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Author Topic: Should I ground the Stage on Asphalt?  (Read 14650 times)

Mike Sokol

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Re: Should I ground the Stage on Asphalt?
« Reply #40 on: July 03, 2014, 04:31:27 pm »

Maybe we need a vise grip like thing with a lug on it to connect a cable? It could clamp pretty securely to flat and round objects.

I did exactly that about 40 years ago. I kept a pair of Vice-Grips with a wire lug screwed to the side in my band roadcase with a roll of #8 green stranded wire. After clamping it to a known ground (big metal water pipe in the basement) I would put a wrap of e-tape around the latching handle. I was pretty confident that it wasn't going to come loose. Hey, I've accidentally left a pair of Vice-Grips clamped under my trailer for a year and heaven knows how many miles. Found them a year later still clamped onto the frame.  ;D

I don't think Vice-Grips would pass inspection nowadays and I've never seen it mentioned in code for use a temporary ground, but I'll bring it up as a possible solution with my contact on the NEC 2017 committee when I present my bed-o-nails temporary ground solution. In the meantime, we can't recommend Vice-Grips as a safe or code compliant solution except in a post zombie apocalypse scenario.   :o
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Mike Sokol
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Frank DeWitt

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Mike Sokol

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Re: Should I ground the Stage on Asphalt?
« Reply #42 on: July 03, 2014, 05:00:01 pm »

http://www.scottgrossstore.com/servlet/the-5447/Tweco-Welding-Ground-Clamp/Detail


Frank - Good find. If this is UL approved for grounding a welder, there's a chance it could also be approved for temporary AC grounding. I'll run this by the grounding and bonding forum on Mike Holt's website. Perhaps they know or can quote code about this sort of application.
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Mark Cadwallader

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Re: Should I ground the Stage on Asphalt?
« Reply #43 on: July 03, 2014, 05:15:16 pm »

http://www.scottgrossstore.com/servlet/the-5447/Tweco-Welding-Ground-Clamp/Detail


Lighting folks use a similar clamp to attach lighting fixtures to round pipe. The "Altman" C-clamps are a standard item that lampies should be familiar with, and which they often have an extra one or two of with their gear.  I offer no judgement as to the suitability of those clamps for electrical purposes.  Mark C.
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Mike Sokol

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Re: Should I ground the Stage on Asphalt?
« Reply #44 on: July 03, 2014, 05:24:05 pm »

Lighting folks use a similar clamp to attach lighting fixtures to round pipe. The "Altman" C-clamps are a standard item that lampies should be familiar with, and which they often have an extra one or two of with their gear.  I offer no judgement as to the suitability of those clamps for electrical purposes.  Mark C.

Good info. I'll toss that into my inquiry to Mike Holt's forum.
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Stephen Swaffer

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Re: Should I ground the Stage on Asphalt?
« Reply #45 on: July 05, 2014, 08:13:30 am »

The "code speak" term is "listed for the purpose"-for that you'd have to check manufacturers data sheets, i am guessing-if you can find them. 

The other term used is "solidly connected".  I think common sense would lead to the conclusion that vice grips with a permanent welded lug, or a mechanical connection like a C clamp with a screw would be a solid connection, vs a spring type clamp like jumper cables-how many times have you had one slip off in the 2 minutes it takes to get a car started?

Practically, I am happy with something that gives a solid connection.  On the liability side, the UL listing would help the lawyers, since I often wonder about their common sense.  One works and keeps everybody else safe-the listing protects your finances IMO.

BTW-code still recognizes copper clad Al.  Also, FWI, ground rods are usually copper clad iron (steel).  They all conduct electricity a lot better than earth.
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frank kayser

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Re: Should I ground the Stage on Asphalt?
« Reply #46 on: July 07, 2014, 06:58:17 pm »


I wrote to the stage manufacturer requesting assembly instructions and whether their  engineers have an approved methodology to accomplish connecting their staging to EGC  and to earth ground. To my dismay (but not to my surprise)  I received the answer:
------------------------
Hello Mr. Kayser,

Attached are stage assembly instructions. We do not have an approved methodology for accomplishing grounding for the stages.

Please let me know if you have any questions.

Thank you.

Sincerely,
----------------------

Believing this would be the reply, I was looking at grounding lugs - I found two that look like possible candidates - UL Listed.  Of course, the uses of these are different from bonding an outdoor stage.  These are lay in lugs which would allow a single large-gauge wire to be a continuous bonding conductor - the first easily applied/removed from the stage sections and cable laid in.

Mike, think you could run these up the flagpole over at Mike Holt's forum?

http://unitedstructuralproducts.com/product/us-tray/components/bonding-and-grounding/ground-wire-clamp/
Datasheet indicates "cable tray"...  (I'd post a picture, but my past attempts have ended in failure...)
http://www.elecdirect.com/catalog/df208983-6f76-455f-b7b7-91bc983c6c39.aspx
Talks about use on roof solar panels - also have seen identical parts cable trays and direct burial.

Both come made from different materials...

Some products mention UL Pub 467, so I thought I'd take a peek.


http://www.techstreet.com/products/1854110
UL Pub 467 Grounding and Bonding Equipment - 50 pages - $631.00

Ouch!  I know someone has to pay for the work.  I'm wondering how many electricians have a copy or access to a copy. 

I really like the musicians I work with - just trying to be safe.

frank
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Mike Sokol

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Re: Should I ground the Stage on Asphalt?
« Reply #47 on: July 07, 2014, 07:07:27 pm »

I'm not sure what this means or if it's relevant to the topic, but it sure is funny. Let's see... don't pee from an ungrounded stage?

« Last Edit: July 07, 2014, 07:10:53 pm by Mike Sokol »
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Jonathan Johnson

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Re: Should I ground the Stage on Asphalt?
« Reply #48 on: July 07, 2014, 07:24:55 pm »

I'm not sure what this means or if it's relevant to the topic, but it sure is funny. Let's see... don't pee from an ungrounded stage?

If you're far enough away from the electrified surface you are urinating on, due to the surface tension of water, the stream will become broken droplets and you won't be shocked. That doesn't mean I'm going to test the theory.

Back in my younger days (most of you would probably say I'm still in my younger days) I worked as a laborer on a Christmas tree farm. One of the farmhands on the shearing crew needed to relieve himself and picked the electric fence to do so... my brother (the landowner and boss) and I both watched amusedly waiting for it -- why warn a young punk when you're about to see the best entertainment in years? -- but that lucky city-slicker didn't even experience the slightest discomfort.
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Mike Sokol

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Re: Should I ground the Stage on Asphalt?
« Reply #49 on: July 07, 2014, 08:29:27 pm »

but that lucky city-slicker didn't even experience the slightest discomfort.

One time I accidentally rode my bicycle through an electric fence when I was a kid. Nothing intermittent about that and it hurt like heck.
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Mike Sokol
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Re: Should I ground the Stage on Asphalt?
« Reply #49 on: July 07, 2014, 08:29:27 pm »


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