Battery Input (For External Battery); Connecting Power Cables - Liebert NXC User Manual

Liebert NXC
1. The same neutral line must be used for the rectifier and bypass power.
2. For IT power grid system, the quadrupole protective device must be installed at the UPS external I/O power distribution.
Earth leakage current
The residual current detector (RCD) for the UPS upstream input power distribution should be:
 Sensitive to the DC unidirectional pulse (level A) in power distribution network
 Insensitive to the transient current pulse
 General sensitivity type, settable: 0.3A ~ 1A
The residual current circuit breaker (RCCB) must be sensitive to the DC unidirectional pulse (level A) in power distribution
network, but insensitive to the transient current pulse, as shown in Figure 2-2 respectively.
When using the earth RCD in split-bypass system or parallel system, the RCD should be located at the upstream input power
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 power distribution and downstream power distribution (to
load).

2.3.2 Battery Input (for external Battery)

The overcurrent protective device has been placed into the battery cabinet, when you choose the battery cabinet option
provided by Emerson. Otherwise, the external battery cabinet should provide DC compatible fused circuit breaker, so as to
provide the overcurrent protection for the UPS and its batteries.

2.4 Connecting Power Cables

I/O cables and battery cables are required for connection. When connecting the cables, you should follow the local wiring
regulations, take the environment situation into account, and refer to Table 3B of IEC/EN 60950-1. The max. current in different
operating modes is listed in Table 2-2, the recommended min. cable CSA is listed in Table 2-3. Select the appropriate cables
according to Table 2-2 and Table 2-3.
User Manual 10H52188UM51 - Rev. 1 - 09/2011
Single UPS Installation and Commissioning
Note
Figure 2-2 RCCB symbols
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