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Author Topic: Wiring A Stage For AC Power  (Read 6803 times)

Mark Cadwallader

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Re: Wiring A Stage For AC Power
« Reply #10 on: February 04, 2015, 08:07:38 pm »

+1

I know none of the inspectors I deal with would allow SO or SJ cable for this use.  Since this is a "place of assembly", the NEC only permits metallic raceway/cable wiring methods.  The main issue being smoke generation if a fire does start.

If the issue is money, ask your contractor.  As a contractor, I would rather (especially with non-profits) supervise a couple of volunteers than have someone come in after the install and hack the install-imo, better to do that than wind up trying to prove who did what.  (That may not be possible everywhere-inspectors in my area are generally easy to work with and more interested that the job is supervised and done right than in who has a license and who does not-there are provisions here for "unclassified" persons so we can usually fudge a bit.

Just to make sure I understand, you are saying that SO or SJ would not be allowed to be placed in conduit as part of a permanent installation. SO or SJ cable would be required for "portable" uses such as in a stage stringer, but a special type of strain relief attachments (a gland-type attachment) are necessary.  Do I have that right?  Mark C.
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Tim McCulloch

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Re: Wiring A Stage For AC Power
« Reply #11 on: February 04, 2015, 08:17:48 pm »

Just to make sure I understand, you are saying that SO or SJ would not be allowed to be placed in conduit as part of a permanent installation. SO or SJ cable would be required for "portable" uses such as in a stage stringer, but a special type of strain relief attachments (a gland-type attachment) are necessary.  Do I have that right?  Mark C.

Correct.  Clamps for non-metalic sheathed cable (Romex) cannot be used on portable cords like SO.  Code requires that materials Listed for the use be employed, and Romex clamps are not Listed for use with portable cordage wiring products.

In general, running jacketed AC cable in conduit is prohibited.

NEC Chapters 2, 3, & 4 lay this out.
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Kevin Graf

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Re: Wiring A Stage For AC Power
« Reply #12 on: February 04, 2015, 09:19:17 pm »

I have standard 20A-125V outlets.  GFCI won't fit inside the stage boxes.
There are small GFCI dual receptacles designed to fit in old small outlet boxes.

WE899
http://www.leviton.com/OA_HTML/ProductDetail.jsp?partnumber=WT899-GY&section=42318&minisite=10251
« Last Edit: February 04, 2015, 09:23:12 pm by Kevin Graf »
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Bill Harvey

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Re: Wiring A Stage For AC Power
« Reply #13 on: February 04, 2015, 09:29:54 pm »

Or you could use GFCI breakers in the feed panel and then just use standard receps in the boxes.
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Don Lomonaco CFCRC

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Re: Wiring A Stage For AC Power
« Reply #14 on: February 04, 2015, 09:53:30 pm »

I'll post a pic of the stage.  I know we're not planning on moving it but it could be moved.  It's just standard stage pieces on mounts with a wooden border made to surround it.  The whole thing can certainly come down and it's not part of the overall room structure.  It kinda sounds like it would be easier if it were classified as portable.

I am just trying to build a glorified 'stringer'.

I like the idea of using GFCI on the wall outlets.  That's an easy alternative.
« Last Edit: February 04, 2015, 09:56:06 pm by Don Lomonaco CFCRC »
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Mark Cadwallader

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Re: Wiring A Stage For AC Power
« Reply #15 on: February 04, 2015, 11:13:26 pm »

Don, besides the Lex products that Tim gave a link for, O.A. Windsor has ultra-tough rubber boxes suitable for stage stringers. They also will custom build stringers to meet your needs, and offer boxes that can be linked together using PowerCon connectors, so you can re-configure the layout as needed.  I have plans to get some of their PowerCon/NEMA 5-20 boxes after I get some other things I need sooner. I've heard of O.A.Windsor products still going strong after 20-30 years of rock 'n 'roll duty, so they will be a good (albeit pricey) investment for me.

Best wishes for finding a good, safe solution to your stage power needs. Mark C.
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Stephen Swaffer

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Re: Wiring A Stage For AC Power
« Reply #16 on: February 04, 2015, 11:45:33 pm »

Specifically, NEC 400.7 tells you were SO is allowed and 400.8 were it is not.  The list of uses is very specific-and  one of the more clear areas of code-really hard to win an argument about it voice of experience.  Just being portable doesn't always work.

FWIW, my price on MC cable is about 60% of the cost of SO.  Correct fittings for MC cost less than SO correct fittings for SO. If the boxes have 1/2" KOs, I could wire this as quick or quicker with MC than with SO.  For me to do it code compliant would be less costly than using SO.

I understand that a lot of it is familiarity, etc-but I am amazed how many times I come into fix something done by a non-electrician, and they have skimped and taken short cuts-but then they use higher priced materials where unnecessary-and often end up with an inferior job.

The only potential savings I see would be if you wire it with smaller wire-say #16 SO-which (while a code violation) would likely work for its intended use, but what happens when the cleaning crew comes in and plugs the industrial carpet cleaner into the nice convenient receptacles on the stage?  Now you could have a problem!
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Jay Barracato

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Re: Wiring A Stage For AC Power
« Reply #17 on: February 05, 2015, 08:48:16 am »

I think there is some confusion over the word "portable" in this thread. The codes being referred to are not calling the stage portable but the outlets.

It sounded like you were asking about what are commonly called stage drops where the wire would sit on top of the stage running to a box which could be moved around. That is one set of codes.

If you are talking about a boxed permanently mounted with the wire running under the stage that is a different set of codes.

I am not sure which you are looking for because both the original post and the responses have a hodgepodge of both.

Sent from my DROID RAZR HD using Tapatalk

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Jay Barracato

Jay Barracato

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Re: Wiring A Stage For AC Power
« Reply #18 on: February 05, 2015, 08:52:30 am »

I'll post a pic of the stage.  I know we're not planning on moving it but it could be moved.  It's just standard stage pieces on mounts with a wooden border made to surround it.  The whole thing can certainly come down and it's not part of the overall room structure.  It kinda sounds like it would be easier if it were classified as portable.

I am just trying to build a glorified 'stringer'.

I like the idea of using GFCI on the wall outlets.  That's an easy alternative.

Given this response, it doesn't matter whether the stage is movable or not. The key point is that the outlet is movable and the wire is exposed on stage. Lex has their products but I have a lot of O.A. Windsor. I use their rubberized boxes with have appropriate strain relief built in with SO cable.

Sent from my DROID RAZR HD using Tapatalk

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Jay Barracato

Stephen Swaffer

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Re: Wiring A Stage For AC Power
« Reply #19 on: February 05, 2015, 10:05:18 am »

I agree with Jay-I originally pictured this as stage boxes mounted in the stage.

If boxes are in the stage building codes apply and the  NEC prohibits concealed SO and as well it would have to be considered an appliance to use SO.

An exposed stringer should use SO with the correct fittings.

As for GFCI location, if the receptacle on the wall is GFCI, the downside is that a trip takes down everybody.  If the Levition GFCIs will work (they really nice!), the a GFCI trip would only shut part of the stage down.  Less interruption-and fewer places to look for a problem.
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Steve Swaffer

ProSoundWeb Community

Re: Wiring A Stage For AC Power
« Reply #19 on: February 05, 2015, 10:05:18 am »


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