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[Glenn Whitehead]

I am working with a local theater as a sound tech.  They have a snake installed between the stage and FOH.  It is installed in an EMT conduit.  The conduit has electrical conduit on both sides of it for about 75 feet.  Should we try to move the snake run away from the AC lines or is this ok?

Also, the speaker wires are just sitting on top of the drop ceiling.  I want ot put them into a conduit of their own.  Is it OK to put multiple speaker runs in the same conduit?

Thanks,

Glenn Whitehead

[Brad Weber]

Glenn Whitehead wrote on Fri, 15 August 2008 09:36

I am working with a local theater as a sound tech.  They have a snake installed between the stage and FOH.  It is installed in an EMT conduit.  The conduit has electrical conduit on both sides of it for about 75 feet.  Should we try to move the snake run away from the AC lines or is this ok?

Are you having any noise problems on the snake lines?  How close is the AC run to the audio conduit?  Ideally there should be some separation but you might very well be better with it as is in EMT conduit than rerouted outside conduit.

Quote:

Also, the speaker wires are just sitting on top of the drop ceiling.  I want ot put them into a conduit of their own.  Is it OK to put multiple speaker runs in the same conduit?

Provided the cables fit and meet code requirements for conduit fill, it shouldn't be a problem.

[Glenn Whitehead]

There is a lot of noise in the system.  I have not proven where it is coming from yet.  THe AC lines are about 1 inch on both sides.  There are about 5 AC runs, the snake run, then 2 more ac runs.  If I re run the snake I would keep it in a conduit.

Thanks,

Glenn Whitehead

[Charlie Zureki]

Glenn Whitehead wrote on Fri, 15 August 2008 09:30

There is a lot of noise in the system.  I have not proven where it is coming from yet.  THe AC lines are about 1 inch on both sides.  There are about 5 AC runs, the snake run, then 2 more ac runs.  If I re run the snake I would keep it in a conduit. Thanks, Glenn Whitehead

 
 Glenn,

  I would check everything in the System from Mics through, to Speakers before you start moving Conduit. Moving Conduit is, as you can imagine a big job.

  What kind of noise is it?
  Is it a hiss or hum?

  Hisses- usually from improper gain structure.
  Hums- usually grounding problems.

  Pls give us more info.
 Cheers,
 Hammer

[Don Boone]

"Provided the cables fit and meet code requirements for conduit fill, it shouldn't be a problem."

Conduit fill doesn't apply to low voltage cables. 800.110

Don

[Glenn Whitehead]

I would say it more of a hum.  In some cases a crackle.  It gets worse when it rains.  I will check it out some more.  AC power comes from different panels within the building.

The last 30' of the shake is not in the conduit.  If I prove that the noise is from the snake I would start by fixing the last 30'.

Thanks,

Glenn Whitehead

[Charlie Zureki]

Glenn Whitehead wrote on Fri, 15 August 2008 11:26

I would say it more of a hum.  In some cases a crackle.  It gets worse when it rains.  I will check it out some more.  AC power comes from different panels within the building. The last 30' of the shake is not in the conduit.  If I prove that the noise is from the snake I would start by fixing the last 30'. Thanks, Glenn Whitehead

 Glenn,

  Two seperate Problems...

  Sounds like a bad Electrical system ground. (when it rains)

  You're probably also getting a ground loop when using "different panels" within the building.

 Good Luck,

 Hammer

[Brad Weber]

To clarify, I was suggesting following the code requirements for cable fill and not that it would be a code violation to not follow them, in this case that is two different things but I can see it being confused.  There are good reasons for the recommended fills and I do not know any training or certification program or manufacturer that doesn't recommend it.

[Charlie Zureki]

Brad Weber wrote on Fri, 15 August 2008 12:17

To clarify, I was suggesting following the code requirements for cable fill and not that it would be a code violation to not follow them, in this case that is two different things but I can see it being confused.  There are good reasons for the recommended fills and I do not know any training or certification program or manufacturer that doesn't recommend it.

  Brad,

    +1

   I would always want to leave plenty or room in conduit anyway, regardless of Codes. It's easier to add more wire/cable. Leave a pull string too!

Cheers,
Hammer

[Duane Massey]

If it doesn't need to be in conduit, I'd rather not put a bunch of cables in conduit. If the cabling is plenum cable, it can be a challenge, as the insulation can really tear easily, and if it is a loose PVC/vinyl it can be a real pain, especially for a long pull with several bends.

I would not object to cleaning up a bunch of wires laying across the ceiling, but running speaker cables in a conduit doesn't really gain you very much, especially comparing the cost in an existing install.

Maybe it's just me, but I've found that pvc/vinyl cable needs a lot more space in a pipe than THHN. And pulling a pull string thru a pipe with several 22-2shielded cables is pretty much a waste of string, unless it's a really short or straight run.

YMMV, of course....