Mitsubishi Electric MXZ-8C48NA Manuel D'installation page 14

7. Electrical work
Thickness of Wire for Main Power Supply and On/Off Capacities
Model
4C36/5C5/
8C48NAHZ
Outdoor Unit ~ (single), 60 Hz, 08/30 V
8C48NA
Indoor Unit ~ (single), 60 Hz, 08/30 V
*1. A breaker with at least 3.0 mm [1/8 inch] contact separation in each poles shall be provided. Use non-fuse breaker (NF) or earth leakage breaker (NV).
*2. Use copper supply wires. Use the electric wires over the rating voltage 300 V.
Total operating current of the indoor unit
F0 = 15A or less *
F0 = 0A or less *
F0 = 30A or less *
Apply to IEC61000-3-3 about max. permissive system impedance.
*1 The Ground-fault interrupter should support inverter circuit.
The Ground-fault interrupter should combine using of local switch or wiring breaker.
* Please take the larger of F1 or F as the value for F0.
F1 = Total operating maximum current of the indoor units × 1.
F = {V1 × (Quantity of Type1)/C} + {V1 × (Quantity of Type)/C} + {V1 × (Quantity of Type3)/C} + {V1 × (Quantity of Others)/C}
Indoor unit
Type 1 SEZ-KD·NA, PLA-A·BA
Type  PEAD-A·AA
Type 3 MSZ-FE·NA
Type 4 MSZ-FH·NA, MSZ-GE·NA
Type 5 SLZ-KA·NA
Type 6 MFZ-KA·NA
Type 7 MVZ-A·AA
Type 8 Branch box (PAC-MKA·BC)
C : Multiple of tripping current at tripping time 0.01 s
Please pick up "C" from the tripping characteristic of the breaker.
<Example of "F2" calculation>
*Condition PEFY-VMS × 4 + PEFY-VMA × 1, C = 8 (refer to right sample chart)
F = 18.6 × 4/8 + 38 × 1/8
= 14.05
→ 16 A breaker (Tripping current = 8 × 16 A at 0.01 s)
**** Current sensitivity is calculated using the following formula.
G1 = V × (Quantity of Type1) + V × (Quantity of Type) + V × (Quantity of Type3) + V × (Quantity of Others)
+ V3 × (Wire length [km])
G1 Current sensitivity
30 or less 30 mA 0.1 sec or less
100 or less 100 mA 0.1 sec or less
Wire thickness

1.5 mm
.5 mm 

4.0 mm
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 or 2-pole type.
(Please refer to figure below.)
• Turn on the main power when the ambient temperature is -20°C (-4°F) or higher.
• Under conditions of -20°C (-4°F), it needs at least 4hr stand by before the units
operate in order to warm the electrical parts.
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.
Be sure to connect the outdoor-branch box/indoor-branch box connecting cables directly to the units (no intermediate connections).
Intermediate connections can lead to communication errors if water enters the cables and causes insufficient insulation to ground or a poor electrical contact at the intermediate connection point.
(If an intermediate connection is necessary, be sure to take measures to prevent water from entering the cables.)
Never splice the power cable or the indoor-outdoor connection cable, otherwise it may result in a smoke, a fire or communication failure.
14
Minimum Wire Thickness
Power Supply
Main Cable*
13.3 [AWG16] 13.3 [AWG16]
8.4 [AWG8]
Minimum wire thickness (mm
Main Cable Branch
.1/14 .1/14
3.3/1 3.3/1
5.5/10 5.5/10
V1
19.8
6.9
9.9
6.8
3.5
16.
6.9
5.1
V3
48
56
66
Breaker for
(mm [AWG])

Wiring*1
Ground
50 A
8.4 [AWG8] 40 A
Refer to installation manual of indoor unit.
/AWG)

Ground-fault interruper *1
Ground
.1/14 15 A current sensitivity *3
3.3/1 0 A current sensitivity *3
5.3/10 30 A current sensitivity *3
V
.4
3.0
B1
Outdoor unit
B2
Breaker for Current Minimum cir-
Leakage cuit ampacity
50 A 30 mA 0.1 sec.
4 A
or less
40 A 30 mA 0.1 sec.
37 A
or less
Local switch (A)
Capacity Fuse
15 15
0 0
30 30
Sample chart
6000
600
60
10
1
0.1
0.01
1 2 3
Rated Tripping current (x)
 poles isolator (Switch)
L1
L2
GR
Maximum rating of
over current protec-
tor device
5 A
5 A
Breaker for wiring
(NFB)
15
0
30
SAMPLE
4 6 8 10 20
C
Branch box