Access Power Solutions Installation and Operation Guide (APS6-300/500 and APS12-300 Series)
92
Copyright © 2007-2013 Eaton Corporation. All Rights Reserved.
IPN 997-00012-49G May 2013
Step 2 - Remove or replace the ac-dc Earth Link
Ignore this Step if the factory fitted ac-dc earth link is used.
There are two options if the ac-dc earth link cannot be retained. Either:
If the site surge protection is designed to limit transient ac earth - dc earth
voltages to less than 1500V at the dc power system, then remove the ac-dc earth
link as in Step 1. No further action is required.
APS chassis
AC earth link
AC earth / communications earth
DC common bus
Customer dc earth
Cabinet bond
Or, if the site surge protection is not designed to limit transient ac earth - dc
earth voltages to less than 1500V at the dc power system, then replace the ac-dc
earth link with a surge protection device.
The surge protection device bonds the ac and dc earths during transient activity
to prevent damage to the rectifiers. The preferred surge protection device is a
transient earth clamp (TEC).
APS chassis
AC earth link
AC earth / communications earth
DC common bus
Customer dc earth
Cabinet bond
Transient earth clamp surge protection device
The path between ac earth and dc common bus (via the surge protection device) must
be as short and straight as possible, preferably less than 500mm (20").
The transient earth clamp must have the following minimum specifications.
Nom. dc Spark-over Voltage
600V
Impulse Spark-over Voltage at 1 kV/μs
< 1400V
Nom. Impulse Discharge Current – 8/20μs wave shape
20kA
Insulation Resistance at 100V
10
10
Capacitance
< 1.5pF
A larger transient earth clamp with a high kA rating must be used if the potential
severity of a lightning strike is high.
Procedure complete
