Step 9 - Make Electrical Connections - Carrier WeatherMaker 48A020 Installation Instructions Manual

Step 9 — Make Electrical Connections
POWER WIRING — Units are factory wired for the voltage
shown on the unit nameplate.
Provide a unit safety disconnect switch in the main power supply
to each unit (see Fig. 23). Select switch size and mounting loca-
tion in accordance with applicable local codes or National Electri-
cal Code (NEC). If combining the functions of safety disconnect
with maximum overcurrent protection (MOCP) fuses ("fused dis-
connect"), coordinate safety switch size with MOCP size data as
marked on unit informative plate.
Unit may be equipped with optional factory-installed non-fused
disconnect switch (see Fig. 23). Provide maximum overcurrent
protection devices (fuses or HACR breakers, per local codes) in
branch circuit wiring remote from unit. Observe requirements of
NEC Article 440. Install service switch upstream of remote fuses
if required.
The main power terminal block is suitable for use with aluminum
or copper wire. See Fig. 23. Units have circuit breakers for com-
pressors, fan motors, and control circuit. The unit must be electri-
cally grounded in accordance with local codes or, in absence of
local codes, with NEC, ANSI C1-latest year.
FIELD POWER SUPPLY — Unit is factory wired for voltage
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 / -in. NPT coupling for field power wiring and a
2
NPT coupling for 24-v control wiring are provided in basepan.
In the side post, there are two 2
(sizes 040-060) knockouts for the field power wiring. See
Fig. 5-12. If control wiring is to be brought in through side of
unit, a 7 / -in. diameter hole is provided in the condenser side
8
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.
FIELD-INSTALLED DISCONNECT
FACTORY-INSTALLED DISCONNECT
LEGEND
GND — Ground
NEC — National Electrical Code
TB — Terminal Block
Fig. 23 — Field Power Wiring Connections
3 /
4
1 / -in. (sizes 020-035) or 3-in.
2
TB1
FIELD
11
21
POWER
22
12
SUPPLY
13
23
EQUIP GND
OPTIONAL
FACTORY-INSTALLED
DISCONNECT
11 21
22
12
13
23
GND
a48-6977
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
the unit basepan.
Install conduit connector in unit basepan as shown in Fig. 5-12.
Route power and ground lines through connector to terminal con-
nections in unit control box as shown on unit wiring diagram and
Fig. 23.
Use strain relief going into control box through 3
hole provided. After wires are in unit control box, connect to
power terminal block (see Power Wiring section).
Low-voltage wiring must be run in watertight conduit from the
basepan to control box and through
in bottom of unit control box. Field-supplied strain relief must be
used going into the box. After wiring is in control box, make con-
nections to proper terminals on terminal blocks (see Field Control
Wiring section).
Routing Through Side of Unit — Route power wiring in field-
supplied watertight conduit into unit through 2
035) or 3-in. (sizes 040-060) hole.
Use field-supplied strain relief going into control box through 3
in. diameter hole provided. After wires are in unit control box,
connect to power terminal block (see Power Wiring section).
Bring low-voltage control wiring through the
provided in the condenser section side post. Use strain relief going
into 7 / -in. diameter hole in bottom of unit control box.
8
-in.
After wiring is in control box, make connection to proper termi-
nals on terminal blocks (see Field Control Wiring section).
IMPORTANT: The VAV (variable air volume) units use vari-
able frequency drives, which generate and can radiate radio
frequency energy. If units are not installed and used in accor-
dance with these instructions, they may cause radio interfer-
ence. They have been tested and found to comply with limits
of a Class A computing device pursuant to International Stan-
dard in North American EN 61000-2/3, which are designed to
provide reasonable protection against such interference when
operated in a commercial environment.
The unit must be electrically grounded in accordance with
local codes and NEC ANSI/NFPA 70 (National Fire Protec-
tion Association). Personal injury may result.
Affix crankcase heater sticker (located in the installer's packet) to
unit disconnect switch.
Voltage to compressor terminals during compressor operation
must be within the voltage range indicated on the unit nameplate.
Phases must be balanced within 2%.
Use the following formula to determine the percent of voltage
imbalance.
% Voltage Imbalance:
max voltage deviation from average voltage
= 100 x
Example: Supply voltage is 230-3-60
Average Voltage
Determine maximum deviation from average voltage.
(AB) 227-224 = 3 v
(BC) 231-227 = 4 v
(AC) 227-226 = 1 v
Maximum deviation is 4 v.
Determine percent of voltage imbalance.
24
/ -in. diameter hole provided in
1
2
/ -in. diameter hole provided
7
8
7 /
8
WARNING
average voltage
AB = 224 v
A B C
BC = 231 v
AC = 226 v
MOTOR
(224 + 231 + 226) 681
= =
3
/ -in. diameter
5
8
/ -in. (sizes 020-
1
2
⁄ -
5
8
-in. diameter hole
= 227
3