[dmtremblay]

I'm running power to my front projector with rubber insulated 12ga 3-conductor wire similar to this . I'm ceiling mounting the projector and would like to run both the signal cables and power cable through the extension tube on the mount. Is there a way to shield the power cable so that I don't get unwanted interference with the signal cables? I was thinking of running the power inside the tube (aluminum) and wrapping the signal cables around the outside to try and keep them as nonparallel as possible. Any ideas?


Thanks,

David

 

[hometheaterguy]

 http://www.partsexpress.com/pe/showd...D=119692&DID=7 Would shield well at that voltage. Use a hot knife to cut the sleeving.

 

[Swampfox]

You can't shield 60Hz with any practical thickness of a conductor.

 

[hometheaterguy]

So that braided shield wouldn't work? Is there anything (conduit) or anything else that might be able to sheild 60Hz EMI?

 

[dmtremblay]

So even a thick aluminum pipe wouldn't shield? I guess I either have to keep the power cord away from the signal cables or make sure it crosses the cables at a right angle. Does this sound right?

 

[Toxarch]

Don't you have to have a copper shield to protect against EMI? A short run of power and signal cables may not intruduce any problems you would notice.

 

[Swampfox]

Quote:

Originally posted by dmtremblay So even a thick aluminum pipe wouldn't shield? I guess I either have to keep the power cord away from the signal cables or make sure it crosses the cables at a right angle. Does this sound right?

Correct.

 

[Matt_Doug]

If you're willing to spend the cash get an isolation transformer with balanced output for your projector as 60 volts hot & neutral each with respect to ground will cancel any emi radiating from the ac cord.

 

[Swampfox]

Quote:

Originally posted by dmtremblay I'm ceiling mounting the projector and would like to run both the signal cables and power cable through the extension tube on the mount. Is there a way to shield the power cable so that I don't get unwanted interference with the signal cables? I was thinking of running the power inside the tube (aluminum) and wrapping the signal cables around the outside to try and keep them as nonparallel as possible. Any ideas? Thanks, David

If you are only talking about a foot, or so, I would not worry about it. Don't wrap your cables, keep them as short as possible. Keep things tidy. Keep the power cord short, and as far away from the signal wires as much as possible.

 

[philba]

I do exactly that with my PJ - power, component and coax all run through a 6 inch pipe. No interference at all.

 

[NightHawk]

I agree with Swampfox and Toxarch. Reasonable quality coax will provide adequate shielding for the video signals. No wrapping or special crossing angles are required. Supplemental shielding would be mostly infeffective since any coupling would be inductive.

 

[hometheaterguy]

From NightHawk: "No wrapping or special crossing angles are required".

It is standard practice when prewiring a home to have low volt wiring of any kind (coaxial, CAT5, structured cable and speaker wire) to cross romex (electrical) at right angles and be placed 18" away.
www.swhowto.com
www.lsdinc.com
www.cedia.net

 

[NightHawk]

Yes, I am aware that people do it but in my opinion it makes no difference except in rare cases.

 

[NightHawk]

I would just like to clairify my previous post by saying that in theroy and in practice, running two unshielded conductors parallel unquestionably increases inductive coupling. The raeson in makes no difference in a home theater setup is two-fold. The first is, properly connected shielded coax can reduce the inductive (and capacitive) coupling to the point of insignificance, even in parallel cables. Secondly, the power radiated by home power cords is insufficient to cause visable or audible interference in the video or audio interconnects because of the relatively low impedance of these circuits (75 Ohms for video and 8 Ohms for speaker level audio). These two factors in combination allow casually placing power cords and interconnects together without consequence.

 

[hometheaterguy]

I think the minority is 110V in the States, but it is still good to TRY and get any soft wire away from high volt. 220V on the other hand can cause real static and hum.