MEDEA Installation Manual
39
The formula for calculating the voltage drop is
V = 2 x length x R
cond
x I
disp
where:
V
is the voltage drop in volts
length
is the length of the cable (single conductor) in metres
R
cond
is the resistance of the conductor in ohm/m
I
disp
is the maximum current consumption of all devices powered by that cable, in amperes
(the value can be found in the respective data sheets)
The resistance values of copper conductors are:
Cross-section area in
mm
2
0.22
0.50
0.75
1.00
1.50
Resistance in Ohm/m
0.0795 0.0350 0.0233 0.0175 0.0117
Table 27 - Resistance of copper conductors
IMPORTANT
The regulations require that the conductor cross-section area must not be less than
0.1 mm
2
.
In case of a complex power network with several branches, the calculation must be carried out for each
individual section.
For example, the maximum possible cable lengths for various cross-section areas are given as a function
of the maximum current flowing through the conductors.
Current I
Cross-section area
0.22 mm
2
0.50 mm
2
0.75 mm
2
1 mm
2
1.5 mm
2
0.300 A
31 m
71 m
107 m
143 m
214 m
0.500 A
19 m
43 m
64 m
86 m
129 m
0.750 A
13 m
29 m
43 m
57 m
86 m
1.000 A
9 m
21 m
32 m
43 m
64 m
1.500 A
6 m
14 m
21 m
29 m
43 m
2.000 A
5 m
11 m
16 m
21 m
32 m
2.500 A
4 m
9 m
13 m
17 m
26 m
3.000 A
3 m
7 m
11 m
14 m
21 m
Table 28 - Maximum power cable length
Содержание MEDEA
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