2
1-4.
Connection Warnings
•
In accordance with safety standard, installation has to be provided with a
《
Backfeed Protection
》
system,
as for example a contactor, which will prevent the appearance of voltage or dangerous energy in the
input mains during a mains fault. There is no standard backfeed protection inside of the UPS. However,
there are relays on the Input to cut off line voltage and while the neutral is still connect to UPS.
Main
Input
Input Rly
UPS
L1
L2
L3
N
Main
Input
Input Rly
UPS
L1
L2
L3
N
Bypass
Input
Input Rly
L1
L2
L3
N
Input relay diagram
Input relay diagram for dual-input model
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:
•
The power input for this unit must be three-phase rated in accordance with the equipment nameplate. It
also must be suitably grounded.
•
This UPS should be connected with TN grounding/earthing system.
•
Use of this equipment in medical instrument of any life-sustaining equipment where failure of this
equipment can reasonably be expected to cause the failure of the life-sustaining equipment or to
significantly affect its safety or effectiveness is not recommended. Do not use this equipment in the
presence of a flammable mixture with air, oxygen or nitrous oxide.
•
Connect grounding terminal of UPS to a grounding electrode conductor.
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
WARNING
HIGH LEAKAGE CURRENT
EARTH CONNECTION ESSENTIAL
BEFORE CONNECTING SUPPLY
