Electrical Service Sizing; Set 1: Cooling Only Rooftop Units And Cooling With Gas Heat Or Hydronic Heat Rooftop Units; Set 2: Rooftop Units With Electric; Heat - Trane IntelliPak 1 with Symbio 800 Installation, Operation And Maintenance Manual

Installation
Table 22. Customer connection wire range
Notes
Terminal block and STD SCCR disconnect switch sizes are
calculated by selecting the size greater than or equal to 1.15 X
sum of unit loads). See unit literature for unit load values.
High SCCR disconnect switch sizes are calculated by selecting
the size greater than or equal to 1.25 X (sum of unit loads). See
unit literature for unit load values.
(a) 250A Components may require lug kit S1A59551 to be installed to allow for connection to 4 - 2/0 AWG wires. When needed, this kit is provided with the unit.
250A Disconnect switch wire binding screws
The 250A disconnect switch (standard and high SCCR)
installed for main power connection accommodates 4 AWG
– 350 kcmil wires on the "OFF" side. As shipped from the
factory, the wire binding screws only accommodate 3/0
AWG – 350 kcmil wires. If 4 AWG – 2/0 AWG field power
wiring is used, then the factory installed wire binding
screws must be replaced with those that are provided with
the kit installed near the disconnect switch (these screws
should have a blue top surface). See the kit for instructions
on changing the wire binding screws.

Electrical Service Sizing

To correctly size electrical service wiring for a unit, find the
appropriate calculations listed below. Each type of unit has
its own set of calculations for MCA (Minimum Circuit
Ampacity) and MOP (Maximum Overcurrent Protection).
Read the load definitions that follow and then find the
appropriate set of calculations based on unit type.
Note: Set 1 is for cooling only, cooling with gas heat, or
cooling with hot water/steam heat units. Set 2 is for
cooling with electric heat units
Load Definitions: (To determine load values, see the
Electrical Service Sizing Data Tables on the following
page.)
LOAD1 = Current of the largest motor (compressor or fan
motor)
LOAD2 = Sum of the currents of all remaining motors
LOAD3 = Current of electric heaters
LOAD4 = Any other load rated at 1 AMP or more
SAH_ (Cooling Only) units
SEH_ (Cooling with Electric Heat) units
SXH_ (Extended Casing Cooling Only) units
SLH_ and SSH_ (Cooling with Hydronic Heat) units
52
Component type/size
510A terminal block
760A terminal block
150A disconnect switch (Std SCCR)
250A disconnect switch (Std SCCR)
400A disconnect switch (Std SCCR)
600A disconnect switch (Std SCCR)
150A disconnect switch (High SCCR)
250A disconnect switch (High SCCR)
400A disconnect switch (High SCCR)
600A disconnect switch (High SCCR)
SFH_ (Cooling with Gas Heat) units
Load Definitions
Current (RLA, MRC, FLA or MOC) of the largest motor
LOAD 1
(compressor or fan motor)
Sum of the currents (RLA, MRC, FLA or MOC) of all
LOAD 2
remaining motors
LOAD 3 Current of electric heaters
Any other load rated at 1 amp or more
LOAD 4
Load 4 — Control Power Transformer Loads for All Modes
200V
10.0
20–75
Amps
ton units
90–130
—
ton units
Set 1: Cooling Only Rooftop Units and
Cooling with Gas Heat or Hydronic Heat
Rooftop Units
MCA = (1.25 x LOAD1) + LOAD2 + LOAD4
MOP = (2.25 x LOAD1) + LOAD2 + LOAD4
Select a fuse rating equal to the MOP value. If the MOP
value does not equal a standard fuse size as listed in NEC
240-6, select the next lower standard fuse rating.
Note: If selected MOP is less than the MCA, 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.
Set 2: Rooftop units with Electric Heat
Single Source Power units (460V and 575V)
Wire qty per
Wire range
phase
2 6 AWG - 250 kcmil
2 4 AWG - 500 kcmil
1 14 AWG - 1/0 AWG
4 AWG - 350 kcmil
1
2 2/0 AWG - 500 kcmil
2 2/0 AWG - 500 kcmil
1 14 AWG - 1/0 AWG
4 AWG - 350 kcmil
1
2 2/0 AWG - 500 kcmil
2 2/0 AWG - 500 kcmil
230V 460V 575V
9.0 4.5
3.5 Amps
Amps Amps
9.0
7.0 Amps
—
Amps
RT-SVX072D-EN
(a)
(a)