109
ENGLISH
Field wiring guidelines
Most field wiring on the unit is to be made on the terminal block inside the switch box. To gain access to the terminal block, remove
the switch box service panel (door 2).
b
WARNING
Switch off all power including the unit power supply and backup heater and domestic hot water tank power supply (if applicable) before
removing the switch box service panel.
Fix all cables using cable ties.
A dedicated power circuit is required for the backup heater.
Installations equipped with a domestic hot water tank (field supply) require a dedicated power circuit for the booster heater. Please refer to
the domestic hot water tank Installation & Owner's Manual. Secure the wiring in the order shown below.
Lay out the electrical wiring so that the front cover does not rise up when doing wiring work and attach the front cover securely.
Follow the electric wiring diagram for electrical wiring works (the electric wiring diagrams are located on the rear side of door 2).
Install the wires and fix the cover firmly so that the cover may be fit in properly.
9.7.3
Precautions on wiring of power supply
Use a round crimp-style terminal for connection to the power supply terminal board. In case it cannot be used due to unavoidable
reasons, be sure to observe the following instructions.
-
Do not connect different gauge wires to the same power supply terminal. (Loose connections may cause overheating.)
-
When connecting wires of the same gauge, connect them according to the figure below.
Use the correct screwdriver to tighten the terminal screws. Small screwdrivers can damage the screw head and prevent appropriate
tightening.
Over-tightening the terminal screws can damage the screws.
Attach a ground fault circuit interrupter and fuse to the power supply line.
In wiring, make certain that prescribed wires are used, carry out complete connections, and fix the wires so that outside force
cannot affect the terminals.
9.7.4
Safety device requirement
1. Select the wire diameters( minimum valve) individually for each unit based on the table 9-1 and table 9-2, where the rated current in
table 9-1 means MCA in table 9-2. In case the MCA exceeds 63A, the wire diameters should be selected according to the national wiring
regulation.
2. Maximum allowable voltage range variation between phases is 2%.
3. Select circuit breaker that having a contact separation in all poles not less than 3 mm providing full disconnection, where MFA is used to
select the current circuit breakers and residual current operation breakers.
Table 9-1
Rated current of appliance (A):
Nominal cross-sectional area (mm
2
)
Flexible cords
Cable for fixed wiring
≤3
0.5 and 0.75
1 and 2.5
>3 and ≤6
0.75 and 1
1 and 2.5
>6 and ≤10
1 and 1.5
1 and 2.5
>10 and ≤16
1.5 and 2.5
1.5 and 4
>16 and ≤25
2.5 and 4
2.5 and 6
>25 and ≤32
4 and 6
4 and 10
>32 and ≤50
6 and 10
6 and 16
>50 and ≤63
10 and 16
10 and 25
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