Quick Answer / Summary: For concealed home runs: CL2/CL3 rated cable (CL3P in plenums), 14 AWG for most rooms up to 20 m, 12 AWG for long runs or 4 ohm loads, plates with binding posts or speakON at each end, and conduit wherever the route allows. Keep runs away from mains, photograph the route, and label both ends. Buy one batch so a future repair matches.
In a house, the cable goes in before the walls close and stays for decades. The decisions that matter are rating, route and termination – not brand. This guide covers the install side of a home amplifier and speaker system.
Rating and Route
In-wall cable must carry a CL rating: CL2 for residential, CL3 for commercial, CL3P for plenum spaces where air circulates. The rating covers jacket flammability, and an inspector will check it. Route: inside stud bays, through conduit where possible, and never across ceiling joists where a future fixing will find it. Separation from mains: 300 mm minimum where parallel, with right-angle crossings. Photograph every wall before the drywall closes – the images are worth more than any drawing.
Conduit Is Cheap Insurance
A 20 mm conduit to each speaker position lets the cable be replaced without opening the wall. Install it before the board goes on.
Separation From Mains
Keep 300 mm where parallel and cross at right angles. Induced hum is a routing problem, not a cable-quality problem.
Gauge for Multi-Room Runs
A multi-room amplifier may sit in a cupboard with runs of 10-30 m to each room. At 8 ohm and 20 m, 14 AWG keeps loop resistance at 0.53 ohm – under 7% of the load. For 30 m or 4 ohm speakers, 12 AWG. Multi-zone systems often parallel two rooms on one channel: calculate the combined impedance before choosing gauge, because the current doubles when the load halves. Where a room’s speakers are in series (rare), impedance rises and gauge can be thinner – but damping suffers.
Cupboard Reality
A central cupboard adds 10-20 m to every run. Size for the longest, not the average.
Zone Paralleling
Two 8 ohm rooms on one channel is 4 ohm. Confirm the amplifier’s rating and step up a gauge.
Termination and Testing
Wall plates: binding posts for consumer systems, speakON for higher power, and a plate that accepts the cable’s gauge without cutting strands. Terminate with enough slack to re-make the connection once, label both ends with the room name, and test continuity and polarity per run before the amplifier is connected. In a multi-room system, a single reversed room is hard to diagnose by ear – a meter finds it in seconds.
Plate Choice
Binding posts for domestic systems; speakON where power or tamper-resistance matters. Both need space behind the plate for the bend.
Test Per Room
Continuity and polarity room by room, logged. The log becomes the system’s wiring diagram.
Home Run Spec
| Parameter | Value | Note |
|---|---|---|
| Rating | CL2 / CL3 | CL3P in plenums |
| Gauge | 14 AWG to 20 m | 12 AWG beyond |
| Separation | 300 mm from mains | Right-angle crossings |
| Plates | Binding post or speakON | Space for bend |
| Labels | Room name, both ends | Test log kept |
Real-World Application Scenarios
A four-room system runs 14 AWG from a central cupboard, longest run 22 m, all CL2 in conduit with plates. A living room with 4 ohm floorstanders uses 12 AWG for its 12 m run. A retrofit uses surface trunking where the wall cannot be opened, with the same gauge and rating discipline.
Recommended Internal Resources
(1) Product cluster – https://zh-zong.com/productlist/ (anchor: in-wall CL2/CL3 speaker cable); (2) FAQ – https://zh-zong.com/faq/ (anchor: rating and routing questions); (3) Contact – https://zh-zong.com/contact/ (anchor: request a multi-room schedule).
Related Reading in This Series
- Amplifier for Sound System: Rack Wiring and Cable Discipline
- Amp Speaker System: The Cable Plan for a Multi-Speaker Rig
- Wireless Stereo Amplifier: What Still Needs a Cable
Frequently Asked Questions (FAQ)
Q: What cable rating for in-wall speaker runs?
A: CL2 or CL3 for concealed runs, CL3P in plenum spaces. It is a code requirement and inspectors check the jacket print.
Q: What gauge for a 25 m run?
A: 14 AWG at 8 ohm keeps loss reasonable; step to 12 AWG for 4 ohm loads or runs beyond 30 m.
Q: Can two rooms share one amplifier channel?
A: Only if the combined impedance stays within the amplifier’s rating. Two 8 ohm rooms in parallel is 4 ohm – confirm the rating and size the cable for double current.