Emerson Liebert NX 50 and 60 Hz - Manual (Page 59)

UPS Multi-Module Installation
47
Figure 30 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
UPS 1
M3 Board
X3
Ext. Maint. Ext. Out
UPS 2
M3 Board
X3
Ext. Maint. Ext. Out
UPS N
M3 Board
X3
Ext. Maint. Ext. Out
To Load
QUPS
QByp
Q1Ext Q2Ext QnExt