Mitsubishi Electric EHST20C-VM2C.UK Service Manual page 18

<3 phase>
Affix label A that is included with the manuals near each
wiring diagram for cylinder unit and outdoor units.
Power
Earth
supply
leakage
3N~
circuit
400 V
breaker
50 Hz
*1
Power supply
3~ 400 V 50 Hz (EH*T20*-YM*C)
3~ 230 V 50 Hz (EH*T20*-TM*C)
Description
Booster heater (Primary circuit)
Immersion heater (DHW tank)
Cylinder unit - Outdoor unit
Cylinder unit - Outdoor unit earth
Cylinder unit - Outdoor unit S1 - S2
Cylinder unit - Outdoor unit S2 - S3
*1. A breaker with at least 3.0 mm contact separation in each pole shall be provided. Use earth leakage breaker (NV).
The breaker shall be provided to ensure disconnection of all active phase conductors of the supply.
*2. Max. 45 m
If 2.5 mm² used, Max. 50 m
If 2.5 mm² used and S3 separated, Max. 80 m
*3. The values given in the table above are not always measured against the ground value.
Note: 1. Wiring size must comply with the applicable local and national codes.
2. Indoor unit/outdoor unit connecting cords shall not be lighter than polychloroprene sheathed flexible cord. (Design 60245 IEC 57)
Indoor unit power supply cords shall not be lighter than polychloroprene sheathed flexible cord. (Design 60227 IEC 53)
3. Install an earth longer than other cables.
4. Please keep enough output capacity of power supply for each heater. Insufficient power supply capacity might cause chattering.
OCH570
Outdoor unit
L1
Wiring
L2
circuit
breaker
L3
or
Isolating
N
switch
breaker
Isolating
Power
supply
~/N breaker
230 V
50 Hz Isolating
<Figure 7-2>
Electrical connections 3 phase
Power supply Capacity (Indoor unit Ref.) Breaker
3~ 400 V 50 Hz 9 kW
3~ 230 V 50 Hz 9 kW
~/N 230 V 50 Hz 3 kW
*2 3 × 1.5 (polar)
*2 1 × Min. 1.5
*3
*3
Cylinder unit
TB1
L
N
To control
board
S1 S1
S2 S2
S3 S3
ECB1
For
L1
Wiring booster
circuit heater
L2
(Primary circuit)
or
L3
switch
ECB2
For
Wiring L
Immersion
circuit
heater
N
(DHW tank)
or
switch
Wiring
16 A *1 2.5 mm²
32 A *1 6.0 mm²
16 A *1 2.5 mm²
230 V AC
24 V DC
18
*1 If the installed earth leakage circuit breaker
does not have an over-current protection
function, install a breaker with that function
along the same power line.