Running speaker cable near high voltage wire

[ilnoca]

I'm going under the house this coming weekend to run the cable for my rear speakers and sub. To minimize the holes I'm thinking of using a hole that that was drilled to bring up Romex and a coax line for cable service. The coax isn't in use any longer, but I'll run a new coax line from my receiver to that location for my sub. I've done my fair share of data wiring but this will be my first time running speaker wire in a structured wiring setup.

I'm concerned the high voltage line will distort the signal run over speaker cables for the six or so inches they are run in parallel; I know this would be a problem running UTP for data. Is this a legitimate concern or would the audible range not be affected enough to be noticeable?

Thanks,

Sam

 

[TLS Guy]

Hard to know

It would be best if the speaker wires and he coax were in steel conduit. If you can't do that, you may get away with it. On the other hand the AC cables may induce 60 Hz in the speaker cables. The speaker cables will return this induced signal to the amp. The negative feedback circuit of the amp, may well feed this back through the high gain circuits, and it will be amplified as an audible 60 Hz buzz.

 

[Swerd]

I'm going under the house this coming weekend to run the cable for my rear speakers and sub. To minimize the holes I'm thinking of using a hole that that was drilled to bring up Romex and a coax line for cable service. The coax isn't in use any longer, but I'll run a new coax line from my receiver to that location for my sub. I've done my fair share of data wiring but this will be my first time running speaker wire in a structured wiring setup.

I'm concerned the high voltage line will distort the signal run over speaker cables for the six or so inches they are run in parallel; I know this would be a problem running UTP for data. Is this a legitimate concern or would the audible range not be affected enough to be noticeable?

Is the high voltage line carrying 15 amps, 115 volts AC at 60 Hz? If the cable for the rear speakers is unsheilded 2 conductor wire, it very well may pick up a 60 Hz hum from the power line. If your subwoofer is actively amplified, the coax for it is shielded, but it will carry a lower voltage pre-amp level signal that may also pickup interference from running parallel to the power line. And when amplified through a subwoofer, that 60 Hz tone will be loud.

I would keep those cables away from any AC power line. If they must cross a power line, keep them at a 90° angle.

 

[mtrycrafts]

I'm going under the house this coming weekend to run the cable for my rear speakers and sub. To minimize the holes I'm thinking of using a hole that that was drilled to bring up Romex and a coax line for cable service. The coax isn't in use any longer, but I'll run a new coax line from my receiver to that location for my sub. I've done my fair share of data wiring but this will be my first time running speaker wire in a structured wiring setup.

I'm concerned the high voltage line will distort the signal run over speaker cables for the six or so inches they are run in parallel; I know this would be a problem running UTP for data. Is this a legitimate concern or would the audible range not be affected enough to be noticeable?

Thanks,

Sam

Use twisted speaker cable for the speakers and well shielded coax for the sub input. Try to minimize the parallel run and turn it 90 degrees as quickly as you can and put some distance between them.

 

[Rickster71]

Go with your first instinct; you wouldn't run data lines there, don't run your speaker wires in the same hole either.
If it were me, I'd drill a new hole.
If you end up with noise, you'll have to do it all over.

 

[jake5717]

Here's a really stupid question! What would happen if you just got some foil and used that to seperate the wires for the 6"?

 

[ilnoca]

Thanks for confirming my suspicions on this one. Since it's only a 3/4" hole, using conduit is out of the question, and I don't think foil would survive the pull intact. One more hole shouldn't be a problem.

 

[Rickster71]

Here's a really stupid question! What would happen if you just got some foil and used that to seperate the wires for the 6"?

It's not just that.
It's also a code issue.

The NEC's rational is, there is less of a chance the low voltage wires becoming energized if they are kept separate from AC line voltage.
They can share the same box as long as it's approved, or has an approved divider.