Vertiv
™
|
Liebert
®
NX
™
225-600kVA Installation Manual | Rev. 8 | 07/2017
19
2.5.3
High-Resistance Ground Systems
Liebert NX 400-600kVA units produced on or after August 1, 2013, with serial numbers as indicated below, are
compatible with High Resistance Ground (HRG) applications. Earlier production units may NOT be compatible
with HRG application and may either bear no label or be specifically labeled as not compatible. If the Liebert NX
UPS is NOT labeled as either compatible or not compatible, contact the factory before installing the unit in an
HRG application.
Liebert NX Serial Numbers/Compatibility with High Resistance Ground
NX 225-600 kVA serial numbers are structured as follows:
(Digits 12, 13 and 14 are underlined above)
Digits 12 and 13
of the serial number represent the year of production
Example—
1 3
= calendar year 2013;
1 4
would represent calendar year 2014.
Digits 1
and
3
represent the month
Example—
1-9
= January-September, A = October, B = November, C = December
(e.g.
1 38
= August 2013, 1 3C= December 2013)
HRG compatibility was instituted for Liebert NX 400-600kVA units effective August 1, 2013, so serial numbers
with Digits 12,13 and 14 of
1 38
or higher designate Liebert NX 400-600kVA units that have HRG compatibility.
Contact the factory for HRG compatibility for Liebert NX 225-300kVA units.
2.6
D
ISTRIBUTED
S
TATIC
S
WITCH
(1+N) S
YSTEM
C
ABLING
L
AYOUTS
The output switchboard for a 1+N system must be configured with one Module Output Circuit Breaker (MOB) for
each UPS module to be connected to that switchboard. The breaker must be equipped with auxiliary contacts
that will be monitored by the UPS so that interlocks will function properly and for the HMI to indicate the
bypassed status of the module. Vertiv recommends using magnetic or thermomagnetic breakers. If molded case
switches will be used, Vertiv recommends installing breakers without electronic trip units or to set the trip units
as follows:
•
For 225-300kVA Modules
: 2000A for 2 milliseconds
•
For 400-600kVA Modules
: 3000A for 2 milliseconds.
21
XXXXXXXX
1 38
X XX XXXX
