 September 2003
The Protective Earth Connection
PE Contact for
the Island
One of the key functions of a PDM, in addition to distributing sensor and actuator
power to the I/O modules, is the provision of protective earth (PE) to the island. On
the bottom of each STB XBA 2200 PDM base is a captive screw in a plastic block.
By tightening this captive screw, you can make a PE contact with the island bus.
Every PDM base on the island bus should make PE contact.
How PE Contact
Is Made
PE is brought to the island by a heavy-duty cross-sectional wire, usually a copper
braided cable, 4.2 mm
2
(10 gage) or larger. The wire needs to be tied to a single
grounding point. The ground conductor connects to the bottom of the each PDM
base and is secured by the PE captive screw.
Local electrical codes take precedence over our PE wiring recommendations.
Handling
Multiple PE
Connections
It is possible that more than one PDM will be used on an island. Each PDM base on
the island will receive a ground conductor and distribute PE as described above.
This illustration shows separate PE connections tied to a single PE ground:
1 the NIM
2 a PDM
3 another PDM
4 captive screws for the PE connections
5 FE connection on the DIN rail
Note: Tie the PE lines from more than one PDM to a single PE ground point in a
star configuration. This will minimize ground loops and excessive current from
being created in PE lines.
PE
PE
1 2
3
4
5