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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Installed Sound/Contracting => Topic started by: Josh Coble on August 29, 2011, 09:50:11 am

Title: Permanently Installed stage snake HELP!
Post by: Josh Coble on August 29, 2011, 09:50:11 am
Installing a stage snake for a live gig is one thing..unroll it, connect xlrs, go! However, I have been chosen to permanently install a stage snake at a newly built HOW. I would like to have floor pockets for quick disconnecting. How would this work? I have a scenario that would work, however I feel that they may not be the most practical. Please advise!

Snake fantail at mixer...150' Rapco 24-channel xlr stage snake with 4 sends hidden in raceway to the stage. Female xlr snake box mounted and hid underneath stage. From there, 10'-25' xlr cables to the stage pockets....

Is there a better way to accomplish this? Doing it the way I described just seems unstable and not so much "permanent"...thanks for your help in advance!
Title: Re: Permanently Installed stage snake HELP!
Post by: Brad Weber on August 29, 2011, 12:13:02 pm
For permanent installs it is common to use bulk cable or at least cables not terminated (blunt cut) at the stage end and to make your own solder, crimp or compression connections to whatever connectors are involved on the associated plates, inserts and panels.

One aspect people often overlook with manufactured snakes is the actual installation aspect.  How will you pull a snake that has 28 connectors on one end and a box on the other?  That probably won't be run in conduit so will the cable run through walls or above ceilings or maybe even through a plenum space and if so, is the cable used in the snake appropriately rated?

The idea of running one larger 'snake' to the stage and then splitting out from there can often be a good concept, but you may need to consider how you will access those connections and whether you may be introducing additional points for problems or failures to occur.

Also, if you actually need 24 mic lines and 4 returns and are going to use a stage box to split things out then it might be a very good idea to run a larger snake, that way you will have some redundancy and potential expansion capability and often with a minimal additional cost.
Title: Re: Permanently Installed stage snake HELP!
Post by: Josh Coble on August 29, 2011, 01:30:13 pm
For permanent installs it is common to use bulk cable or at least cables not terminated (blunt cut) at the stage end and to make your own solder, crimp or compression connections to whatever connectors are involved on the associated plates, inserts and panels.

One aspect people often overlook with manufactured snakes is the actual installation aspect.  How will you pull a snake that has 28 connectors on one end and a box on the other?  That probably won't be run in conduit so will the cable run through walls or above ceilings or maybe even through a plenum space and if so, is the cable used in the snake appropriately rated?

The idea of running one larger 'snake' to the stage and then splitting out from there can often be a good concept, but you may need to consider how you will access those connections and whether you may be introducing additional points for problems or failures to occur.

Also, if you actually need 24 mic lines and 4 returns and are going to use a stage box to split things out then it might be a very good idea to run a larger snake, that way you will have some redundancy and potential expansion capability and often with a minimal additional cost.

Nice talking to you again, Brad! Thanks for the advice! My plans are for a "trough" to be built to house the snake xlr cable and the mains speaker cable. This will be recessed under the floor with a hidden hinge to open it. However, if this isn't feasible as construction allows, if I need to take it in the rafters, what is your suggestion? Cut the snake at the box and pull the xlr wires I need to each individual stage pocket? I know on the fan tail end the cables are usually labeled on the outer jacket 1-24, aux, etc. If I cut the large single outer jacket at the box to expose the xlrs, will they be labeled as well? OR do I need to put signal on each individual channel to determine which wire is what so that I may solder them to the appropriate connector on stage? The stage will be operating well under 24 xlrs, so its a safe buffer if we have any fouled channels. Thanks!
Title: Re: Permanently Installed stage snake HELP!
Post by: Jonathan Kok on August 29, 2011, 02:13:29 pm
Nice talking to you again, Brad! Thanks for the advice! My plans are for a "trough" to be built to house the snake xlr cable and the mains speaker cable. This will be recessed under the floor with a hidden hinge to open it. However, if this isn't feasible as construction allows, if I need to take it in the rafters, what is your suggestion? Cut the snake at the box and pull the xlr wires I need to each individual stage pocket? I know on the fan tail end the cables are usually labeled on the outer jacket 1-24, aux, etc. If I cut the large single outer jacket at the box to expose the xlrs, will they be labeled as well? OR do I need to put signal on each individual channel to determine which wire is what so that I may solder them to the appropriate connector on stage? The stage will be operating well under 24 xlrs, so its a safe buffer if we have any fouled channels. Thanks!
When it comes to cutting the snake, it will depend on the type of snake.  if it is an IJIS (Individually Jacketed, Individually Shielded) snake, the individual lines will be labelled by channel.  If it is not, then it won't, as each pair is simply wrapped in foil.  I believe the HOT wire is colour-coded, however; you'll simply have to undo the fanout ends to check colours.  Rapco's 'Club' series are not IJIS.  Can't speak to the others.  I know they have IJIS...but I simply order it in bulk, un-terminated.
If you intend to do as Brad suggested (which I would also suggest), then you will need IJIS cable.  The idea is to order a snake long enough to reach the FURTHEST floorbox, then unwrap the pairs to a common point, running the wires out individually to the boxes.  If you are going to a box, then you won't.  If the snake is not IJIS, make sure you cut the BOX end, as cutting the fan end will mean will have to shrink-wrap the pairs in the fanout.
Title: Re: Permanently Installed stage snake HELP!
Post by: Josh Coble on August 29, 2011, 02:24:42 pm
When it comes to cutting the snake, it will depend on the type of snake.  if it is an IJIS (Individually Jacketed, Individually Shielded) snake, the individual lines will be labelled by channel.  If it is not, then it won't, as each pair is simply wrapped in foil.  I believe the HOT wire is colour-coded, however; you'll simply have to undo the fanout ends to check colours.  Rapco's 'Club' series are not IJIS.  Can't speak to the others.  I know they have IJIS...but I simply order it in bulk, un-terminated.
If you intend to do as Brad suggested (which I would also suggest), then you will need IJIS cable.  The idea is to order a snake long enough to reach the FURTHEST floorbox, then unwrap the pairs to a common point, running the wires out individually to the boxes.  If you are going to a box, then you won't.  If the snake is not IJIS, make sure you cut the BOX end, as cutting the fan end will mean will have to shrink-wrap the pairs in the fanout.

Great Jonathan! Thanks for the heads up on the IJIS cabling. I'll look out for that. What you described as getting the cabling from the console to the stage is exaclty how I envisioned it. However, when I get to the stage and meet at a common point to disperse the unterminated xlr cable to their prospective boxes, how can I alleviate spaghetti under the stage? Thanks for your reply!
Title: Re: Permanently Installed stage snake HELP!
Post by: duane massey on August 29, 2011, 05:55:26 pm
I'll nearly always run individual cables if I'm going to multiple locations. You can get pre-labeled heat shrink from Rapco, Whirlwind, etc, and run either PVC or plenum shielded 2-conductor. I will nearly always use 22-gauge cable, although I see more and more 24g on other job sites. Of course, I'm an old guy who doesn't mind all the soldering involved, and I am no fan of the punch-blocks that are popular with installers with an IT background. As long as you get the proper cable from "A" to "B", and you meet code, it's all good.
Title: Re: Permanently Installed stage snake HELP!
Post by: Brad Weber on August 29, 2011, 10:23:12 pm
I have approached this several ways:
Which approach I use depends on factors such as the number of total connections, the number of connections in each floor box, whether any connections are paralleled to multiple plates, etc.
Title: Re: Permanently Installed stage snake HELP!
Post by: Jonathan Kok on August 29, 2011, 10:58:40 pm
I have approached this several ways:
  • Run multiple point-to-point individual cables.
  • Run a smaller multipair for each floor box or wall plate.
  • Run a large multipair to an accessible junction box at the stage and then smaller multipairs or individual runs from there to each floor box or wall plate.  Inside the junction box I tend to use screw terminal termination blocks as that supports testing and reconfiguration, although punchdowns or proper splices are also an option.
Which approach I use depends on factors such as the number of total connections, the number of connections in each floor box, whether any connections are paralleled to multiple plates, etc.
I've been debating the merits of pre-building racks to the point that even the mic line I/O runs to terminal blocks (DIN-rail).  Thoughts?  Ever used a ferrule on a mic line with a spring-type terminal block?
Title: Re: Permanently Installed stage snake HELP!
Post by: Jonathan Kok on August 29, 2011, 11:03:02 pm
Great Jonathan! Thanks for the heads up on the IJIS cabling. I'll look out for that. What you described as getting the cabling from the console to the stage is exaclty how I envisioned it. However, when I get to the stage and meet at a common point to disperse the unterminated xlr cable to their prospective boxes, how can I alleviate spaghetti under the stage? Thanks for your reply!
Ideally, you'd have everything contained within conduit.  If that's not feasible, then you do whatever you need to keep the wire off the ground and away from electrical.  Eye-ties (mountable zip ties), cable clamps, hooks, whatever.
Title: Re: Permanently Installed stage snake HELP!
Post by: Brad Weber on August 30, 2011, 07:38:30 am
One possible factor that I don't think has been addressed is the area under the stage and by that I mean aspects such as the stage construction, how much clearance there is, how accessible the area under the stage is and whether code and the AHJ may consider the area under it an accessible storage space.  If you can incorporate a trough as you originally planned that may not matter as much but if the boxes are to be set in the stage and the cabling to run under it then these can be relevant considerations.

For example, if it were an existing stage that is the flooring on sleepers that are on a concrete slab then the depth and orientation of the sleepers may dictate what is practical to do without tearing up the stage.
Title: Re: Permanently Installed stage snake HELP!
Post by: Josh Coble on August 30, 2011, 08:31:52 am
One possible factor that I don't think has been addressed is the area under the stage and by that I mean aspects such as the stage construction, how much clearance there is, how accessible the area under the stage is and whether code and the AHJ may consider the area under it an accessible storage space.  If you can incorporate a trough as you originally planned that may not matter as much but if the boxes are to be set in the stage and the cabling to run under it then these can be relevant considerations.

For example, if it were an existing stage that is the flooring on sleepers that are on a concrete slab then the depth and orientation of the sleepers may dictate what is practical to do without tearing up the stage.

Thanks you guys for all of your knowledge and help in this issue. Those are all certainly factors that I will look at and take into consideration. Is this the proper forum to list part numbers or vendors that may have these terminal blocks that I can disperse my cabling to the floor pockets once I get to the stage? If so, could you fellas shoot me some? That would be greatly appreciated. I am in IT and I punch down RJ45 into terminal blocks and keystone jacks all day long, so this would be easier.My hand isnt the steadiest soldering anymore.

What are your thoughts on cold heat soldering? Ive personally never used one, however, guys I've spoke with in the live sound business say they're good, but not for sensitive electronics...LEDS, precision board soldering, etc...anyone? Thanks guys!!
Title: Re: Permanently Installed stage snake HELP!
Post by: Thomas Lamb on August 30, 2011, 06:46:20 pm
Thanks you guys for all of your knowledge and help in this issue. Those are all certainly factors that I will look at and take into consideration. Is this the proper forum to list part numbers or vendors that may have these terminal blocks that I can disperse my cabling to the floor pockets once I get to the stage? If so, could you fellas shoot me some? That would be greatly appreciated. I am in IT and I punch down RJ45 into terminal blocks and keystone jacks all day long, so this would be easier.My hand isnt the steadiest soldering anymore.

What are your thoughts on cold heat soldering? Ive personally never used one, however, guys I've spoke with in the live sound business say they're good, but not for sensitive electronics...LEDS, precision board soldering, etc...anyone? Thanks guys!!

I typically measure the longest distance from the booth to the back wall of the stage to the furthest pocket and add some footage ( you NEVER want to be short) I order an IJIS snake fan to blunt in the length that I need. I will run it from the booth to the stage then I strip the outer sheath off and separate out the wires. It takes a little time but then I group them and route them to each individual box. The only connection I make is at the stage box.

Title: Re: Permanently Installed stage snake HELP!
Post by: Brad Weber on August 30, 2011, 07:03:28 pm
I order an IJIS snake fan to blunt in the length that I need. I will run it from the booth to the stage then I strip the outer sheath off and separate out the wires. It takes a little time but then I group them and route them to each individual box. The only connection I make is at the stage box.
I don't really know the answer but I am curious as to the code implications of that approach.  If you are running cable without conduit under a stage then that space would seem to either be considered  'accessible', in which case you may have to deal with exiting, sprinklers, lighting, etc., or 'inaccessible' and thus possibly require CL2 or better rated cabling.  And if air is returned under the stage through that space then plenum rated cable may be required.  But what happens when you peel the jacket off a cable for any distance?  Does it have any rating that would allow it to be used in an inaccessible area?  Does anybody know?
Title: Re: Permanently Installed stage snake HELP!
Post by: Thomas Lamb on August 30, 2011, 07:19:01 pm
I don't really know the answer but I am curious as to the code implications of that approach.  If you are running cable without conduit under a stage then that space would seem to either be considered  'accessible', in which case you may have to deal with exiting, sprinklers, lighting, etc., or 'inaccessible' and thus possibly require CL2 or better rated cabling.  And if air is returned under the stage through that space then plenum rated cable may be required.  But what happens when you peel the jacket off a cable for any distance?  Does it have any rating that would allow it to be used in an inaccessible area?  Does anybody know?

Most times I will run it to a junction box that has a main run of conduit typically installed by the electrical contractor. from there boxes on the stage conduit as well.

However, you bring up a valid point what exactly is the rating when you peel the jacket back is it acceptable at any point to run it without conduit in some situations?

It makes for a neat job when it is done!!