Vertiv
| Liebert
®
NXL
™
500-750kVA UPS Installation Manual |
22
2.6.3 Preferred Grounding Configuration, Battery Systems
Open-rack battery systems, depending on local code requirements and customer preference, are
normally:
•
Floating (ungrounded)
OR
•
Center-tapped and floating
Battery cabinet systems must be connected as floating (ungrounded) systems.
Center-tapped or grounded battery systems are not possible with battery cabinet systems.
Whether the battery system is open-rack or cabinet, the metal rack parts or cabinet must be
grounded to the UPS module ground bus.
2.6.4 Multi-Module Systems
For both N+1 and 1+N systems, the neutrals of all UPS modules in the system must be connected
together inside the switchgear or parallel cabinet. The neutral conductors must be rated for 20%
of phase conductor current minimum. Site and load conditions will determine if larger neutrals are
required.
For multi-module systems using a 3-wire bypass, the Neutral-Ground bond must be made at the
common neutral connection point in the switchgear or parallel cabinet.
2.6.5 High Resistance Ground Systems
The Liebert
®
NXL
™
is compatible with high resistance ground systems. See your local Vertiv
™
representative for details.
2.7
Grounding Diagrams, Single- and Multi-Module Systems
Figure 11
Grounding diagram, three-wire single-module system
UPS
Source
G
N
BPSS
N
G
To c
o
n
nect
eq
ui
pm
en
t
