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7. ELECTRICAL WIRING
7.1. Safety precautions for electrical wiring
Electrical work must be performed in accordance with this Manual by a person
certifi ed under the national or regional regulations. Be sure to use a dedicated circuit
for the unit.
An insufficient power supply circuit or improperly performed electrical work can
cause serious accidents such as electric shock or fi re.
Before starting work, check that power is not being supplied to the RB unit, indoor
unit and outdoor unit.
For wiring, use the prescribed type of cables, connect them securely, making sure
that there are no external forces of the cables applied to the terminal connections.
Improperly connected or secured cables can cause serious accidents such as
overheating the terminals, electric shock, or fi re.
Securely install the electrical box cover on the unit.
An improperly installed electrical box cover can cause serious accidents such as
electric shock or fi re through exposure to dust or water.
Use the included connection cables and power cables or ones specified by the
manufacturer. Improper connections, insufficient insulation, or exceeding the
allowable current can cause electric shock or fi re.
Do not modify the power cables, use extension cables, or use any branches in the
wiring. Improper connections, insufficient insulation, or exceeding the allowable
current can cause electric shock or fi re.
Match the terminal block numbers and connection cable colors with those of the
indoor unit or outdoor unit. Erroneous wiring may cause burning of the electric parts.
Securely connect the connection cables to the terminal board. In addition, secure
the cables with wiring holders. Improper connections, either in the wiring or at the
ends of the wiring, can cause a malfunction, electric shock, or fi re.
Always fasten the outside covering of the connection cable with the cable clamp. (If
the insulator is chafed, electric discharge may occur.)
Install an earth leakage breaker. In addition, install the earth leakage breaker so
that the entire AC main power supply is cut off at the same time. Otherwise, electric
shock or fi re could result.
Always connect the earth (ground) cable.
Improper earthing (grounding) work can cause electric shocks.
Perform wiring work in accordance with standards so that the air conditioner can be
operated safely and positively.
If the supply cable is damaged, it must be replaced by the manufacturer, its service
agent or similarly qualifi ed persons in order to avoid a hazard.
Earth (Ground) the unit.
Do not connect the earth (ground) cable to a gas pipe, water pipe, lightning rod, or
a telephone earth (ground) cable.
Improper earthing (grounding) may cause electric shock.
Do not connect power supply cables to the transmission terminals, as this will
damage the product.
Never bundle the power supply cable and transmission cable, together.
Separate these cable by 50 mm or more.
Bundling these cables together will cause miss operation or breakdown.
When handling PC board, static electricity charged in the body may cause
malfunction of the PC board. Follow the cautions below:
• Establish an earth (ground) for the RB units , indoor units, outdoor units and
peripheral devices.
• Cut power (breaker) off.
• Touch metal part of the RB units, indoor units and outdoor units for more than
10 seconds to discharge static electricity charged in the body.
• Do not touch terminals of parts and patterns implemented on PC board.
En-7
WARNING
CAUTION
7.2. Electrical requirement
Voltage rating
230 V
Operating range
198 to 264 V
• Select the power cable type and size in accordance with relevant local and national
regulations.
• Specifi cations for local wiring power cord and branch wiring are in compliance with
local code.
• Max. wire length: Set a length so that the voltage drop is less than 2%. Increase the
wire diameter when the wire length is long.
Breaker should be installed at every refrigerant system. Do not use a breaker in a
different refrigerant system.
Refer to the table for the breaker specifi cations of each installation condition. Perform
the power crossover wiring within the range of the same refrigerant system. When the
crossover wiring is done, make a connection for RB units to satisfy conditions A and B
below.
A. Current breaker requirements
Model
MCA
UTP-RX08AH
1.04 A
UTP-RX12AH
1.56 A
MCA: Minimum Circuit Ampacity
MFA: Maximum Fuse Ampacity
When the power crossover wiring is done, make it so that the total of the MCA of the
connected RB units and indoor units does not exceed the 15 A. For indoor unit MCA,
refer to the indoor unit installation manual.
If the capacity of connected RB units and indoor units exceeds the upper limit, either
add breakers or use a breaker with a greater capacity.
B. Earth leakage breaker requirements
Breaker capacity
30 mA, 0.1 sec or less
100 mA, 0.1 sec or less
* If the total number of units connected to the breaker exceeds 44, either add a 30mA
breaker, or use breakers with a greater capacity.
7.2.1. Cable specifi cations
Follow the specifi cations below for the power supply and transmission cable.
Recommended
cable size
2
(mm
)
Power supply
2.5
cable
Transmission
0.33
cable
7.3. Wiring
7.3.1. Power supply cable
Keep the ground cable longer than the other cables.
Earth (Ground)
cable
Power supply cable
(1) Use ring terminals with insulating sleeves as shown in the fi gure below to connect
to the terminal block.
(2) Securely clamp the ring terminals to the cables using an appropriate tool so that the
cables do not come loose.
(3) Use the specifi ed cables, connect them securely, and fasten them so that there is
no stress placed on the terminals.
MFA
20 A
20 A
Connectable RB units and indoor units
44 or less *
45 to 148
Cable type
Remark
Type60245
1ø 50 Hz 198 to 264 V
IEC57 or
2 Cable + earth (ground)
equivalent
22 AWG LEVEL 4
LONWORKS
(NEMA) non-polar 2
compatible
core, twisted pair solid
cable
core diameter 0.65 mm
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