Trane SCWH - Manual (Page 19)

PKG-SVX14A-EN 19
electrical
requirements Installation
Supply Power Wiring
It is the installer’s responsibility to provide
power supply wiring to the unit terminal
block or the non-fused disconnect switch
option. Wiring should conform to NEC and
all applicable code requirements.
1. Verify the power supply available is
compatible with the unit nameplate
ratings. The supply power must be
within 10%of the rated voltage listed on
the unit nameplate.
2. Reference the electrical data in Table I-
ER-1. Protect the electrical service from
over current and short circuit
conditions in accordance with NEC
requirements. Size protection devices
according to the electrical data on the
unit nameplate.
3. If using a field-supplied disconnect,
install it at or near the unit in
accordance with NEC. Do not mount a
field-supplied disconnect on the unit.
Reference the electrical service
entrance location on unit submittals.
4. Complete the unit power wiring
connections onto either the main
terminal block or the field-provided non-
fushed disconnect switch.
5. Provide proper unit grounding in
accordance with local and national
codes.
Electrical Data Calculations
RLA = rated load amps
Compressor LRA = locked rotor amps
Fan motor LRA = locked rotor amps,
N.E.C. Table 430 - 151
FLA = Full load amps, N.E.C.
Table 430 - 150
Voltage utilization range is ±10%
Minimum circuit ampacity (MCA)
= 1.25 x largest motor amps (FLA or
RLA) + the sum of the remaining motor
amps.
Maximum fuse size (MFS) and maximum
circuit breaker size (MCB) = 2.25 x largest
motor amps (FLA or RLA) + the sum of
the remaining motor amps.
Note: If the rating value determined does
not equal a standard current rating of
over current protective device, use the
next lower standard rating for the
marked maximum rating.
Voltage Range
Voltages must be within +- 10% the
nameplate voltage. Ensure the unit
voltage is balanced by measuring at the
compressor terminals. Voltage imbalance
on three phase systems can cause motor
overheating and premature failure.
Maximum allowable imbalance is 2.0%.
Voltage Imbalance
Read the voltage at the compressor
terminals to determine if it is balanced.
Voltage imbalance on three phase
systems can cause motor overheating
and premature failure. The maximum
allowable imbalance is 2.0%. Voltage
imbalance is defined as 100 times the
sum of the deviation of the three voltages
from the average (without regard to sign)
divided by the average voltage. For
example, if the three measured voltages
are 221, 230, and 227, the average
voltage would be:
(221 + 230 + 227) = 226 volts
3
The percentage of voltage imbalance is
then:
100 * (226-221) = 2.2%
226
In this example, 2.2% imbalance is not
acceptable. Whenever a voltage
imbalance of more than 2.0% exists,
check the voltage at the unit disconnect
switch. If the imbalance at the unit
disconnect switch does not exceed 2.0%,
faulty unit wiring is causing the
imbalance. Conduct a thorough
inspection of the unit electrical wiring
connections to locate the fault, and make
any repairs necessary.
WARNING
Live Electrical Components!
During installation, testing, servicing,
and troubleshooting this equipment, it
may be necessary to work with live
electrical components. Have a
qualified licensed electrician or other
individual who is properly trained in
handling live electrical components
perform these tasks. Failure to follow
all electrical safety precautions when
exposed to live electrical components
could result in death or serious injury.
WARNING
Hazardous Voltage!
Disconnect all electric power,
including remote disconnects before
servicing. Follow proper lockout/
tagout procedures to ensure power
cannot be inadvertently energized.
Failure to disconnect power before
servicing could result in death or
serious injury.
CAUTION
Use Copper Conductors Only!
Unit terminals are not designed to
accept other type conductors. Failure
to use copper conductors may result
in equipment damage.
WARNING
Ground Wire!
All field-installed wiring must be
completed by qualified personnel.
All field-installed wiring must
comply with NEC and applicable
local codes. Failure to follow this
instruction could result in death
or serious injuries.
WARNING
Grounding Required!
Follow proper local and state elec-
trical code on requirements for
grounding. Failure to follow code
could result in death or serious in-
jury.