Appendix G
Earth Bonding
Copyright © 2007-2013 Eaton Corporation. All Rights Reserved.
IPN 997-00012-49G May 2013
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Eart h Bonding
The earthing arrangement of your communications equipment determines how the dc common
bus of the dc power system is referenced to earth.
There are two options: ac and dc earths bonded, or ac and dc earths separated.
AC-DC Earth Linked (recommended)
During a lightning surge, very large voltages can develop between ac earth and dc common bus
as the surge current flows through the earth cables to earth.
Access Power Solutions dc power systems are factory fitted with an ac-dc earth link (see the
diagram on page
). This link prevents these very large voltages from developing and protects
the rectifiers from surge related damage.
If your installation uses a mesh earth, then Eaton recommends that this factory fitted ac-dc earth
link is retained. No further action is required.
However, if your policy is not to bond the ac/communications earth and dc earth (no mesh
earth), then refer to the following instructions to isolate the ac and dc earths.
AC and DC Earth Isolated
Perform the following steps to isolate the ac and dc earths, and (if required) install a transient
protective device.
Step 1 - Disconnect dc common bar from ac earth
1
Remove the screw securing the
busbar to the chassis.
2
Remove the bolt securing the
busbar to the dc common bar
and remove the busbar.
Busbar chassis screw
Busbar
Busbar nut
DC common bar
