Wall-Mount Unit Wiring; Main Power Wiring; Unit Control Voltage Wiring; 230/208V Wiring - Bard MEGA-TEC W090A Service Instructions Manual

WALL-MOUNT UNIT WIRING

WARNING
!
Electrical shock hazard.
Have a properly trained individual perform
these tasks.
Failure to do so could result in electric shock
or death.

Main Power Wiring

Refer to the unit rating plate or Tables 2A or 2B
for wire sizing information and maximum fuse or
circuit breaker size. Each outdoor unit is marked
with a "Minimum Circuit Ampacity". The field wiring
used must be sized to carry that amount of current.
Depending on the installed KW of electric heat, there
may be two field power circuits required. If this is the
case, the unit rating plate will so indicate. All models
are suitable only for connection with copper wire. Each
unit and/or wiring diagram will be marked "Use Copper
Conductors Only". These instructions must be adhered
to. Refer to the National Electrical Code (NEC) for
complete current carrying capacity data on the various
insulation grades of wiring material. All wiring must
conform to NEC and all local codes.
The unit rating plate and Tables 2A and 2B list fuse
and wire sizes (75°C copper) for all models including
the most commonly used heater sizes. Also shown are
the number of field power circuits required for the
various models with heaters.
The unit rating plate lists a maximum circuit breaker or
fuse that is to be used with the equipment. The correct
size must be used for proper circuit protection and also
to assure that there will be no nuisance tripping due to
the momentary high starting current of the compressor
motor.
The main unit circuit breaker disconnect access is
located on the front panel of the unit.
Route all field power wires in channel under the control
panel. See Figure 10 to reference VAC landing points.
Route wires into unit through recommended side
entrances (see Figure 11 on page 16). Optional rear
entry points are also available (see Figure 12 on page
16).
NOTE: Field wires enter at bottom for line side
connection.
When running wires to unit from shelter, be careful to
not place wiring and conduit where it will interfere with
opening filter access doors.
Manual 2100-705B
Page 14 of 43
FIGURE 10
VAC Supply Wiring Landing Points
230/208V

Unit Control Voltage Wiring

NOTE: The voltage should be measured at the field
power connection point in the unit and while
the unit is operating at full load (maximum
amperage operating condition.

230/208V Wiring

230/208V 3 phase equipment use dual primary voltage
transformers. All equipment leaves the factory wired on
240V tap. It is very important that the correct voltage
tap is used. For 208V operation, reconnect from 240V
to 208V tap. The acceptable operating voltage range
for the 240 and 208V taps are: 240V tap (253 – 216)
and 208 tap (220 – 197).

460V Wiring

460V 3 phase equipment use triple primary voltage
transformers. All equipment leaves the factory wired on
480V tap. It is very important that the correct voltage
tap is used. The acceptable operating voltage range for
the 480V, 415V and 380V taps are: 480V tap (429
and above), 415 Tap (395 – 428) and 380 tap (below
395).
NOTE: 575V models take incoming field power and step-
down secondary to 460V which supplies most
components except compressors and electric heat
which remain 575V. Reference wiring diagrams
for more information.
For communication wiring, a
coded shielded cable with drain
460V
2-wire, 18 gauge color-
is recommended.