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Author Topic: Clips on the bus bars directly inside a panel?  (Read 3700 times)

Rusty Stevens

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Clips on the bus bars directly inside a panel?
« on: February 01, 2016, 10:37:37 AM »

Taking the way back machine to the late 80's, popping open a circuit panel at a venue (bar or hotel) and clamping leads to the bus bars for a distro was pretty much the norm.
I rescently saw a distro in use that was still being tied into house power this way. My older, possibly wiser, and much more parinoid self thought "that can't be safe".
In my search for adding a possible future distro to my system, I've gone as far as consulting with electrcians that I know on how to get power safely. The gerneral suggestion is that i purchase the 3 common breakers for the panels in use around here and add/remove a circuit to the panel when I set up and tear down. I'm more inclined to plug a distro into an existing outlet specified in a pre-check of the venue, but I'd rather not turn away work if I can.
Is there a legitimate way/reason to patch directly into a live power panel with a distro, without an electrician onsite?
Thanks
Rusty
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TJ (Tom) Cornish

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Re: Clips on the bus bars directly inside a panel?
« Reply #1 on: February 01, 2016, 10:53:31 AM »

Taking the way back machine to the late 80's, popping open a circuit panel at a venue (bar or hotel) and clamping leads to the bus bars for a distro was pretty much the norm.
I rescently saw a distro in use that was still being tied into house power this way. My older, possibly wiser, and much more parinoid self thought "that can't be safe".
In my search for adding a possible future distro to my system, I've gone as far as consulting with electrcians that I know on how to get power safely. The gerneral suggestion is that i purchase the 3 common breakers for the panels in use around here and add/remove a circuit to the panel when I set up and tear down. I'm more inclined to plug a distro into an existing outlet specified in a pre-check of the venue, but I'd rather not turn away work if I can.
Is there a legitimate way/reason to patch directly into a live power panel with a distro, without an electrician onsite?
Thanks
Rusty
Short version - no. 

Longer version - unless you are qualified and have permission to do the work, you can't break the cord and plug rule. If you need a tool to open or tighten something, you're over the line and in danger of significant liability.

For recurring venues, discuss getting the power you need installed so you can just plug in.  For one-offs, paying an electrician or renting a generator are your legal choices.

It might be worth trying to lower your rig's power requirements so you are less likely to need a distro.

When all else fails, sometimes the venue just can't handle the level of production and you either need to say no to the gig, or right size the gig to the venue.
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Tim McCulloch

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Re: Clips on the bus bars directly inside a panel?
« Reply #2 on: February 01, 2016, 12:19:58 PM »

Taking the way back machine to the late 80's, popping open a circuit panel at a venue (bar or hotel) and clamping leads to the bus bars for a distro was pretty much the norm.
I rescently saw a distro in use that was still being tied into house power this way. My older, possibly wiser, and much more parinoid self thought "that can't be safe".
In my search for adding a possible future distro to my system, I've gone as far as consulting with electrcians that I know on how to get power safely. The gerneral suggestion is that i purchase the 3 common breakers for the panels in use around here and add/remove a circuit to the panel when I set up and tear down. I'm more inclined to plug a distro into an existing outlet specified in a pre-check of the venue, but I'd rather not turn away work if I can.
Is there a legitimate way/reason to patch directly into a live power panel with a distro, without an electrician onsite?
Thanks
Rusty

Ugggg.  I still encounter bands from south of the border (and their USA transplants) that use jumper cable clamps.  I remember the use of TriCo welding clamps back in the 1980s as well.  There's a small avalanche of Code violations involved, starting with that you're leaving an open panel energized (especially bad if in a publicly accessible area) and the clamps are not Listed for this use.

Like TJ, my answer is "no."  Have I popped a breaker into an empty slot in a hot panel?  Uh.... I plead the 5th, but I haven't done it in a long time and won't do so in the future, either.  Even if I'm competent to do so I'm not licensed or insured to do so.  Add in the potential for an ugly arc flash incident (for which I do not have PSE) and it's a no-go.

I've been in your trenches, Rusty, and I know what you're running into.  What I did in the past concerned me back then and today it scares the hell out of me.  There are some very lucky old guys out there, but don't conflate luck and longevity with acceptable practice.
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Rusty Stevens

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Re: Clips on the bus bars directly inside a panel?
« Reply #3 on: February 01, 2016, 01:46:39 PM »

Thank you both for confirming my thoughts on this matter.

My requirements are actually laughably low, mostly from the use of efficient amplifiers, and a reasonable number of LED fixtures. I'm trying to future proof for that out door gig at a country bumpkin bar with a single 15A edison for the band and rig. I can make it work, but don't much like it. My screwdriver shall only touch what I own!

Most shows the amperage meters show that I'm averaging about 5A draw for lights and sound. I guess that's partially because my amplifiers are barely working most of the time. I'm sure I'll be bumping into power issues at some point, and I like to be prepared.

Thanks
Rusty
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TJ (Tom) Cornish

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Re: Clips on the bus bars directly inside a panel?
« Reply #4 on: February 01, 2016, 01:57:07 PM »

Thank you both for confirming my thoughts on this matter.

My requirements are actually laughably low, mostly from the use of efficient amplifiers, and a reasonable number of LED fixtures. I'm trying to future proof for that out door gig at a country bumpkin bar with a single 15A edison for the band and rig. I can make it work, but don't much like it. My screwdriver shall only touch what I own!

Most shows the amperage meters show that I'm averaging about 5A draw for lights and sound. I guess that's partially because my amplifiers are barely working most of the time. I'm sure I'll be bumping into power issues at some point, and I like to be prepared.

Thanks
Rusty
Rusty, I wrote about some of these issues as your situation is very common.  Take a look:

http://tjcornish.com/articles/understanding-power-consump.html
http://tjcornish.com/articles/power-distribution-part-1--.html

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John Daniluk (JD)

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Re: Clips on the bus bars directly inside a panel?
« Reply #5 on: February 01, 2016, 02:56:05 PM »

Several years age I was tying in 100a single phase into a Church ac panel for a band.  After disconnecting the incoming power I opened the box.  A buss bar was burned 3/4 in half.   i asked what happened, it seems another band  was installing clamps and shorted the buss bar.  I put my breaker in above where the bar was gone.  i informed the Church that they have a big problem and need to replace the ac box. 

A little side note on this:

We were going to play at another Church one Sunday.  I went to tie in my show and the door on the ac panel was so hot (temperature) I could not hold my hand on it very long.  I refused to tie in and we cut way back on the sound and did not do lights.  The band went back 2 weeks later and did not use me.  They used a licensed electrician to tie them in.  Yes the panel was hot.  They started sound check with full lighting, big bang, good by outside main transformer.  The power company was p......d.  The power company refused to restore power to the building until an electrical inspection was done, a day or two later. 

I glad I refused to tie in

JD

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TJ (Tom) Cornish

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Re: Clips on the bus bars directly inside a panel?
« Reply #6 on: February 01, 2016, 03:14:32 PM »

Several years age I was tying in 100a single phase into a Church ac panel for a band.  After disconnecting the incoming power I opened the box.  A buss bar was burned 3/4 in half.   i asked what happened, it seems another band  was installing clamps and shorted the buss bar.  I put my breaker in above where the bar was gone.  i informed the Church that they have a big problem and need to replace the ac box. 

A little side note on this:

We were going to play at another Church one Sunday.  I went to tie in my show and the door on the ac panel was so hot (temperature) I could not hold my hand on it very long.  I refused to tie in and we cut way back on the sound and did not do lights.  The band went back 2 weeks later and did not use me.  They used a licensed electrician to tie them in.  Yes the panel was hot.  They started sound check with full lighting, big bang, good by outside main transformer.  The power company was p......d.  The power company refused to restore power to the building until an electrical inspection was done, a day or two later. 

I glad I refused to tie in

JD
Arc flashes are a BIG DEAL. 

Here's the most sobering thing I've ever seen posted on PSW: http://forums.prosoundweb.com/index.php/topic,155930.msg1431986.html#msg1431986

Don't be that guy.
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Stephen Swaffer

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Re: Clips on the bus bars directly inside a panel?
« Reply #7 on: February 01, 2016, 03:33:18 PM »

Arc flashes are a big reason non-electricians (and honestly some electricians) should stay away from energized panels.  What you don't know can and will hurt or kill you.  And a clamp that slips from your grip is a nasty arc flash just waiting.

Most people do not realize how warm or hot properly functioning, if heavily loaded equipment and wire can be.  Consider that 60 deg C wire = 140 deg F and 75 deg wire=167 deg F.  And that is the temperature it will run when continuously loaded to the ampacity listed in the charts.  I had tech doing an infrared scan flag a dry transformer once-yes it was hot to the touch (as well as infrared obviously) but it was well within its design limits.  One reason a transformer should never be buried in a closet or have stuff pilled on the nice flat convenient top.
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Steve Swaffer

Rusty Stevens

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Re: Clips on the bus bars directly inside a panel?
« Reply #8 on: February 01, 2016, 04:40:24 PM »

I got nailed by a 28,000VAC Jacobs Ladder that we had on display for Electronics Tech in high school. Never really had the stomach for messing with power more than I had to after that.

I powered it down, moved it to a safer location because it was arcing at folks walking by, plugged it in, pulled my hands back, and powered it on... It arced to my knuckles and held me there till someone knocked me off the table I was kneeling on to put the display up on a high shelf.
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John Roberts {JR}

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Re: Clips on the bus bars directly inside a panel?
« Reply #9 on: February 01, 2016, 05:47:21 PM »

I just want to thank the OP for spelling bus correctly....(good job).  8)

JR
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Re: Clips on the bus bars directly inside a panel?
« Reply #9 on: February 01, 2016, 05:47:21 PM »


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