5
Service Wiring - North America cont’d
208V 3-Phase Wye-Connected
With a Wye-connected secondary, any two of
the legs can be used to provide 208V to the
High Power Wall Connector. For example, L1
and L2, or L1 and L3, or L2 and L3. The two
used phases must each measure 120V to
neutral.
NOTE: A current-carrying neutral is not
required.
CAUTION: The unused leg (L3 in the
illustration) must remain open. Do not
connect to a neutral bar, or to ground.
CAUTION: The center point of the 3
phases (normally used as neutral) must
be grounded to earth at only one point. This is
usually at the breaker panel.
240V 3-Phase Delta-Connected
With the delta connection, one leg must be
center tapped, and only the two phases on
either side of the center tap can be used. The
two used phases must each measure 120V to
neutral.
Consult the transformer manufacturer’s
literature to verify that the single leg can
supply the required power.
NOTE: The High Power Wall Connector’s
contactor closes only if it detects the presence
of a Ground wire connected to a neutral point
on the transformer secondary.
CAUTION: The third line (L3 in the
illustration) of the delta is 208V, with
respect to neutral, and is sometimes referred
to as a “stinger.” Do not use this third line.
CAUTION: Do not use a 3-phase
delta-connected transformer secondary
without a center tap on one leg. No “neutral”
point is available for the required ground
connection.
120V
120V
NEUTRAL
(NOT USED)
GND
L1
L2
L3 (NOT USED)
208V
.
.
L3 (NOT USED)
L1
L2
GND
NEUTRAL
(NOT USED)
120V
120V
240V
. . .
.
HPWC_Install_Guide.book Page 5 Wednesday, April 2, 2014 3:30 PM
