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3. Electrical Wiring
3. Electrical Wiring
Example of Communication Cabling:
ATTENTION:
Disconnect all power at the main power source before performing electrical work. Failure to do this can result
in fire, damage to internal components, and severe or fatal electrical shock.
Controller
M3
Screws
A. Communication cabling must be a minimum of 18-Gauge, 2-Conductor, Stranded Copper. Shielded cable must
be considered for applications and routing in areas of high electronic interference (EMI) and other sources of
potentially excessive electrical noise to reduce the potential for communication errors. When shielded cabling
is applied, proper bonding and termination of the cable shield is required as per Johnson Controls-Hitachi
Air Conditioning guidelines. Plenum and riser ratings for communication cables must be considered per
application and local code requirements. The use of any other grade of cable other than that specified above
can result in damage from EMI.
B. Maintain a distance more than 11-13/16 inches (30cm) between the communication cables (controller cable
and communication cables) and power source of the indoor units. If this is not done, the unit can malfunction
due to EMI generated by incoming power cables from the power source.
C. In systems where multiple indoor units are in synchronized control under a single controller, assign the
refrigerant cycle numbers and address for indoor units without duplication.
D. Refer to the "Unit No. Setting" of each Installation and Maintenance manual provided with indoor unit when
performing electrical wiring work between the controller and indoor units for setting the refrigerant cycle
number and the indoor unit address.
E. No gap should exist between the controller cable and the cable access inlet of the controller box casing. If
there is a gap, cover and seal the gap with vinyl tape. Failure to insulate against the penetration of moisture
and insects can result in degraded performance and damage to the unit.
F. If case of operating with two controllers (Primary and Secondary), set the primary and secondary controllers
by selecting the appropriate function for those controllers. Refer to Page 12 item F2 in chapter 6. Function
Selection. After this is set, turn OFF the power supply to all indoor units connected to these controllers.
6
Max. 16 Indoor Units
Electrical Box
of Indoor Unit
Terminal Board
A
B
M3.5
A
B
Screws
Use AWG 18 (0.82mm ) cable, (18-Gauge, 2-Conductor, Stranded Copper).
Electrical Box
of Indoor Unit
Terminal Board
A
B
M3.5
Screws
Controller
(Secondary)
A
B
A16381TMF2
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