3.4 PARALLEL OPERATION (ONLY FOR 8/10 KVA)
The paralleling cable delivered with each UPS allows you to connect up to 3 UPS together in a parallel
system.
NOTE
The units connected in parallel must be the same power rating (i.e
. 8 kVA-8 kVA not
8 kVA-10 kVA) and must have the same output voltage setting (i.e. 120V-120V not 120V-
127V). Before starting up a parallel system be sure that the output terminals on all UPS
are connected in the same way (see section 3.3.9, fig. 3.3.9.d).
3.4.1 Installation of a parallel system
1. All inputs of the UPS must be supplied from the same phase. Be sure that L1 / L2 / N correspond on all
the units of the parallel system. All inputs have to be protected individually by fuses. The values of
these fuses should correspond to the values mentioned in section 3.2.
2. All outputs must be connected together, supplying the load. It is advised to install switches (S 1, 2, 3
fig 3.4.1) in the output wiring, in order to be able to isolate a unit from the remaining system for
service and maintenance purposes.
3. Use insulated copper input and output wiring, rated 90°C (194°F) wire size based on the ampere
capacities given in Tables 310-16 of the National Electrical code, ANSI/NFPA 70-2008.
4. The length of all input cables from the input junction (Li, fig. 3.4.1) to the UPS inputs should be equal.
The same applies to the cables from the outputs to the output junction (Lo, fig. 3.4.1). The minimum
length of the input as well as the output cables is 3 meters.
5. The overall system load may not exceed 100% load of a single UPS in the configuration without the
addition of an external maintenance bypass.
fig. 3.4.1
modifications reserved
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User manual GT Series 5/6/8/10 kVA UPS 1.0 (US)