Speaker Cables & AC Wires

[NetGeek]

I took great pains to separate my AC cords from the interconnects & speaker cables in my rack. I ran Belkin 5000 UE 12ga unshielded cable for speaker wire up through the walls and in my attic to reach my surrounds & rear surrounds. At two places the speaker wires cross a bundle of AC power lines in the attic; they cross the AC lines at a right angle and are about 2 feet away from the power lines.

Since I have not completed hooking my system yet up I have no idea if these AC lines will cause EMI interference in my speakers. What is the general rule on how far your speaker wires should be from AC power lines? Is it possible to shield the speaker wire where it crosses the AC lines by running it through a short length of metal pipe, or could I put a thin sheet-metal plate or even tin-foil over the AC wires where the speaker wires cross, would this effectively shield my speaker wires from interference?

 

[JohnA]

You should be fine...at two feet away I don't think you will have a problem! If speaker lines can be run in the next bay over from electrical (only 16") with no problem then 24" away should be more than enough

 

[NetGeek]

Thanks for the info John

I guess you are talking about cable chase used on one of your professional installations right? I never fully understood why speaker cable is not shielded, I have never seen shielded speaker wire.

 

[warpdrive]

speaker wire is not shielded because normally, it doesn't have to be. In 99% of the applications, it won't make a difference. You could buy 8 gauge fully EMI shielded cable and use it for your speaker cable, but your wallet will be a lot lighter.

 

[JohnA]

I guess you are talking about cable chase used on one of your professional installations right? I never fully understood why speaker cable is not shielded, I have never seen shielded speaker wire.

Nope...just talking about the regular stud bay in the wall.

 

[Dumar]

What is the general rule on how far your speaker wires should be from AC power lines?

The greater the separation the better, but the 16" rule is generally accepted as a good one to follow (as JohnA points out) and is obviously convenient due to standard wood-frame construction techniques. The key however, is not to run your cables parallel to AC lines. If there is no way to avoid a parallel run, maximize the separation and keep the run as short as possible.

Where speaker cables (and other low voltage wiring) cross AC lines at 90 degrees, EMI will not occur. In other words, at any angle less than 90, some amount of EMI will occur with the value approaching zero at 90 (lets not do the math ). It is possible to use (properly grounded) shields to prevent interference, as you suggest, but in your case is absolutely not necessary.

It sounds like you've done a great job. Get it hooked up, turn it on, and enjoy.

I couldn't find spec's on the cable you used, but if it was wisted pair that will also help minimize the effects EMI. With twisted pair, the tighter the lay the better.

 

[warpdrive]

I think you will be ok.

 

[Mrhappysuncle]

Same Wire, Different Scenario

I'm wiring my unfinished basement right now and I had no choice but to almost touch 110 and 220 wires in my runs.

What type of conduit or shield would you guys recommend?

 

[mtrycrafts]

I'm wiring my unfinished basement right now and I had no choice but to almost touch 110 and 220 wires in my runs.

What type of conduit or shield would you guys recommend?

Avoid that setup if at all possible. If not, use twisted wire, better rejection.

 

[Mrhappysuncle]

Thanks

I'll try to re-route as much as possible.

 

[manofsteel2397]

im doing a speaker run across my basement and all power lines for the whole house are in my way they are all inclosed in a wood box that runs from the conjuction box to the breaker box with a 1" plywood covering the wires but i need to cross this to run my speaker wires i am running 12gage in wall speaker wire will this pose a problem

 

[highfigh]

I'm wiring my unfinished basement right now and I had no choice but to almost touch 110 and 220 wires in my runs.

What type of conduit or shield would you guys recommend?

This is EMI, not RF and the best way to keep hum out is with distance. There's really no good shielding for speaker level cable runs but, OTOH, it's usually not a problem. There are literally hundreds of thousands of buildings where the speaker and power lines are closer than 16" and they don't have problems. If they must cross, they should be at right angles.

 

[caper26]

I would worry more about the sub cable than speaker wires...get one that is shielded...if you are really paranoid, twist your speaker wires near the AC lines, but I think you will be ok