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.

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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