What Is In Wall Speaker Wire? The Rated Line
Quick answer / TL;DR: In wall speaker wire is the speaker line rated for the concealed run: the two-conductor pair in the CMR jacket, the listing the wire carries for the in wall path, on the Class 2 circuit the low-voltage speaker line runs in. The CMR marking on the jacket is the figure that tells the rated wire from the general-purpose roll, and the rating is what lets the run go behind the drywall under the code's rules for the concealed circuit. The wire is the same speaker line at the same gauge, and the in wall figure is the jacket's rating, not the conductor's copper.
In wall speaker wire is the speaker line rated for the run the drywall covers: the same two conductors the standard speaker wire carries, in the jacket the concealed path is built to hold. The rating is the figure the question is after – the CMR marking on the jacket, the listing the wire carries for the in wall run, and the circuit class the wire's low voltage puts it in. The wire is the speaker line, and the in wall figure is the rating that lets it go behind the drywall the code's rules are written around.
This is the definition view: what the in wall rating is, the jacket marking that carries it, the circuit class the wire runs in, and the check that tells the rated wire from the roll that is not.
The Rating, and What It Is
The in wall rating is the jacket's figure, and the figure is the listing the wire carries for the concealed run. The standard speaker wire is the general-purpose stock – the two conductors in the jacket the open run takes, the wire the desk and the short path serve. The in wall wire is the same pair in the jacket rated for the path the drywall covers: the CMR marking, the communication wire listing for the riser and the master circuit, the fire rating the jacket's material carries for the enclosed cavity the run goes into. The rating is not the conductor's copper – the gauge is the same, the pair is the same – and it is the jacket's property, the one that lets the run go concealed under the code's rules for the circuit the speaker line occupies.
| The figure | The in wall wire | The general-purpose wire | What it decides |
|---|---|---|---|
| The jacket | The CMR, the rated listing | The general-purpose stock | The concealed run's allowance |
| The conductors | The two, the gauge the run holds | The same pair, the same gauge | The signal the line carries |
| The circuit | The Class 2, the low voltage | The Class 2, the same circuit | The protection the run is exempt from |
| The marking | The CMR on the jacket | The absent or the open-run figure | The check at the roll |
The table is the two wires against the four figures, and the reading is the rating's difference. The conductors and the circuit are the same – the pair at the gauge, the low-voltage line the Class 2 puts in – and the jacket and the marking are the figures that move. The CMR is the jacket's listing, the marking on the roll, and the concealed run's allowance is what the rating buys: the path behind the drywall the code's rules are written around, and the wire the listing lets into it.
The Jacket Marking, and How to Read It
The check is the jacket's print, and the figure it carries is the rating the run is built on. The CMR marking is the in wall stock – the communication master and riser listing, the wire rated for the enclosed path the building's cavity holds. The print runs along the jacket at the interval the listing sets, and the reading is the one that confirms the wire at the roll before the run goes into the wall. The general-purpose stock carries the absent marking or the open-run figure, and the check at the jacket's print is the minute that tells the rated wire from the roll that is not. The in wall wire is the one the print confirms, and the marking is the figure the install reads at the spool before the fish starts.
The listing behind the CMR
The CMR is the listing the wire carries, and the figure behind it is the standard the jacket is tested to – the communication wire's rating for the master and the riser circuit, the fire and the flame characteristics the jacket's material holds for the enclosed path. The listing is the test the wire passes, the marking is the proof it carries, and the in wall allowance is what the code gives to the wire that holds the listing. The CMR is the figure the concealed speaker run is built on, and the jacket's print is the one that states it at the interval the standard sets along the length.
The Circuit Class, and the Run It Puts In
The speaker line runs in the Class 2 circuit, and the figure is the one the wire's low voltage puts it in. The Class 2 is the power-limited circuit – the voltage and the power the speaker line carries below the figures that call for the protection the power circuit takes – and the classification is what exempts the run from the conduit and the overcurrent device the building wire needs. The in wall speaker wire is the line the Class 2 circuit runs, and the rating on the jacket is the figure that lets the circuit go concealed: the low voltage that keeps it in the class, and the CMR that rates it for the path. The two figures together – the circuit class and the jacket rating – are what the in wall speaker wire is, and the definition is the one the code's rules are written around.
Why the low voltage matters to the rating
The Class 2 classification is the figure the wire's voltage sets, and it is the one that makes the in wall run the exempt path. The speaker line carries the amplifier's output at the level below the class's figures, and the classification is what puts the run in the circuit the code's protection rules do not reach – no conduit, no breaker, the wire the jacket's rating alone qualifies for the concealed path. The in wall speaker wire is the low-voltage line in the rated jacket, and the definition's two halves – the circuit and the jacket – are the ones the low voltage makes possible together.
In wall speaker wire is stocked as the CMR-rated line in the gauge range, the jacket's print at the listing's interval, solid and stranded; the catalog lists the gauge, the conductor count, the jacket rating and the length per roll.
Real-World Applications
The install that checked the roll at the spool: the CMR print along the jacket, the rating confirmed before the fish, the run that went into the wall on the wire the listing qualified. The retrofit that found the general-purpose stock in the pre-wired house: the jacket's absent marking, the check that told the open-run wire from the concealed-rated line, and the replacement the rating the wall's cavity called for. The builder's rough-in at the new construction: the CMR stock on the spool in the stud bay, the circuit class the low voltage held, the listing the jacket's print carried down each run the drywall was about to cover. In each the in wall speaker wire is the rated line – the jacket's figure, the circuit's class, and the marking the roll's print confirms at the minute that tells it from the wire that is not.
Related reading: The rated line against the open-run stock: in wall speaker wire vs regular — in-wall-speaker-wire-vs-regular
Related reading: The rules the rating runs under: speaker wire in wall code — speaker-wire-in-wall-code
Frequently Asked Questions
What is in wall speaker wire?
The speaker line rated for the concealed run: the two-conductor pair in the CMR jacket, the listing the wire carries for the in wall path, on the Class 2 circuit the low-voltage speaker line runs in. The rating is the jacket's figure, not the conductor's – the same copper at the same gauge as the general-purpose wire, in the jacket the listing qualifies for the path behind the drywall.
What does CMR mean on speaker wire?
The communication wire listing for the master and riser circuit – the rating the jacket carries for the enclosed path the building's cavity holds. The CMR marking runs along the jacket at the interval the standard sets, and it is the figure that tells the in wall rated wire from the general-purpose roll. The check is the print at the spool, and the in wall allowance is what the listing buys for the concealed run.
Is in wall speaker wire different from regular speaker wire?
The jacket, not the copper. The conductors are the same pair at the same gauge, and the circuit is the same Class 2 the low voltage puts it in. The difference is the jacket's rating – the CMR listing the in wall wire carries against the general-purpose stock's open-run figure – and it is the figure that lets the run go behind the drywall under the code's rules for the concealed circuit.
How do I know my speaker wire is rated for in wall use?
Read the jacket's print. The CMR marking along the jacket is the in wall rating – the communication wire listing for the enclosed path – and the check at the roll before the fish is the minute that confirms it. The general-purpose stock carries the absent marking or the open-run figure, and the wire without the CMR print is the one that stays on the open run rather than the concealed path the wall covers.
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