Outdoor Panel-To-Panel Wiring; Wiring Precautions - YASKAWA MP920 User Manual

D.3

Outdoor Panel-to-Panel Wiring

D.3.1

Wiring Precautions

The procedure for laying communications cables is based on the procedure described in
Indoor Panel-to-Panel Wiring
• For outdoor wiring, always lay the communications cables along an above-ground struc-
• Where there is no above-ground structure, house the communications cables in an under-
• Do not lay bare communications cables overhead. Otherwise, the cables will collect
• The transmission system is not protected against lightning surge. If the communications
• Communications cables expand according to the surrounding temperature. Generally, the
• If the communications cables are housed in a metal wiring conduit or duct, water will be
, but heed the following precautions.
ture such as steel frames (see Fig. D.11 (a) below).
ground pit or tunnel, or bury them in the ground (see Fig. D.11 (b) and (c) below).
inductive noise from electric waves in the air and cause transmission errors.
cables are laid overhead, the equipment may be damaged due to lightening.
temperature coefficient of communications cables is approximately 0.05% per 10°C.
For example, a 500-meter communications cable expands 25 cm when the temperature
increases 10°C. Normally, this amount of expansion can be absorbed within the cabling
route. However, where communications cables are laid along above-ground structure, the
temperature difference will be considerably large and cable expansion or contraction
may not be absorbed within the cabling route. To prevent this, the communications
cables must be given some play so that their expansion and contraction can be absorbed
within the route.
trapped inside the conduit or duct and apply mechanical stress to the communications
cables when frozen in winter. To prevent this, provide the conduit or duct with drain
holes.
D-17
D.3 Outdoor Panel-to-Panel Wiring
D.2
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