Installation Si39-303
54 General Information
Note:
The rated current for package air conditioners which use special purpose built-in compressor motors in
their compressors in 1.2 times the operating current shown on the name plate.
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 breaker (wiring
circuit breaker, etc.).
2. To have a current tolerance of 125% or more of the rated current in cases where the rated current of the
apparatus is 50A or less.
3. To have a current tolerance of 110% or more of the rated current in cases where the rated current of the
apparatus is more than 50A.
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 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.
Notes:
1. The figures are based on an assumed length of parallel cabling up to 100m. For lengths in excess of
100m the figures will have to be recalculated in direct proportion to the additional length of cable
involved.
2. If the power supply waveform continues to exhibit some distortion the recommended spacing in the
table should be increased.
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 laid inside
the same conduit. (Power cables and signal cables must each have their own individual conduits.)
2. In the same way, when grouping the cables, power and signal cables should not be bunched together.
!
Important points
1. Earthing
!
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 earthing of the
apparatus must be carried out by a qualified person.
Current capacity of power cable Spacing (d)
100V or more
10A or less 300mm
50A 500mm
100A 1000mm
100A or more 1500mm
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