Mitsubishi Electric CITY MULTI PKFY-P NLMU Series, Installation Manual, Page: 10 / 44

9
• V1 and V2
V1 and V2 are the breaker coefficient.
V1: Breaker coefficient of rated current
V2: Breaker coefficient of current sensitivity
The values of V1 and V2 differ from depending on the model. Therefore, please refer to IM of each model.
• 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 : PKFY-NLMU × 2 + PLFY-NEMU × 2 + PEFY-NMAU × 1
V1 of PKFY-NLMU = 19.8, V1 of PLFY-NEMU = 19.8, V1 of PEFY-NMAU = 38, C = 8 (refer to right sample chart)
F2 = 19.8 × 2/8 + 19.8 × 2/8 + 38 × 1/8
= 14.65
→ 15 A breaker (Tripping current = 8 × 15 A at 0.01 s)
*3 Current sensitivity is calculated using the following formula.
G1 = V2 × (Quantity of indoor unit 1) + V2 × (Quantity of indoor unit 2) + V2 × (Quantity of indoor unit 3)
+ ··· + V3 × (Wire length [km])
<Example of “G1” calculation>
*Condition : PKFY-NLMU × 2 + PLFY-NEMU × 2 + PEFY-NMAU × 1
V2 of PKFY-NLMU = 2.4, V2 of PLFY-NEMU = 2.4, V2 of PEFY-NMAU = 1.6, Wire thickness and length: 1.5 mm 2 (AWG14) 0.2 km
G1 = 2.4 × 2 + 2.4 × 2 + 1.6 × 1 + 48 × 0.2
= 20.8
As a result , current sensitivity is 30 mA 0.1 sec or less.
V1 V2
PKFY-NLMU 19.8 2.4
Fig. 6-2
C C C C C
A B
D
D
C
TB2 TB5 TB15
S 1 2 M1 L1 L2 M2
A B
~208/230 V
~208/230 V
6. Electrical work
6.2. Power supply wiring
• Wiring size must comply with the applicable local and national codes.
• Use copper supply wires.
Use UL wires rated 300 V or more for the power supply cords.
• Install a ground wire longer than other cables.
• A switch with at least 3 mm, 1/8 inch contact separation in each pole shall be
provided by the air conditioner installation.
[Fig. 6-2]
A Ground-fault interrupter
B Local switch/Wiring breaker
C
Indoor unit
D Pull box
Warning:
Never splice the power cable or the indoor-outdoor connection cable,
otherwise it may result in a smoke, a fire or communication failure.
Total operating current of the indoor
unit
Minimum wire thickness (mm²/AWG) Breaker for wiring
(NFB)
Ground-fault interrupter *1
Main cable Branch Ground Capacity Fuse
F0 = 15 A or less *2 2.1/14 2.1/14 2.1/14 15 15 15 15 A current sensitivity *3
F0 = 20 A or less *2 3.3/12 3.3/12 3.3/12 20 20 20 20 A current sensitivity *3
F0 = 30 A or less *2 5.3/10 5.3/10 5.3/10 30 30 30 30 A current sensitivity *3
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.
*2 Please take the larger of F1 or F2 as the value for F0.
F1 = Total operating maximum current of the indoor units × 1.2
F2 = {V1 × (Quantity of indoor unit 1)/C} + {V1 × (Quantity of indoor unit 2)/C} + {V1 × (Quantity of indoor unit 3)/C} + ···
6000
600
60
10
1
1 2 3 4 6 8
C
10 20
Sample chart
Tripping T
ime
[s]
Rated Tripping current (x)
0.1
0.01
SAMPLE
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 V3
1.5 mm
2
, AWG14 48
2.5 mm
2
, AWG13 56
4.0 mm 2 , AWG11 66
en
~ 208/230 V
Indoor
unit 1
Indoor
unit 1
Indoor
unit 2
Indoor
unit 3
Indoor
unit 3
RH79A034H02_en.indd 9 2019/12/16 9:54:26
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