Which speaker cable should I use?
Which speaker cable should I use?
16 AWG for short runs and 14 AWG beyond about 15 metres or into low-impedance speakers — and make sure it is copper, not copper-clad aluminium.
Speaker cable is a resistor in series with the speaker, and the useful rule of thumb is to keep the cable's total resistance below about 5% of the speaker impedance — so an 8-ohm speaker tolerates roughly 0.4 ohms of cable, and a 4-ohm speaker only half that. That is what sets the gauge, along with the run length, and once the cable is comfortably inside that limit, nothing further is gained: the differences claimed for exotic cables at domestic lengths are not supported by measurement. Where money genuinely matters is in the basics — actual copper rather than copper-clad aluminium, a sound mechanical termination, and a cable rated for in-wall use if it is going in a wall.
The options, ranked
| Option | Good at | Bad at |
|---|---|---|
| 16 AWG (1.5 mm²) copper | More than adequate for typical domestic runs and easy to terminate. | Resistance becomes significant on long runs into 4-ohm speakers. |
| 14 AWG (2.5 mm²) copper | The safe default for long runs, in-wall installs and low-impedance loads. | Stiffer, more expensive, and unnecessary for a short run. |
| In-wall rated cable | Required by building codes for permanent installation because of its fire performance. | Costs more; check the marking rather than the description. |
| Copper-clad aluminium (CCA) | Cheap and light. | Roughly 60% of copper's conductivity, corrodes at terminations, and is often sold without being obvious about it. |
Technique that changes the outcome
- Measure the run and choose the gauge from length and speaker impedance
- Keep both channels the same length so nothing is imbalanced, and keep polarity consistent
- Terminate with banana plugs or properly crimped spades rather than bare twisted strands
- Use in-wall rated cable for permanent installation
What goes wrong
- Copper-clad aluminium sold as copper
- Bare stray strands bridging the terminals, which can short an amplifier output
- Running speaker cable alongside mains cable for long parallel distances
Compiled practical guidance rather than a published standard. Product formulations vary by brand and market, so read the label — and where the work is structural, electrical or gas, the regulations that apply where you are govern rather than anything here.
Other cable and wire questions
| For | Use |
|---|---|
| Extension leads | One with a conductor rated for the full load, and always fully unwound — a coiled cable reel can be derated to a fraction of its rating. |
| A socket circuit | Typically 2.5 mm² for a UK ring final on a 32 A device, or 12 AWG on a US 20 A branch circuit — subject to the code and the installation method. |
| 12 V DC and automotive | Size it for voltage drop, not current — at 12 V a small drop is a large percentage, so the cable is far thicker than the amps suggest. |
| A lighting circuit | Typically 1.0 or 1.5 mm² twin and earth in the UK, or 14 AWG on a 15 A circuit in the US — but the code and the installation method decide. |
| Outdoor and buried runs | Steel wire armoured cable, or a direct-burial type, at the required depth with RCD or GFCI protection — never ordinary indoor cable. |
| An electric shower | Commonly 6 or 10 mm² depending on the shower rating, the run length and the installation method — and it is notifiable work in most jurisdictions. |
Common questions
- Which speaker cable should I use?
- 16 AWG for short runs and 14 AWG beyond about 15 metres or into low-impedance speakers — and make sure it is copper, not copper-clad aluminium.
- What should I avoid?
- Copper-clad aluminium sold as copper Bare stray strands bridging the terminals, which can short an amplifier output Running speaker cable alongside mains cable for long parallel distances
Related pages
- Which extension lead should I use for a heavy load? One with a conductor rated for the full load, and always fully unwound — a coiled cable reel can be derated to a fraction of its rating.
- Which cable size is used for socket circuits? Typically 2.5 mm² for a UK ring final on a 32 A device, or 12 AWG on a US 20 A branch circuit — subject to the code and the installation method.
- Which wire size should I use for a 12 V circuit? Size it for voltage drop, not current — at 12 V a small drop is a large percentage, so the cable is far thicker than the amps suggest.
- Which cable size is used for a lighting circuit? Typically 1.0 or 1.5 mm² twin and earth in the UK, or 14 AWG on a 15 A circuit in the US — but the code and the installation method decide.
- Which cable should I use outdoors or underground? Steel wire armoured cable, or a direct-burial type, at the required depth with RCD or GFCI protection — never ordinary indoor cable.
- Which cable size does an electric shower need? Commonly 6 or 10 mm² depending on the shower rating, the run length and the installation method — and it is notifiable work in most jurisdictions.
Sources
- Typical range compiled from manufacturer specifications — At One Place