Liebert Emerson NX UPS System - Manual (Page 36)

UPS Multi-Module Installation
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Figure 15 Dry contacts, multiple UPS modules with distribution panel
3.2.2 External Protective Devices
Refer to the instructions in 1.0 - Single Module UPS Installation.
3.2.3 Power Cables
The wiring of power cables is similar to that of single module system. The Bypass and the Main input
sources must be referenced to the same neutral potential and input earth leakage monitoring devices,
if installed, must be located upstream of the common neutral sinking point. Refer to the instructions
in 1.0 - Single Module UPS Installation.
NOTE
The length and specification of power cables including the bypass input cables and UPS output
cables should be the same. This facilitates load sharing when operating in bypass mode.
Input Distribution
Distribution Panel
UPS 1 UPS 2
Q1Ext
To Load
Q2Ext QnExt
QByp
QUPS
UPS N
M3 Board
X3
Ext. Maint. Ext. Out
M3 Board
X3
Ext. Maint. Ext. Out
M3 Board
X3
Ext. Maint. Ext. Out
1 2 3 4 1 2 3 4 1 2 3 4