New Installation Wire Gauge

[brad14]

Hello, I'm new to the forum and have a few questions. I'm in the process of designing the AV system for a church that's being built. (Long story but the old church burnt down due to someone driving their car into the side of it.) We're building completely new from the ground up. The sanctuary will hold about 150 people. I bought some twisted pair shielded cable to run from the AV booth to the stage. The length of each run will be no more then 75 feet. I did some research before hand and it seemed that most line level balanced runs use 22 AWG twisted pair. I ordered some West Penn 291 wire and it arrived the other day. After looking at the size, I'm wondering if I should have gone with 18 AWG. We're also on a shoe-string budget so money was the main driver towards the 22 AWG, otherwise I would have went with 18 AWG. Should I stick with 22 AWG or switch to 18? Money is important but I also don't want to have to redo everything. I was looking at 1000' spools. Thanks.

[brad14]

Sorry. I forgot to mention that these audio runs are for the mixer inputs. They would connect the mics and a keyboard (on the stage) to the mixer (in the AV booth). I have heavier wire, 14 AWG, for the main speakers.

[Gracetech]

West Penn 291 is used by a few contractors that i have run into in the past. By no means is it the best thing out there but it will do everything you need it to do. I'm sure you were not expecting such a scrawny looking cable by the sounds of it. All contractor cables are around that size for balanced line. In short runs like yours you will see no difference in different gauges.

Just be sure to double check everything you solder.

BTW welcome to CMN!

crt

[waynehoskins]

First, welcome.

I don't see any reason why #22 wouldn't be adequate. #24 and even #26 are used for snakes these days. I generally prefer #22 because it's a bit more rugged. Not usually an issue in a permanent install (or even in most portable snakes).

Common install cables are West Penn 291 like you have, 452, and Belden 8451 and 9451. They're all in the same class, 22-24 AWG twisted pair with a foil shield and drain wire. Generally I prefer to pull snake cable even in an install, for a couple of reasons. If you're pulling to the same place (or a small number of places with several mic jacks), it's just as easy to pull snake as individual runs, plus you don't have to pre-cut each piece. Each pair is easy to identify on both ends, either from identification on the pair jacket if it's IJ, or the wire colors. Non-IJ snake is also smaller in cross-section than the same number of 9451 or similar, which can be a factor when pulling in conduit.

Let me recommend running conduit if you can. It will make the pull so much easier. Free-space pulls sometimes want to make you rip your hair out.

Also, free-space or conduit, you'll want to pull a pull string with the cables. You will thank yourself later, especially if it's in conduit.

[tedanderson]

Yeah, the West Penn 291 is the spec for most government installations that I do. I've also used it to wire up racks and it works pretty good. I even use it to make my RS232 cables to the projector.

As Wayne said, get a snake if you can but if you have more time on your hands than money, pulling individual runs out of that 1000' box is the way to go.

[Brad Weber]

You've gotten very good advice already, but it perhaps should be noted that I believe all of the cables mentioned are rated for running in walls but are not rated for plenum applications. If you are running cable exposed above ceilings, below floors, in chases, etc. then you would need to make sure those are not considered plenum spaces. If they are plenum spaces then you will have to use plenum rated cable, which is why there are plenum rated versions of most of the cables noted.

[brad14]

Thanks for all the suggestions. I guess I will stick with the wire I have. I did look into snakes but they were a bit more expensive so I will have to pull multiple runs to the same spot. I guess I have more time then money so it's not too big of a deal. I'm also running the wire down into the crawlspace below the building which is about 4.5-5' deep so I have plenty of room to work with. Running conduit would be nice but that would be another added expense. I was planning on using PEX pipe suspension clamps to support the cable in the crawlspace. We have a lot leftover from the plumber.

I also had a question about balanced/unbalanced connections. I can wire everything up for balanced but a lot of equipment - mics, guitars, etc are unbalanced. For those connections would I need to run the mics and guitars through a direct box before I send them to the mixer board? Thanks.

[Gracetech]

You really would benefit from running the cable in a pipe. You can use PVC, It's not free but it's pretty cheap. Hanging wire from pipe clips really doesn't work as well as you are thinking.

Yes a D.I. box is what you need to convert unbalanced loads to balanced.

crt

[jdcountryboy91]

Great info guys. I'm in a similar situation. Basically we are adding a few more amplifiers behind the stage for floor monitors and a few more floor boxes for stage inputs. Can ya'll point me towards a 12 channel snake (bare wire on both ends) for installation. I found the whirlwind W1513. Is that what I need?

Any other brands I should look into? I know whirlwind can be pricy but its good stuff.

[waynehoskins]

Originally Posted by jdcountryboy91

Great info guys. I'm in a similar situation. Basically we are adding a few more amplifiers behind the stage for floor monitors and a few more floor boxes for stage inputs. Can ya'll point me towards a 12 channel snake (bare wire on both ends) for installation. I found the whirlwind W1513. Is that what I need?

Any other brands I should look into? I know whirlwind can be pricy but its good stuff.

Belden-Alpha, Gepco, Rapco-Horizon-VTG, Proco all come to mind. On the budget side, there are also the overseas companies like EWI.

What I'd really be tempted to do in your case is look on Ebay for either a suitable segment of bulk cable or something used that you could cut up. I recently picked up a 120-foot spool of Gepco plenum 8pr to run to our guitar amp iso room for cheap on Ebay (in my case, plenum rating wasn't necessary, but the price was right). Same discussion of ratings -- plenum, in-wall, etc. -- and conduit (you really want to run conduit; you'll thank yourself later) applies.

[Ray A. Rayburn]

Originally Posted by brad14

I also had a question about balanced/unbalanced connections. I can wire everything up for balanced but a lot of equipment - mics, guitars, etc are unbalanced.

I hope you do not have unbalanced mics. If you do consider getting balanced mics to replace them. A $20 balanced mic will likely sound better than any unbalanced mic, and will cost far less than an acceptable direct box.

[cmchamp]

Welcome Ray!