General Information
The maximum cable length for the device input and output connection should not exceed 7 meters
and for the connection between the UPS and the battery bank should not exceed 5 meters.
Table 2.7: Maximum gauges for input and output phases terminals of three-phase equipment
ATTENTION!
If longer lengths than recommended to connect the input, output or batteries
to the UPS are required, a switch board panel should be provided considering
the voltage drop across the conductors.
2.11.1 Backfeed Protection Circuit
If necessary, an anti-backfeed system can be used on the UPS Distribution Board as shown
in the diagram below.
A: Circuit Breaker or Main Switch of the Power Line.
C: Circuit breaker or fuses for the Mains Line.
B: Circuit breaker or fuses for the Reserve Line.
K3: Contactor for voltage backfeed protection.
K1-K2: Auxiliary relays in the supply circuit of the contactor coil.
A
R
S
T
N
Distribution Board
15 | Enterprise
UPS Power
Voltage (Vac)
(kVA)
10
15
20
380
25
30
40
10
220
15
20
B
K1
C
Figure 2.6: Backfeed protection circuit
Maximum Cable
Gauge (mm²)
10
10
10
10
10
16
10
10
16
K3
K2
UPS
R RESERVE
S RESERVE
T RESERVE
N
R MAINS
S MAINS
T MAINS
N