Your Universal Remote Control Center
RemoteCentral.com
Custom Installers' Lounge Forum - View Post
Previous section Next section Up level
Up level
The following page was printed from RemoteCentral.com:

Login:
Pass:
 
 

Topic:
120v and speaker wire behind crown moulding.
This thread has 14 replies. Displaying all posts.
Post 1 made on Saturday July 26, 2014 at 22:18
Craig Aguiar-Winter
Senior Member
Joined:
Posts:
September 2002
1,489
A client is having crown moulding installed in order to hide wire for lights they are having installed. I would like to use this opportunity to run some speaker wire for a couple of speakers. I was always taught to run low voltage 18" apart from parallel runs of high voltage. Is this as much of an issue with speaker wire? Does code even allow this to happen?

Craig
My wife says I can't do sarcasm. She says I just sound like an a$$hole.
Post 2 made on Saturday July 26, 2014 at 22:36
Ernie Gilman
Yes, That Ernie!
Joined:
Posts:
December 2001
30,104
You presumably mean Romex for power, yes?

I can't speak to code on this. The code issue is always safety, so let's think. If the Romex got too hot... then the breaker should have blown. If the Romex and the speaker wire both scraped across some metal and shorted together... then you would have put up some pretty strange crown molding. If the speaker wire gets too hot, the amp should have already shut down. The only practical safety problem I can envision is them shorting together during a fire, at which time, well, there will already be a fire!

As for running them parallel, yeah, they should be separated; but for best performance, use 14-4; look at the end and count the wires around the circle as 1, 2, 3, 4; use 1 and 3 for hot and 2 and 4 for ground, or the other way around if the color code makes more sense that way; that'll give you the best-balanced wiring. Look at a length of speaker wire with the jacket off so you know about how many twists it has per, say, five feet; twist the Romex a bit more or a bit less than that. I've never recommended this, but hey, it will balance the magnetic fields around the Romex. The worst would be Romex mounted flat with untwisted speaker wire on top of it!
A good answer is easier with a clear question giving the make and model of everything.
"The biggest problem in communication is the illusion that it has taken place." -- G. “Bernie” Shaw
OP | Post 3 made on Saturday July 26, 2014 at 23:30
Craig Aguiar-Winter
Senior Member
Joined:
Posts:
September 2002
1,489
I won't be doing the electrical but I imagine the electrician will use armoured cable to avoid any miss fired nails puncturing it. If this is the case and I can't twist it is this install doomed?

All four walls will get moulding. I don't see why we won't be able to run speaker wire down one side and power down the other. I think that's the better way.

But thanks for the idea. I'm going to mock up a test and see if I can tell the difference.

Craig.
My wife says I can't do sarcasm. She says I just sound like an a$$hole.
Post 4 made on Sunday July 27, 2014 at 00:27
pilgram
Loyal Member
Joined:
Posts:
November 2004
5,684
I've never experienced noise at speaker level in this situation but I suppose it could happen,just not likely.

The code question depends on the inspector.

If he considers the molding to be a "pipe" then it will have to be separate run.

If that's the case,a trip around the wall with a 1/2" router bit through the drywall with a trim router and some 1/2" pvc on wall conduit should make him happy and also isolates the high from the low which is a good thing when it comes to liability.
Every day is a good day.......some are just better than others!

Proud to say that my property is protected by a high speed wireless device!
Post 5 made on Sunday July 27, 2014 at 01:05
Dave in Balto
Super Member
Joined:
Posts:
January 2008
2,771
No way is this up to code. And no it technically should not be done. And no low voltage contractor for the point of saying it should ever install a power outlet when he finds out that he needs one some where.


With that said, I doubt that something like this would be inspected. I've done it before once or twice because there was no other option, performance wasn't effected, and we made sure that we tied the wire tight to the corner so it didn't get shot.

Never thought about Ernie's idea to twist the wire, makes sense anyway. If I'm in the situation to do it again I'll use it .


Just don't put nails into the wire, use a 4-5" crown to be safe.
Hey, careful man, there's a beverage here!

The Dude
Post 6 made on Sunday July 27, 2014 at 01:15
Ernie Gilman
Yes, That Ernie!
Joined:
Posts:
December 2001
30,104
On July 26, 2014 at 23:30, Craig Aguiar-Winter said...
I won't be doing the electrical but I imagine the electrician will use armoured cable to avoid any miss fired nails puncturing it. If this is the case and I can't twist it is this install doomed?

No, not at all, and I'm sorry I didn't say that you probably won't have any problem AT ALL. The lower the impedance of a circuit is, the less likely there will be interference from adjacent wires. Power amps attempt to have zero ohms source impedance... and, so, well, that's low, right? !

The interference that you could have is magnetic in origin, and if the wires are surrounded by metal of low resistance, that lowers the magnetic effect. Armored cable will be even less of a problem than Romex.
A good answer is easier with a clear question giving the make and model of everything.
"The biggest problem in communication is the illusion that it has taken place." -- G. “Bernie” Shaw
Post 7 made on Sunday July 27, 2014 at 01:35
para19
Long Time Member
Joined:
Posts:
December 2012
124
You could cut out a 2-3 inch strip in the drywall that will be covered by the crown moulding. Then drill holes through the studs and run your wiring through the studs and the electrician can run his wire along the surface if he wants. I imagine that BX would cut down on any possible interference vs. NMD (Lomex). CEC Code states at least 2" separation between LV and HV.
There is always money in the banana stand...
Post 8 made on Sunday July 27, 2014 at 01:37
bcf1963
Super Member
Joined:
Posts:
September 2004
2,767
Ernie's suggestion about twisting the Romex sounds decent, until a little analysis of what you're really dealing with...

Here in North America, power is 120V 60Hz. You're certainly not going to change any impedance matching characteristics, and therefore the coupling characteristics, by putting a couple twists for every 5 feet. Even if you were to twist it 100 times every 5 feet, it's not going to make much if any difference at 60Hz. 60Hz is practically DC, and twisting will have very negligible effects on coupling due to electric or magnetic fields at these frequencies. It might affect the ability of the audio to get onto the AC, but I don't think we're worried about that!

The biggest factors are coupling, and proximity. Normally you handle this by using spacing, but this isn't a great option. So that leads to changing the coupling.

If you are worried about coupling, you could run shielded speaker cable. Another possibility might be balanced audio cables, with the amplification built into the speakers. (I don't if know if speakers with balanced inputs to an onboard amp is common, but would certainly work from an electrical perspective.) The other possibility is to shield the AC. This could be done by using BX (Now referred to as Type AC in the code).

I would think any of those would work, and the BX might be nice anyway, as it will prevent a nail from puncturing the AC when putting up the moulding.
Post 9 made on Sunday July 27, 2014 at 02:11
King of typos
Loyal Member
Joined:
Posts:
June 2002
5,275
I honestly don't see this job, for the electrician, as being illegal if he uses the proper raceway. This would be ideal for the electrician... [Link: homedepot.com] But don't quote me as being correct, quote me as it's an idea that could be true. lol

I can tell you this though, if the electrician uses something like that. By code you can not attach to his raceway. No strings, zip-ties or anything. So if you are going to run with the raceway, you must attach your wire to the wall by itself.

KOT
OP | Post 10 made on Sunday July 27, 2014 at 06:56
Craig Aguiar-Winter
Senior Member
Joined:
Posts:
September 2002
1,489
That's all very useful. Thanks guys.

Craig.
My wife says I can't do sarcasm. She says I just sound like an a$$hole.
Post 11 made on Sunday July 27, 2014 at 07:38
highfigh
Loyal Member
Joined:
Posts:
September 2004
8,311
Why not install small-diameter conduit or flexible conduit for the speaker cable? It would be protected from nails, it wouldn't be considered to be in the same conduit as high voltage and it could provide a bit of noise rejection. If it's not too small, it's not terribly difficult to feed the cable through it.
My mechanic told me, "I couldn't repair your brakes, so I made your horn louder."
OP | Post 12 made on Sunday July 27, 2014 at 09:14
Craig Aguiar-Winter
Senior Member
Joined:
Posts:
September 2002
1,489
I though about that but I will likely have to turn one corner and I don't think I could fit a conduit corner in behind the moulding. Worth checking into though.
My wife says I can't do sarcasm. She says I just sound like an a$$hole.
Post 13 made on Sunday July 27, 2014 at 13:11
Mario
Loyal Member
Joined:
Posts:
November 2006
5,681
On July 27, 2014 at 01:05, Dave in Balto said...
No way is this up to code. And no it technically should not be done. And no low voltage contractor for the point of saying it should ever install a power outlet when he finds out that he needs one some where.

Dave, are you saying that running line and low voltage wires next to each other is not up to code, the fact that running them so close to surface (just behind crown molding), or something else?

I get why we shouldn't run line and low voltage close to each other, but where in NEC does it say that we can't?
Post 14 made on Sunday July 27, 2014 at 13:30
kgossen
Super Member
Joined:
Posts:
March 2008
3,026
On July 27, 2014 at 01:05, Dave in Balto said...
No way is this up to code. And no it technically should not be done. And no low voltage contractor for the point of saying it should ever install a power outlet when he finds out that he needs one some where.

My low voltage license allows me to run my own power when needed.
"Quality isn't expensive, it's Priceless!"
Post 15 made on Sunday July 27, 2014 at 13:57
77W
Advanced Member
Joined:
Posts:
June 2012
971
On July 27, 2014 at 13:30, kgossen said...
My low voltage license allows me to run my own power when needed.

Really? How long has that been the case in BC, and what is the extent of "when needed"?

If this was the case in Ontario, "when needed" would have us wiring up our own lighting enclosures. Half the electricians we work with don't want to have to read specs and drawings and most of the others that do read them think it's a guideline open for interpretation.


Jump to


Protected Feature Before you can reply to a message...
You must first register for a Remote Central user account - it's fast and free! Or, if you already have an account, please login now.

Please read the following: Unsolicited commercial advertisements are absolutely not permitted on this forum. Other private buy & sell messages should be posted to our Marketplace. For information on how to advertise your service or product click here. Remote Central reserves the right to remove or modify any post that is deemed inappropriate.

Hosting Services by ipHouse