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Installation Electrical
WARNING
Proper Field Wiring and Grounding
Required!
Failure to follow code could result in death or serious
injury. All field wiring MUST be performed by qualified
personnel. Improperly installed and grounded field
wiring poses FIRE and ELECTROCUTION hazards. To
avoid these hazards, you MUST follow requirements for
field wiring installation and grounding as described in
NEC and your local/state electrical codes.
General Recommendations
WARNING
Hazardous Service Procedures!
Failure to follow all precautions in this manual and on
the tags, stickers, and labels could result in death or
serious injury.
Technicians, in order to protect themselves from
potential electrical, mechanical, and chemical hazards,
MUST follow precautions in this manual and on the
tags, stickers, and labels, as well as the following
instructions: Unless specified otherwise, disconnect all
electrical power including remote disconnect and
discharge all energy storing devices such as capacitors
before servicing. Follow proper lockout/tagout
procedures to ensure the power can not be
inadvertently energized. When necessary to work with
live electrical components, have a qualified licensed
electrician or other individual who has been trained in
handling live electrical components perform these
tasks.
NOTICE
Use Copper Conductors Only!
Failure to use copper conductors could result in
equipment damage as unit terminals are not designed
to accept other types of conductors.
The wiring procedures, as described in this portion of the
manual, must be accomplished to obtain proper operation of
the unit.
All wiring must comply with National Electrical Code (NEC) and
state and local requirements. Outside the United States, the
national and/or local electrical requirements of other countries
shall apply. The installer must provide properly sized system
interconnecting and power supply wiring with appropriate
fused disconnect switches. Type and locations of disconnects
must comply with all applicable codes.
Minimum circuit ampacity, recommended fuse sizes and other
unit electrical data are provided
the unit nameplate.
30
"Electrical Data," p. 10
and on
Checking the Power Supply
Electrical power to the unit must meet stringent requirements
for the unit to operate properly. Total voltage supply and
voltage imbalance between phases should be within the
tolerances listed in this manual.
Total Supply Voltage
WARNING
Live Electrical Components!
Failure to follow all electrical safety precautions when
exposed to live electrical components could result in
death or serious injury. When necessary to work with
live electrical components, have a qualified licensed
electrician or other individual who has been properly
trained in handling live electrical components perform
these tasks.
Measure each leg of the supply voltage at the line voltage
disconnect switches. For units with a nameplate voltage of
208/230 volt, the readings must fall within the range of 180-253
volts. For units with a nameplate voltage of 460 volts, the
readings must fall within the range of 414-506 volts. If voltage
on any leg does not fall within tolerance, notify the power
company and request correction of this situation before
connecting to or operating the unit. Inadequate voltage to the
unit will shorten the life of relay contacts and compressor
motors.
Voltage Imbalance Between Phases
Excessive voltage imbalance between phases in a three-
phase system will cause motors to overheat and eventually
fail. Maximum allowable imbalance is 2 percent. Voltage
imbalance is defined as 100 times the maximum deviation of
the three voltages (three phases) subtracted from the average
(without regard to sign), divided by the average voltage.
EXAMPLE:
If the three voltages measured at the line voltage fused
disconnect are 221 volts, 230 volts and 227 volts, the average
would be:
221 + 230 + 227
3
The percentage of imbalance is then:
100 (226 - 221)
226
In the preceding example, 221 is used because it is the farthest
from the average. The 2.2 percent imbalance that exists
exceeds maximum allowable imbalance by 0.2 percent. This
much imbalance between phases can equal as much as 20
percent current imbalance with a resulting increase in winding
temperature that will decrease compressor motor life.
=
226 volts
=
2.2%
CG-SVX044F-EN
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