RT-SVX072A-EN
53
CUSTOMER CONNECTION WIRE RANGE
NOTES:
COMPONENT
TYPE/SIZE
WI-
RE
QTY
PER
PH-
ASE
WIRE
RANGE
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.
510A
TERMINAL
BLOCK
2
6 AWG -
250 kcmil
760A
TERMINAL
BLOCK
2
4 AWG -
500 kcmil
150A
DISCONNECT
SWITCH (STD
SCCR)
1
14 AWG -
3/0 AWG
250A
DISCONNECT
SWITCH (STD
SCCR)
1
3/0 AWG
- 350
kcmil
(a)
400A
DISCONNECT
SWITCH (STD
SCCR)
2
2/0 AWG
- 500
kcmil
600A
DISCONNECT
SWITCH (STD
SCCR)
2
2/0 AWG
- 500
kcmil
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.
150A
DISCONNECT
SWITCH (HIGH
SCCR)
1
14 AWG -
3/0 AWG
250A
DISCONNECT
SWITCH (HIGH
SCCR)
1
3/0 AWG
- 350
kcmil
(a)
400A
DISCONNECT
SWITCH (HIGH
SCCR)
2
2/0 AWG
- 500
kcmil
600A
DISCONNECT
SWITCH (HIGH
SCCR)
2
2/0 AWG
- 500
kcmil
(a)
250A DISCONNECT SWITCHES CAN ACCOMMODATE 4 AWG - 4/0
AWG IF LUG SCREWS ARE CHANGED TO S1A59551 KIT (PROVIDED
WITH UNIT)
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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.
NNoottee:: 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
SFH_ (Cooling with Gas Heat) units
Load Definitions
LOAD 1
Current (RLA, MRC, FLA or MOC) of the largest motor
(compressor or fan motor)
LOAD 2
Sum of the currents (RLA, MRC, FLA or MOC) of all
remaining motors
LOAD 3 Current of electric heaters
LOAD 4
Any other load rated at 1 amp or more
Load 4 — Control Power Transformer Loads for All
Modes
200V 230V 460V 575V
20–75
ton
units
10.0
Amps
9.0
Amps
4.5
Amps
3.5 Amps
90–130
ton
units
— —
9.0
Amps
7.0 Amps
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.
IInnssttaallllaattiioonn
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