2. Cable size
The thickness of the cables in the circuits (branch circuits) providing the main power supply to
each item of apparatus must satisfy the following conditions:
1. To have a current tolerance of 40% or more of the rated current of the overcurrent circuit
2. To have a current tolerance of 125% or more of the rated current in cases where the rated
3. To have a current tolerance of 110% or more of the rated current in cases where the rated
4. To satisfy voltage drop standards.
3. Separation of control and power supply cables
! If control and power cables are run alongside each other then there is a strong likelihood
1. The figures are based on an assumed length of parallel cabling up to 100m. For lengths in
2. If the power supply waveform continues to exhibit some distortion the recommended
If the cables are laid inside conduits then the following points must also be taken into account
when grouping various cables together for introduction into the conduits.
1. Power cables (including power supply to the air conditioner) and signal cables must not be
2. In the same way, when grouping the cables, power and signal cables should not be bunched
! Important points
! Have the indoor and outdoor units both been earthed?
∗ If the apparatus is not properly earthed then there is always a risk of electric shocks. The
breaker (wiring circuit breaker, etc.).
current of the apparatus is 50A or less.
current of the apparatus is more than 50A.
of operational faults developing due to interference in the signal wiring caused by
electrostatic and electromagnetic coupling.
The table below indicates our recommendations as to the appropriate spacing of control and
power cables where these are to be run side by side.
Current capacity of power cable
100V or more
excess of 100m the figures will have to be recalculated in direct proportion to the additional
length of cable involved.
spacing in the table should be increased.
laid inside the same conduit. (Power cables and signal cables must each have their own
earthing of the apparatus must be carried out by a qualified person.
10A or less
100A or more