Trane IntelliPak WEHE Series Installation, Operation And Maintenance Manual page 48

Installation
(cooling mode) values calculated using calculation #1
above. The second set of circuit values shown on the
nameplate will be for the electric heating circuit as follows.
MCA = (1.25 x LOAD 3)
Select a fuse rating for the electric heating circuit that's
equal to the MOP value obtained in the equation above. If
the MOP value does not equal a standard fuse size as listed
in NEC 240 - 6, select the next lower standard fuse rating
(see note below for exception).
Note: If selected MOP is less than the MCA obtained in
the equation above, then select the lowest
standard maximum fuse size which is equal to or
larger than the MCA, provided the selected fuse
size does not exceed 800 amps.
RDE = LOAD 3
Select a fuse rating for the electric heating circuit that's
equal to the RDE value. If the RDE value does not equal a
standard fuse size as listed in NEC 240 - 6, select the next
higher standard fuse rating.
Note: If the selected RDE is greater than the selected MOP
value, then select the RDE value to equal the MOP
value.
Disconnect Switch Sizing (DSS)
Calculation #1 - WX, WF, WL, or WS Single
Power Source Units
DSS = 1.15 X (LOAD 1 + LOAD 2 + LOAD 4)
Calculation #2 - All WEHE Single Power
Source Units
DSS = 1.15 X (LOAD 3 + Supply Fan FLA +
Exhaust Fan FLA.)
PLUS
DSS = 1.15 X (LOAD 1 + LOAD 2 + LOAD 4)
Use the larger value of the two calculations to size the
electrical service.
Calculation #3 - WEHE (200/230 Volt) casing 2
through 6 (20 - 75 Ton Dual Power Source
Units)
DSS = 1.15 X LOAD 3 for the Electric heater AND
Calculation #1 for the Refrigeration Components.
The Rooftop Module (RTM) must have a mode input in
order to operate the rooftop unit. The flexibility of having
several system modes depends upon the type of sensor
and/or remote panel selected to interface with the RTM. An
overall layout of the various control options available for
a Constant Volume application, with the required number
of conductors for each device, is illustrated in
p. 53.
48
MOP = (1.25 x LOAD 3)
Figure 30,
Figure 33, p. 57 illustrates the various control options with
the required number of conductors for a Variable Air
Volume application.
Note: All field wiring must conform to NEC guidelines as
well as state and local codes.
The various field installed control panels, sensors,
switches, and contacts discussed in this section require
both AC and DC consideration. These diagrams are
representative of standard applications and are provided
for general reference only. Always refer to the wiring
diagram that shipped with the unit for specific electrical
schematic and connection information.
WARNING
Hazardous Voltage!
Disconnect all electric power, including remote
disconnects before servicing. Follow proper lockout/
tagout procedures to ensure the power can not be
inadvertently energized. Failure to disconnect power
before servicing could result in death or serious injury.
Controls using 24 VAC
Before installing any connecting wiring, refer to
p. 19 - Figure 8, p. 23 for the electrical access locations
provided on the unit and Table 13
guidelines, and;
a. Use copper conductors unless otherwise specified.
b. Ensure that the AC control wiring between the
controls and the unit's termination point does not
exceed three (3) ohms/conductor for the length of
the run.
Note: Resistance in excess of 3 ohms per conductor may
cause component failure due to insufficient AC
voltage supply.
c. Be sure to check all loads and conductors for
grounds, shorts, and improper wiring.
Figure 4,
for AC conductor sizing
RT-SVX35H-EN