Installation manual

Planning
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This manual is for use by qualified personnel only.
Utility Side Isolation Transformer Requirements
The Xantrex GT250 E may be supplied with a custom, high-efficiency, isolation
transformer as a separate component. The utility side windings of the isolation
transformer are configured Wye and must match the voltage at the utility inter-tie.
The Xantrex GT250 E is a balanced, three-phase, current-sourcing inverter and
only operates with the presence of a stable utility voltage. The transformer is also
supplied with a neutral connection on the utility interconnect. Connection of this
utility-side neutral does not affect the operation of the inverter, however
connection of the neutral on the inverter-side does affect the operation and must
be left floating or disconnected. Single-phase, grounded loads which may be
present between the transformer and utility, will maintain their existing ground
reference at the utility distribution transformer.
WARNING: Lethal Voltage
Grounding the neutral of a Wye-wound transformer may create an “open delta”
condition, depending on the utility configuration. This condition may keep the
Xantrex GT250 E from detecting a loss of phase condition on the utility system,
which may allow potentially lethal voltage to be present on the open-phase
wiring.
CAUTION: Equipment Damage
If the Isolation Transformer neutral terminal is tied to ground, it will cause
irreparable damage to the Xantrex GT250 E. Check local regulations for their
requirements regarding the connection of these neutrals.