22
Unit may be equipped with optional factory-installed non-
fused disconnect switch (see Fig. 20). Provide maximum over-
current protection devices (fuses or UL489 rated breakers, per
local codes) in branch circuit wiring remote from unit. Observe
requirements of NEC Article 440. Install service switch up-
stream of remote fuses if required.
The main power terminal block is suitable for use with alu-
minum or copper wire. See Fig. 20. Units have circuit breakers
for compressors, fan motors, and control circuit. If required by
local codes, provide an additional disconnect switch. Unit must
be electrically grounded in accordance with local codes or, in
absence of local codes, with NEC, ANSI (American National
Standards Institute) C1-latest year.
FIELD POWER SUPPLY — Unit is factory wired for volt-
age shown on unit nameplate.
Field wiring can be brought into the unit from bottom
(through basepan and roof curb) or through side of unit (corner
post next to control box).
A 3
1
/
2
-in. NPT coupling for field power wiring and a
3
/
4
-in.
NPT coupling for 24-v control wiring are provided in basepan.
In the side post, there are two 2
1
/
2
-in. (sizes 020-035) or 3-in.
(sizes 040-060) knockouts for the field power wiring. See
Fig. 6-13. If control wiring is to be brought in through side of
unit, a
7
/
8
-in. diameter hole is provided in the condenser side
post next to the control box.
Do not route control wiring in the same conduit as power
wiring.
If disconnect box is mounted to corner post, be careful not
to drill or screw into the condenser coil.
Routing Through Bottom of Unit — If wiring is brought in
through bottom of unit, use field-supplied watertight conduit to
route power wiring through the 3
1
/
2
-in. diameter hole provided
in the unit basepan.
Install conduit connector in unit basepan as shown in Fig. 6-
13. Route power and ground lines through connector to termi-
nal connections in unit control box as shown on unit wiring di-
agram and Fig. 20.
Use strain relief going into control box through 3
5
/
8
-in. di-
ameter hole provided. After wires are in unit control box, con-
nect to power terminal block (see Power Wiring section on
Low-voltage wiring must be run in watertight conduit from
the basepan to control box and through
7
/
8
-in. diameter hole
provided in bottom of unit control box. Field-supplied strain re-
lief must be used going into the box. After wiring is in control
box, make connections to proper terminals on terminal blocks
(see Field Control Wiring section on page 23).
Routing Through Side of Unit — Route power wiring in
field-supplied watertight conduit into unit through 2
1
/
2
-in. (siz-
es 020-035) or 3-in. (sizes 040-060 units) hole.
Use field-supplied strain relief going into control box
through 3
5
/
8
-in. diameter hole provided. After wires are in unit
control box, connect to power terminal block (see Power Wir-
Bring low-voltage control wiring through the
7
/
8
-in. diame-
ter hole provided in the condenser section side post. Use strain
relief going into
7
/
8
-in. diameter hole in bottom of unit control
box.
After wiring is in control box, make connection to proper
terminals on terminal blocks (see Field Control Wiring section
Affix crankcase heater sticker (located in the installer’s
packet) to unit disconnect switch.
Fig. 19 — Condensate Drain Trap Piping Details
(Typical Roof Curb or Slab Mount Shown)
a48-3714
IMPORTANT: The variable air volume units use variable
frequency drives, which generate and can radiate radio fre-
quency energy. If units are not installed and used in accor-
dance with these instructions, they may cause radio
interference. They have been tested and found to comply
with limits of a Class A computing device pursuant to Inter-
national Standard in North American FN 61000-2/3, which
are designed to provide reasonable protection against such
interference when operated in a commercial environment.
WARNING
The unit must be electrically grounded in accordance with
local codes and NEC ANSI/NFPA 70 (National Fire Pro-
tection Association). Failure to ground unit could cause
personal injury.
Fig. 20 — Field Power Wiring Connections
LEGEND
GND —
Ground
NEC —
National Electrical Code
TB
—
Terminal Block
a48-6977
FIELD
S
UPPLIED
DI
S
CONNECT
PER NEC
FIELD
POWER
S
UPPLY
11
21
22
2
3
1
3
12
TB1
EQUIP GND
FIELD POWER WIRING
11
21
22
2
3
1
3
12
GND
OPTIONAL
FACTORY-IN
S
TALLED
DI
S
CONNECT
FIELD-IN
S
TALLED DI
S
CONNECT
FACTORY-IN
S
TALLED DI
S
CONNECT