Liebert 600TTM - Manual (Page 23)

Configuring Your Neutral and Ground Connections 17
7.3 Preferred Grounding Configuration with Power-Tie Switchgear
Figure 5 Preferred Grounding Configuration, Power-Tie Systems
Multi-Module Systems can be used with Power-Tie switchgear to provide dual critical load busses.
The Power-Tie switchgear permits transferring critical loads from one critical bus to the other so
that one UPS system and associated breakers can be de-energized for maintenance. Certain con-
figurations of Power-Tie equipment also permit the operator to continuously parallel the output of
both UPS systems.
In tied systems, each SCC must have its neutral solidly connected to the Power-Tie switchgear
neutral. The UPS modules, as usual, must have their output neutrals solidly connected to their
respective SCC neutrals. There should not be a connection between the service entrance neutral
and either the SCC or module neutrals.
NOTE
It is essential to run a neutral connection between the tie switchgear and
both SCCs as shown in the illustration above.