Liebert Emerson NX UPS System - Manual (Page 38)

UPS Multi-Module Installation
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3.3.3 Power Cables
The wiring of power cables is similar to that of single module system except that the output of the
upstream UPS is fed into the bypass input of the downstream UPS, and the load is fed by the down-
stream UPS through its inverter or bypass. The bypass and the main input sources must be refer-
enced 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 Mod-
ule UPS Installation.
No control wires other than those specified for the single module configuration are required.
Figure 17 Hot standby configuration
INPUT DISTRIBUTION
TO LOAD
CB1
UPS1
OUTPUT
CB1
DOWNSTREAM UPSTREAM
RECTIFIER
STATIC
SWITCH
INVERTER
Mains L1,
L2, L3, N
L1, L2, L3, N L1, L2, L3, N
Bypass L1,
L2, L3, N Bypass L1,
L2, L3, N Mains L1,
L2, L3, N