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Wire Diameters For Your Loudspeakers

These are our recommendations for copper or silver wire diameters.
 
Length of
copper wires
in metres
0 - 1 1 - 2 2 - 3 3 - 4 4 - 5 5 - 6 6 - 7 7 - 8.5
Output at / Ohm loudspeakers Required wire diameter in mm2
0-100 W / 4 Ohm 1.5 1.5 1.5 2.5 2.5 2.5 4 4
0-100 W / 2 Ohm 1.5 2.5 2.5 4 4 4 6 6
100-400 W / 4 Ohm 2.5 2.5 2.5 2.5 4 4 4 4
100-400 W / 2 Ohm 2.5 2.5 2.5 4 4 4 6 6
400-800 W / 4 Ohm 2.5 2.5 2.5 2.5 4 4 4 4
400-800 W / 2 Ohm 2.5 2.5 2.5 4 4 4 6 6
800-1600 W / 4 Ohm 2.5 2.5 4 4 4 4 4 4
800-1600 W / 2 Ohm 4 4 4 4 4 6 6 6

If the wire diameters seem to small to you, here is a calculation:

Let's assume that your speakers have a resistance of 2 Ohm and your amp has an output of 1600 Watts (that's the most demanding scenario in the table above). Calculation of maximum current:

I = square root(P/R) = square root(1600 W / 2 =ohm) = square root(800 W/Ohm) = 18 A

According to the DIN table below a wire of 2.5 mm2 diameter is almost sufficient; however, voltage drop and damping also has to be considered.

A copper wire of 8.5 metre length (to be precise it's length is 17 metres, there and back) with 4 mm2 diameter has a resistance of 0.048 Ohm. This means you are giving away almost 2.5 % power and the damping factor is 40.

DIN VDE 0298, Part 2

The following table indicates the maximum current load for a pair of copper wires according to DIN VDE 0298, part 2, laid in air. We believe that this table works well a guideline.
 
Size Data according to DIN VDE 0298, part 2 for 2-wire conductor in air
Wire diameter in mm2 1.5 2.5 4 6 10 16 25 35 50 70 95
maximum current in A 20 27 37 48 66 89 118 145 176 224 271

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