40
Specification of electric wire
10[A]
Indoor unit10
20[m]
10[m]
0[m]
9[A]
1[A]
100[m]
Indoor unit2
Indoor unit1
ELCB
or MCCB+
ELB
Rating current
Model
Rating
current
RHF050KHEA
1.7A
RHF100KHEA
3.7A
Power supply
MCCB
ELB or ELCB
Power cable
Earth cable
Communication cable
Max : 242V
Min : 198V
X A
X A, 30mmA
0.1 sec
2.5mm
2
2.5mm
2
0.75~1.5mm
2
Decide the capacity of ELCB(or MCCB+ELB) by below formula.
T
X : The capacity of ELCB(or MCCB+ELB).
T
∑Ai : Sum of Rating currents of each indoor unit.
T
Refer to each installation manual about the rating current of indoor unit.
D
ecide the power cable specification and maximum length within
10% power drop among indoor units.
Apply following equation.
Installing with one size cable.
Installing with two size cables.
Calculation
The capacity of ELCB(or MCCB+ELB) X [A] = 1.25 X 1.1 X ∑Ai
T
coef: 1.55
T
Lk: Distance among each indoor unit[m], Ak: Power cable specification[mm
2
]
ik: Running current of each unit[A]
∑ (
Coef×35.6×L
k
×i
k
) <
10% of input voltage[V]
1000×A
k
n
k=1
Example of Installation
- Total power cable length L = 100(m), Running current of each units 1[A]
- Total 10 indoor units were installed
∑ (
Coef×35.6×L
k
×i
k
) <
10% of input
voltage[V]
1000×A
k
n
k=1
220[V]
-2.2[V]
-2.0[V]
············ 2.5[mm
2
] ············
208.8[V](Within 198V~242V)
-(2.2+2.0+1.8+1.5+1.3+1.1+0.9+0.7+0.4+0.2)=-11.2[V]
it's okay
2.5[mm
2
]
2.5[mm
2
]
220[V]
-1.4[V]
-1.2[V]
············ 2.5[mm
2
] ············
209.5[V](Within 198V~242V)
-(1.4+1.2+1.8+1.5+1.3+1.1+0.9+0.7+0.4+0.2)=-10.5[V]
it's okay
4.0[mm
2
]
4.0[mm
2
]
Wiring work
RHF050KHEA_IB,IM_E_32885-3.indd 40
2011-10-12 오후 5:30:36
