Always
O
n UPS Systems
M0703_NX_Series_Operators_Manual
V1.25
2012-06-12 23
6.6 Cable
Selection
The cabling of the UPS system has to be sized according to the UPS power rating.
Sizing of circuit breakers, fuses and cables for input utility, output load and battery must meet the
requirements of local and national electrical codes.
The following tables list the information between kVA of the UPS and the current requirements
of the systems.
WARNING
Inadequate cable size and over sized breakers can increase the risk of fire or damage
connection cables and internal components.
The following tables can be used to determine the input circuit breaker rating and the size of
cable for input, output and battery connections. This data is for reference only as final
installation must meet the requirements of local and national electrical codes.
6.6.1 CURRENT RATING FOR INPUT
Table 6.6.1.1
Maximum Input current ratings
KVA
Rating
Imax(A)
120/208VAC
3Ø
Minimum
Breaker/Fuse
Imax(A)
277/480VAC
3Ø
Minimum
Breaker/Fuse
Imax(A)
347/600VAC
3Ø
Minimum
Breaker/Fuse
10
45
50 20 20 16 20
15
63 70 27 30 22 30
20
83
90 36 40 30 30
30
125
125 55 60 45 50
40
160
175 70 70 56 60
50
200
200 90 90 70 70
60
250
250 110 110 90 90
80
330
350 145 150 115 125
100
415
450 180 200 145 150
120
500
500 220 225 175 175
160
660 700 290 300 230 250
When choosing a non-fused breaker (NFB) for the UPS, always choose the NFB that is
closest, but not below the maximum rated input current.
6.6.2 CABLE SIZE FOR INPUT & OUTPUT
NEC SECTION 210-20 (a)
Table 8.3.2 (next page) shows the allowable amperage of insulated conductors rated 0 through
2000 Volts, 60°C through 90°C (140°F through 194°F) not more than three current-carrying
conductors in a raceway, cable, or earth (directly buried), based on ambient temperature of 30°C
(86°F).