page 15 / 84
0MLMHTM30RUENUA
5
Electrical Connections
A
CCESSING THE
UPS
TERMINALS
The following operations must be performed while the UPS is disconnected from
the utility mains power, switched off and all the input and output power switches
on the equipment are open. Before performing connection, open all the input and
output power switches and check that the UPS is completely isolated from all
power sources: battery and AC power line. In particular, check that:
- the UPS input line is completely isolated;
- that the battery circuit breaker/disconnect is open;
- all the UPS power and load connection switches (SWIN, SWBY, SWOUT
and SWMB if fitted) are in the open position;
- no dangerous voltages are present (use a multimeter).
The first connection to be performed is the protective wire (earth ground cable)
which has to be inserted into the terminal labelled “Grounding Electrode Terminal”.
The UPS must operate with the grounding system connected.
Do not connect the output neutral to the input neutral.
CAUTION: If the input connection is Delta the UPS can supply only Delta load.
The output neutral must not be connected unless the UPS is the Wye version
supplied with an input neutral.
TRANSFORMER BOXES (optional) are available for converting the distribution
systems from 3 to 4 wires.
CAUTION: If a three-phase non-linear load is connected to the output, the current on
the neutral conductor can reach a value equal to 1.5 times the value of the phase
current. Dimension the input/output neutral cable appropriately taking this fact into
account .
CAUTION: The UPS cannot feed from a corner ground or mid-point grounded delta
supply source.
CAUTION: Use only lugs or cables with tin-plated eyes for the connections.
CAUTION: Ensure correct phase rotation at the input and output terminals
Ensure correct polarity battery connections
Each model can be configured for a delta input source with a delta connected load or
for a wye input with a wye connected load. If the load requires a neutral connection
(i.e. wye), then an input neutral must be provided. Refer the Power Connection
terminals diagrams later in this section for details concerning configuration of the
neutral to ground bond.
