Audio
Speaker wire is used to make the electrical connection between loudspeakers and audio amplifiers. Modern speaker wire consists of two or more electrical conductors individually insulated by plastic (such as PVC, PE or Teflon) or, less commonly, rubber. The two wires are electrically identical, but are marked to identify the correct audio signal polarity. Most commonly, speaker wire comes in the form of zip cord.
Wire gauge
Thicker wires reduce resistance. The resistance of 16-gauge or heavier speaker connection cable has no detectable effect in runs of 50 feet (15 meters) or less in standard domestic loudspeaker connections for a typical 8 ohm speaker. As speaker impedance drops, lower gauge (heavier) wire is needed to prevent degradation to damping factor – a measure of the amplifier's control over the position of the voice coil.
Most consumer applications use two conductor wire. A common rule of thumb is that the resistance of the speaker wire should not exceed 5 percent of the rated impedance of the system. The table below shows recommended lengths based on this guideline:
| Wire size | 2 Ω load | 4 Ω load | 6 Ω load | 8 Ω load |
|---|---|---|---|---|
| 22 AWG (0.326 mm2) | 3 ft (0.9 m) | 6 ft (1.8 m) | 9 ft (2.7 m) | 12 ft (3.6 m) |
| 20 AWG (0.518 mm2) | 5 ft (1.5 m) | 10 ft (3 m) | 15 ft (4.5 m) | 20 ft (6 m) |
| 18 AWG (0.823 mm2) | 8 ft (2.4 m) | 16 ft (4.9 m) | 24 ft (7.3 m) | 32 ft (9.7 m) |
| 16 AWG (1.31 mm2) | 12 ft (3.6 m) | 24 ft (7.3 m) | 36 ft (11 m) | 48 ft (15 m) |
| 14 AWG (2.08 mm2) | 20 ft (6.1 m) | 40 ft (12 m) | 60 ft (18 m)* | 80 ft (24 m)* |
| 12 AWG (3.31 mm2) | 30 ft (9.1 m) | 60 ft (18 m)* | 90 ft (27 m)* | 120 ft (36 m)* |
| 10 AWG (5.26 mm2) | 50 ft (15 m) | 100 ft (30 m)* | 150 ft (46 m)* | 200 ft (61 m)* |
* While in theory heavier wire can have longer runs, recommended household audio lengths should not exceed 50 feet (15 m).