[low.pfile]

I know nothing about inwall wiring and cabling. but am giving some basic guidance to a friend doing a den remodel, otherwise she would have to depend solely on her contractor. I've mostly pointed out  the number/type of cables for speakers and component connections and wall plates.

I was there tonight and the contractor has already installed the blue boxes for speaker wall plates (one left and one right). BUT I noticed that they were the double wide type (i.e. double-gang J-box ) and she said the contractor was planning to use a dual face plate: one for the speaker channel and one for AC power outlet all in the same j-box. That was a surprise. I had suggested that the wall plate be just for speakers. And there would be a separate location for the power outlet.

So my question is will there be any interference/static/hum due to this AC power /speaker wire combo set up?  My gut says YES, but I have no basis for this. I am not expecting the contractor to be an audio specialist but have down the basics. 

This inwall speaker cabling is just for a basic stereo music system with older towers (ADS from the 90s?) and a 2 channel receiver so nothing high end here. I just want to make sure she is not going to get hum on the line. The speaker cable will be CL2 rated (it is not installed yet but the power seems to be almost wired up.)  The source audio components will be on the opposite wall from the speakers, in a separate built in shelf.

I know many of you guys do this stuff with your eyes closed and can provide the suggested method.

Thanks,
Ed

mods: please move if needed. I thought there was a HT Build/ forum but couldn't find it.

[Wayner]

I believe this is a violation of the NEC. Unless he is going to put a divider "barrier" between the 2 gang boxes, isolating each individual gang, if you will. Hopefully, the wires aren't in the same conduit (if conduit is a building code requirement where you are). I wouldn't really worry about electrical interference, I'd worry about speaker wires contacting outlet wires......boom!

Wayner 

[Big Red Machine]

Fire that guy.  He is only making his life easier with fewer boxes.

Never mix the two for safety and NOISE!!!!

You'll love the 60 hz hum through your speakers, oh yeah!

[low.pfile]

Thank you very much guys!
btw this is in California

Ed



EDIT 01/25/09:
The contractor is revising the install to have separate boxes. His orig plan was a divider within the box.
Thanks again for your insight.

[CSI]

FWIW

Noise issues aside, running high and low voltage through the same conduit and/or into the same J-Box is dangerous! No custom installer worth hiring would dream of it and even the lamest licensed electrician would be appalled. A divider would make it safer but I wouldn't let a guy who didn't know better near my home (and neither would my insurance agent).

Custom installers (low voltage guys) are taught to never run audio cables through the same holes in framing as high voltage wires. The proper practice is to drill your own holes, keep them at least a foot away from power lines, and cross at 90 degree angles whenever possible.

I'm glad the contractor came to his senses but, if it were my place, he'd be off the job.