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3.4
Power cables connection
This chapter introduces how to wiring AC IN/OUT cable to UPS in difference mode, and
UPS connecting with EBM/MBP.
3.4.1 Input /Output wiring specifications
Before wring UPS, upstream breaker and backfeed contactor should be configured to
avoid power backfeed to the unit. And “backfeed voltage danger” warning label should
be added in backfeed contactor or device. Before operating, UPS input should cut off,
and check all terminals voltage to avoid voltage dangerous. Backfeed contactor rating
current should be larger than UPS rating input current.
Below figures show the wiring system of UPS input and output.
Single phase input system
Three phase input system
Danger!
The rated current of the utility power switch must be greater than the UPS input
current, otherwise the utility power switch may be burnt!
Recommended upstream protection and downstream switch:
UPS power rating
Upstream circuit breaker Backfeed contactor
Downstream switch
