Chapter 3 Electrical Installation 19
NX UPS Single Module And Parallel System 250kVA ~ 800kVA User Manual
rapid fuse in the main power cabinet needs 8ms to 10ms, therefore, it is required that the user’s upstream protective
device do not act in 10ms to coordinate with the protective device in the main power cabinet to cut off the fault and
transfer the UPS to the bypass. In split bypass configuration, separate protective devices should be installed for the
rectifier input and bypass input in the incoming mains distribution panel.
Note
1. The rectifier input and bypass input must use the same neutral line.
2. The UPS output neutral relies on input neutral. External upstream disconnect devices opening input neutral may cause loss of
output neutral reference and hazards.
2. Earth leakage
The residual earth current introduced by the RFI suppression filter inside the UPS is greater than 3.5mA and less
than 5000mA. It is recommended to verify the sensitivity of all differential devices upstream of the input distribution
panel.
External BCB
The UPS provides a BCB box as a mandatory part to provide overcurrent protection, short circuit protection and
automatic tripping functions for the external battery. The rated voltage of the BCB is 500Vdc, and its DC breaking
current is 20kA.
UPS
output
The UPS output distribution shall be configured with a protective device. The protective device shall be different from
the input distribution protection switch and able to provide overload protection (refer to Table 11-6).
3.1.8 Power Cable Connection Procedures
Important
The operations described in this section must be performed by authorised personnel. If you have any questions, please contact
the local customer service center of Emerson immediately.
Connection terminal and cable routing method
Figure 3-1 and Figure 3-3 show the UPS power cable connection terminals. Figure 3-4 ~ Figure 3-8 show the power
cable entry and routing methods.
Warning
1. The power cables should be routed through metal tunnels or metal cable troughs to prevent cable damage due to mechanical
stress and reduce the electromagnetic interference to the environment.
2. When routing the cables inside the cabinets, it is required to bind and fix the cables as instructed in Figure 3-4 ~ Figure 3-8 in
the cabinets to prevent cable damage due to mechanical stress.
