Lighting & Signalling modules
9
Site: exxotest.com
Table of standard values for electrical conductors:
Conductor
Resistivity in Ω.m
Silver
1,64 .10
-8
Copper
1,72 .10
-8
Aluminium
2,69 .10
-8
Nickel
7,8 .10
-8
Iron
9,8 .10
-8
Chrome-plated nickel
108,5 .10
-8
Table showing resistance and weight of copper wiring:
Diameter
mm
Cross section
mm
2
Weight
kg/km
Weight
kg/km
1,00
0,7854
7
22,28
1,50
1,7671
15,750
9,903
2
3,142
28,00
5,570
2,5
4,909
43,75
3,565
3
7,069
63
2,476
Fuse
A fuse is a safety device, used to protect an electrical circuit from excess current. Generally, fuses
comprise a metal strip which melts at a given temperature. If the current flowing through the circuit
exceeds a pre-determined value, the fuse metal melts, thus opening the circuit.
A 10A fuse is designed to withstand 10 Amperes at 20°C; however, it will withstand 20A for a period of
10 seconds, 30A for 5 seconds and even 80A for 0.01 seconds.
Here is an example of the time/current curve for a fast blow 10A fuse (time-delayed fuses are also
available).
Example of a graph:
Example of curve:
1
10
3
10
2
10
1
10
-2
10
-3
10
-1
10
100
1
A
T (s)
