Njoy Ranger 30KR User Manual page 5

There can be no derivation in the line that goes from the «Backfeed
Protection» to the UPS, as the standard safety would be infringed.
Warning labels should be placed on all primary power switches installed
in places away from the unit to alert the electrical maintenance personnel
of the presence of a UPS in the circuit. The label will bear the following or
an equivalent text:
WARNING
Before working on this circuit!
- Isolate Uninterruptible Power Supply (UPS).
- Then check for Hazardous Voltage between all terminals
including the protected earth.
Risk of Voltage Backfeed!
1.5 Operation
Do not disconnect the grounding/earthing conductor cable on the UPS
or the building wiring terminals under any circumstance.
The UPS system features its own, internal current source (batteries).
The UPS output sockets or output terminal blocks may be electrically live
even if the UPS system is not connected to the building mains/live wires.
(only for standard models).
In order to fully disconnect the UPS system, first press the "OFF" button
and then disconnect the mains/live wires.
Ensure that no liquid or other foreign objects can enter into the UPS
system.
The UPS can be operated by any individuals with no previous
experience.
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