Mitsubishi Electric PAC-AKA51BC Manuel D'installation page 8

9. Electrical work
Branch box
<example>
(5-branch type)
(in case of 2-branch boxes)
Outdoor unit
(A) (A)
L1
L2
Circuit
GR
(C)
breaker
S1
(B)
S2
S3
(C)
Fig. 9-9
Warning:
In case of A-control wiring, there is high voltage potential on the S3 terminal caused by electrical circuit design that has no electrical insulation between power
line and communication signal line. Therefore, please turn off the main power supply when servicing. And do not touch the S1, S2, S3 terminals when the power
is energized. If isolator should be used between outdoor unit and branch box/indoor unit and branch box, please use 3-pole type.
Caution:
After using the isolator, be sure to turn off and on the main power supply to reset the system. Otherwise, the outdoor unit may not be able to detect the
branch box(es) or indoor units.
8
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1
#
Indoor unit
TB3A
(D)
A ROOM
S1 S1
S2 S2
S3 S3
TB2B TB3B
(D) B ROOM
S1 S1 S1
S2 S2 S2
S3 S3 S3
TB3C
(D)
C ROOM
S1 S1
S2 S2
S3 S3
TB3D
(D) D ROOM
S1 S1
S2 S2
S3 S3
TB3E
E ROOM
(D)
S1 S1
S2 S2
S3 S3
Indoor unit
TB3A
(D)
F ROOM
S1 S1
S2 S2
S3 S3
TB3B
G ROOM
(D)
S1 S1
TB2B
S2 S2
S1
S3 S3
S2
S3
TB3C
H ROOM
(D)
S1 S1
S2 S2
S3 S3
Branch box 2
#
(3-branch type)
Power supply
3 poles isolator (Switch)
Isolator (Switch)
S1 S1
Outdoor unit S2 S2
S3 S3
9.2. External wiring procedure (Fig. 9-9)
Power supply: Single phase 08 /30V, 60 Hz
E
Note:
Power supply input: Outdoor unit only. Connect the lines (C), (D) in accor-
1
dance with the terminal block names to ensure correct polarity.
As for lines (C), S1 and S2 are for connecting the power source.
2
And S2 and S3 are for signals. S2 is a common cable for the power source
and signal.
Wire diameter
(A) Main (C) Signal
(B) Ground
power line
10.6 mm² 10.6 mm² 1.65 mm² *
[AWG 7] [AWG 7] [AWG 15]
When using twisted wire for the wiring, the use of round terminal is required.
*1 Refer to the installation manual of the outdoor unit.
* Max 45 m, 147 ft. ("Outdoor unit - Branch box
box # ").
Notes: 1. Wiring size must comply with the applicable local and national
code.
2. Use copper supply wires.
3. Use wires rated 600 V or more for the power supply cables and the
Indoor unit / Branch box / Outdoor unit connecting cables.
4. Install an earth longer than other cables.
S1 S1
"A-control"
Branch
S2 S2
Indoor unit
box
S3 S3
Breaker
(D) Signal Interrupting Performance
line line current characteristic
1.65 mm²
*1
[AWG 15]
# 1" plus " Branch box
*1
# 1 - Branch