Speaker wire next to conduit with 220v?

Discussion in 'Home Theater Projects' started by chuck*, Dec 30, 2005.

  1. chuck*

    chuck* Auditioning

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    I’m a newbie to the forum. I’ve done some reading but I haven’t found this particular problem talked about.


    I recently bought a two-story house and I’m planning to install in-ceiling speakers. The in-ceiling speakers will be the rear channel on a 5.1 system. The room is located on the first floor, so attic space is out. I’ve figured out that the best option is behind crown molding. I would prefer to do it all via the ceiling but the ceiling joists run parallel to the wall that the TV is sitting on.

    I can either go left, right, or both with the wire. If I go right, the run is about 35 feet but it has to run next to a 220V wire that is inside ¾” conduit. If I go left, the run is about 70 feet and no conduit.

    If I run the wire next to the conduit will I get the 60Hz hum?
     
  2. Dick Knisely

    Dick Knisely Second Unit

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    If the 220V line is in metal conduit then no you shouldn't pick up anything from it -- the conduit is a shield. However, if you want to be really sure, then use shielded wire for the speakers.
     
  3. chuck*

    chuck* Auditioning

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    Yes it is in metal conduit.
     
  4. Phil A

    Phil A Producer

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    You can also buy 3M copper shielding tape for regular speaker wire if you have wire already and don't plan on buying add'l shielded speaker wire.
     
  5. Dick Knisely

    Dick Knisely Second Unit

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    Well I've learned to avoid the "never" and "always" words but if the power line is in a metal conduit then I wouldn't be concerned about it. But if you want to be really sure then ground the conduit (if not already grounded) and buy (or make per Phil's suggestion) shielded cables.
     
  6. Grant B

    Grant B Producer

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    When I was doing my house I went to our HW electrical design folks in our company (Aerospace... but friends help friends) and we found a paragraph in a Handbook that basically said:

    1) Keep data cables 2 inches from power where ever possible
    2) When crossing power; cross at 90 degree for phase cancelation whenever possible

    That should help
    Grant
     
  7. David_Rivshin

    David_Rivshin Second Unit

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    Keep in mind that unlike line level audio and data cables of all sorts, speaker connections are relatively high voltage. Of course they're not as high as the 120V going through the power wires, but they're still much less susceptible to interference. That's why you rarely see shielded speaker cables, but any decent interconnect is made out of well shielded coax.

    That said, I'd probably be paranoid and keep them as far from the power wires as conveniently possible.


    Must be either shielded data and/or power cables, some relatively low frequency data cables. I assume this handbook was for common airplane type wiring? 2 inches just seems way to close to me for your average home power lines and something like 100BaseT Ethernet over UTP. 2 feet would be where I'd start if they're going to be parallel for a long distance. But then again, I might just be paranoid [​IMG]

    -- Dave
     

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