3. Cabling
3-3
TI 30A30A10-01EN
CAUTION
• Power cables must be laid 1 cm or further away from signal cables.
• Power and grounding cable are use power and grounding cables which are in conformance
with the safety standard of each country.
n
Type and maximum length of power cables
Formulas are given below for determining the type and the maximum length (m) of branch cables
from an indoor low-voltage main line.
• The standard type of cable used (nominal cross sectional area) is equivalent to JIS C 3312.
• Calculate the maximum power cable length from the following conditions in Figure.
However, the power cable must meet the conditions described in Section “1.2 Power supply
system”, “AC Power specification”.
Low-voltage
wiring
Power distribution
board
Equivalent voltage drop (referred to 100 V
supply) of 2 V or less in the main line, viewed
from the indoor power distribution board
Voltage drop of 2 V or less
across this section of wiring
Equip-
ment
L (m)
AC wiring (100 V AC, 220 V AC)
High-voltage
wiring
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Figure Maximum cable length calculation conditions
[Maximum power cable length calculation conditions]
Use the following formula to calculate the maximum power cable length:
• 100 V AC and 220 V AC supply voltages
F030203.ai
L (m)=
Voltage drop across wiring
Conductor resistance (Ω/km)×(Number of cores)×Equipment current consumption
× 1000
Note: In the formulas above, the voltage drop across wiring is assumed to be 2 V for AC power supplies ; the number of cores is two;
and the conductor resistance is as specified in the table below.
Table Wire nominal cross sectional areas and resistances
Wire nominal cross sectional area
5.5 mm
2
8 mm
2
14 mm
2
22 mm
2
Wire conductor resistance
3.37 Ω/km
2.39 Ω/km
1.36 Ω/km
0.82 Ω/km
Feb. 26, 2018-00
