22
R (l)
n
U (l)
n
(1)
(3)
(2)
SAi
«backfeed protection» connection for KESSUPS 91RT > 3 kVA with
static bypass line (no Jumper).
«backfeed protection» connection for KESSUPS 91RT> 3 kVA with no
static bypass line (Jumper fitted in).
(3)
(2)
(1)
SAi
in
pu
t
o
ut
put
o
ut
put
in
pu
t
by
pass
(1) Automatic «backfeed protection» protection system, external to the UPS (En-iEC 62040-1).
(2) Fuse holder and fuse for general purpose of 250V AC / 3A type F.
(3) Two poles contactor of 230V AC with a minimum distance between contact of 1,4 mm and coil of the same voltage, with the minimum current stated in the
nameplate of the UPS (input or bypass according to).
R (l)
n
R (l)
n
U (l)
n
R (l)
n
JP
Cable as bridge
mode "Jumper"
factory installed
Fig. 12. wiring diagram for “backfeed protection”.
• in accordance with safety standard En-iEC 62040-1, the installa-
tion has to be provided with a «backfeed protection» system, as
for example a contactor, which will prevent the appearance of
voltage or dangerous energy at the bypass line during a mains
fault (see figure 12 and respect the circuit diagram of the par-
ticular «backfeed protection» for the equipment with bypass line.
There can be no derivation in the line that goes from the
«backfeed protection» to the UPS, as the safety standard
would be infringed.
• warning labels should be placed on all primary power switches
installed in places away from the device to alert the electrical
maintenance personnel of the presence of a UPS in the circuit.
The label will have the following text or an equivalent one:
before working on this circuit.
• isolate Uninterruptible Power System (UPS).
• Then check for Hazardous Voltage between all terminals
including the protective earth.
Risk of Voltage backfeed from UPS.
• Connect the power supply cables to input power blocks R (l), and
n, by respecting the phase and neutral rotation stated in the la-
belling of the equipment and in this manual (see figure 13). if this
rotation is not respected, serious faults could happen.
when discrepancies exist between the labelling and the instruc-
tions of this manual, the labelling will always prevail.
•
in parallel systems, the length and cross section of the ca-
bles that go from the switchgear panel till one of the UPSs
and vice versa, will be the same for all of them without any excep-
tion.