HOW bad is it to use electricians holes for speakers? (1 Viewer)

[Jimmy vb]

I am having a new family room built and I am running the in wall speaker wires. I am doing this on a budget. I bought jacketed in wall approved cable for the surrounds with wall plates. The electrician is about to do rough in. I could drill separate holes for my speakers and I know that is probably the right thing to do but I get different advice from different folks. What kind of problems would I run into if I ran the speaker cable through the same holes as the electrical cable? This would save some hassle on my end and the construction schedule is keeping everything very tight timing wise. All of the cables are insulated.

 

[Leo Kerr]

Speaker cable is less succeptable to AC hum than, say, signal wires. That, however, is no guarantee.

A word of advice, in many building codes, for every hole going through the studs to carry cables, you'll need a metal plate on the stud to protect against nail-strikes. Even if they are signal wires. Not hard or expensive; just probably needs to be done before your inspector comes out...

Leo Kerr

 

[ClintS]

I would not run the speaker cable parallel to power lines. Yes it might work but why risk it? Take the time to do it right and then you will never have to wonder if you system could have sounded better. It is okay to cross at a 90 degree angle also generally try to keep at least a foot in between any parallel runs. In my house all the electrical was down low, I ran all the speaker wire up high acroos the ceiling. A decent drill with a spade bit will make a hole in less than 10 seconds it really isnt hard if you have the right equipment.

 

[Hank Frankenberg]

...very painful for the electrician

Seriously, Clint is correct - don't run signal wires parallel to AC power wires.

 

[Dave Milne]

Yeah,
One could actually calculate the signal amplitude that would be capacitvely and inductively coupled onto the speaker cable knowing the current in the AC line, the spacing between the wires, the length of run that they are together, the speaker impedance, etc. At 60 Hz and with reasonable distances (say tens of feet), I think capacitive coupling will be negligible. You're probably more likely to couple high-frequency AC noise from the power line. Inductive coupling might be more significant, but I'm too lazy to try and run some sample calculations.

It's probably easier to drill a few more holes than wrestle with the math.

Incidentally, Leo... last time I checked NEC codes, nail plates are only required if the wires are within 1.5 inches of the stud face. Thus, if you drill a 1/2"-ish hole in the middle of the stud and pull one or two runs of Romex through it, no plate required. If you drill a big hole for a wad of cables... or if you need to offset the hole toward the stud face for some reason... you need the plate. And I don't think nail plates are required for any low-voltage / signal cables. Ask your electrician, he/she should know the local codes.

 

[Leo Kerr]

I know people who've been bitten in this area.. maybe the inspectors didn't know the real code or what, but some people have essentially been told: if it goes through the stud, it needs a nail-plate.

The one exception was flexible 'greenfield' going through metal studs...

Leo Kerr

 

[Jimmy vb]

Points well taken--I am going to go through a separate track than the ac power. The electrician is going to drill the holes for me to save me getting a right angle drill and I'll run the rest.