Installation manual

Planning
2–4 153396 Revision D
This manual is for use by qualified installers only
Ground Requirements
This product is intended to be installed as part of a permanently grounded
electrical system per the National Electrical Code ANSI/NFPA 70, as well as all
state and local code requirements. A copper clad earth grounding electrode
must be installed within 1 m (3 ft.) of the Xantrex GT250 enclosure. This is to be
the single point earth ground for the inverter system. The single point connection
to the earth grounding electrode for the inverter system is to be made at the AC
ground bus bar (TB2).
System Neutral Requirements
The Xantrex GT250 is designed to be installed as a four-wire system. As required
by the UL 1741 listing, a neutral conductor from the utility-interconnect must be
terminated at TB1-N within the AC interface to ensure that the AC voltage
sensing circuit can perform an individual phase voltage (line-to-neutral)
measurement. The function of the neutral connection is to provide a point of
reference for measurement purposes that is essentially at ground potential.
No power will flow through the neutral conductor.
Inverter Isolation Transformer
The Xantrex GT250 includes a custom, high-efficiency, isolation transformer. The
utility side windings of the isolation transformer are configured Wye and must
match the voltage at the utility inter-tie. The Xantrex GT250 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 both the Primary and Secondary windings. Connection of these neutral
terminals will affect the operation of the Xantrex GT250 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.
CAUTION: Equipment Damage
If the isolation transformer neutral (H0 and X0) terminals are tied to ground, they
may cause irreparable damage to the Xantrex GT250.