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3.3 Connection
3.3.1
I
NSTALLATION REQUIREMENTS
Warning:
Installation must be performed by qualified personnel. The first connection to perform is the protective conductor (earth
cable), which must be connected to the screw marketed
.
The UPS, when inserted in an installation, does not alter the existing neutral (system earthing) arrangements.
A differential switch upstream will also be triggered for a fault occurring downstream of the UPS. In calculating reactivity of this
switch, account must be taken of the leakage current of the UPS (approx. 8 mA) plus that of the load which come together on the
UPS’s earth conductor.
UPS input
Differential switch
Single-phase
Type B or Type A
Three-phase
Type B
The neutral arrangements are altered only if there is an isolating transformer or when the UPS operates with a neutral that is
disconnected upstream.
In any case avoid connecting the output neutral with the input neutral or to the earth as this could damage the UPS.
Reminder : The UPS needs a neutral connection to work properly. Operation without Neutral may damage the unit.
For installation with change in system earthing arrangement or galvanic isolation see below schematic
Fig.3-1 Change in SEA or Galvanic isolation
Notice:
It is required to install an external isolating device against current backfeed between Mains input and UPS. After the device
is installed, it must add a warning label with the following wording or the equivalent on the external AC contactor: RISK OF
VOLTAGE BACKFEED. Isolate the UPS before operating on this circuit, then check for hazardous voltage between all terminals.
The current rating of T - AC contactor should be more than 1.3 times of UPS capacity
Fig.3-2 Typical external isolating device installation
Single phase input
Three phase input
