Chapter 2 Installation 11
Liebert ITA 16kVA/20kVA User Manual
The residual current circuit breaker (RCCB) must be sensitive to the DC unidirectional pulse (level A) in distribution
network, and insensitive to the transient current pulse, as shown in Figure 2-6 respectively.
Figure 2-6 RCCB symbols
When using the earth leakage current test device in bypass disconnection system or parallel system, the RCD should
be located at the upstream input distribution terminal to avoid generating the false alarm.
The earth leakage current introduced by the RFI filter in the UPS ranges from 3.5mA to 1000mA. It is recommended
to confirm the sensitivity of each differential device of the upstream input distribution and downstream distribution (to
load).
2.5.2 Battery Input
The over-current protective device has been placed into the battery module, when you choose the battery module
options provided by Emerson. Otherwise, the external battery cabinet should provide DC compatible circuit breaker,
so as to provide the over-current protection for the UPS and its batteries.
2.5.3 UPS Output
The protective device must be installed for the UPS output distribution. The protective device must be different from
the input distribution protection switches, and it also provides the overload protection (see Table 1-2).
2.6 Connecting Power Cables
I/O cables and battery cables are needed to be connected. Battery modules provide the battery cable options.
When designing the cables, you should follow the instructions in this section and the local wiring regulations, take the
environment situation into account, and refer to Table 3B of IEC60950-1.
Warning
1. Before carrying out the UPS wiring, ensure that you have learned about the location and status of the UPS input and mains
distribution switch. Make sure that the switches are in open state, and put up the warning mark to prevent the switches from
operating by others.
2. Failure to follow adequate earthing procedures can result in electromagnetic interference, electric shock hazard to personnel, or
the risk of fire.
2.6.1 Cables Selection
Select the cables according to Table 2-2.
Table 2-2 Maximum steady state AC and DC current
Rated current (A)
Mains input current
1
ǃ
2
when battery
charging with Max ability
Gross output current
2
at full load
UPS rated
power (kVA)
380V 400V 415V 380V 400V 415V
Battery discharging current upon
Min battery voltage
16 (3-in 3-out)
33
33
33
24
23
22
54
16 (3-in 1-out)
33
33
33
72
70
67
54
20 (3-in 3-out)
36
36
36
30
29
28
67
20 (3-in 1-out)
36
36
36
90
87
84
67
Note:
1. The mains input current of the rectifier and bypass.
2. Non-linear load (switch mode power supply) affects the neutral cable design of output and bypass. The neutral cable current
may exceed the rated phase current, in general, 1.732 times the rated current
