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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 => LAB Lounge => Topic started by: Michael Williams on July 28, 2011, 04:28:21 pm

Title: What bad power sources and/or "distros" have you seen?
Post by: Michael Williams on July 28, 2011, 04:28:21 pm
I was wondering the other day what folks have seen over the years as an excuse for a "distro", or power source. 

While wandering around eBay today this caught my attention.  Notice the "Ground Lift" switch.  Say what!?!?!?  And, do you see any breakers protecting those 15A and 20A Edisons?  Me either.   :P

Needless to say, this one makes it onto my "Are You Kidding Me?" list of things I hope I never come across.

Anything you guys (or gals) care to share so we can all have a laugh?  Got any pics?

...crossing my fingers no one get killed...
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Doug Fowler on July 28, 2011, 04:30:34 pm
Full name required, please fix in your profile.

TIA
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Paul John Volzone on July 28, 2011, 06:37:44 pm
The only thing scaring me on that is the Ground/Lift switch. I dont see a problem with no breaker on that. It has the 30A hubbel connection coming in whose circuit would be protected by a breaker back at the main distro. This just looks like your power supply for an amp rack. See these all the time.
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Mike Pyle on July 28, 2011, 09:19:58 pm
The only thing scaring me on that is the Ground/Lift switch. I dont see a problem with no breaker on that. It has the 30A hubbel connection coming in whose circuit would be protected by a breaker back at the main distro. This just looks like your power supply for an amp rack. See these all the time.

Assuming they have a 30a breaker on the 30a feeder, that isn't going to stop the 15a & 20a circuits from catching on fire if they are overloaded.
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Tim McCulloch on July 28, 2011, 11:13:27 pm
The only thing scaring me on that is the Ground/Lift switch. I dont see a problem with no breaker on that. It has the 30A hubbel connection coming in whose circuit would be protected by a breaker back at the main distro. This just looks like your power supply for an amp rack. See these all the time.

Paul, I'm not going to be a nice guy. 

DONT GIVE ELECTRICAL ADVICE, YOU ARE WRONG.

I strongly suggest that you go to your local library and read the National Electrical Code (NFPA-70), 2005 or newer edition.  Specifically you need to read and understand Article 200, 210 I and 210 II, 240 and 250; read through 300 to 312, most of it does not apply to our materials or methods but there are things that do; 400 through 408; 520 and 525; and 640.

You have your homework.

Tim Mc

ps. Mike Pyle explains what can happen.  The Code exists to minimize the opportunity for such things.  Electricity is an awesome but fearsome energy.  It can electrocute you or start the fires of hell.  Neither will get you a "good neighbor" recommendation.
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Marlow Wilson on July 28, 2011, 11:44:45 pm
Paul, I'm not going to be a nice guy. 

DONT GIVE ELECTRICAL ADVICE, YOU ARE WRONG.

I strongly suggest that you go to your local library and read the National Electrical Code (NFPA-70), 2005 or newer edition.  Specifically you need to read and understand Article 200, 210 I and 210 II, 240 and 250; read through 300 to 312, most of it does not apply to our materials or methods but there are things that do; 400 through 408; 520 and 525; and 640.

You have your homework.

Tim Mc

ps. Mike Pyle explains what can happen.  The Code exists to minimize the opportunity for such things.  Electricity is an awesome but fearsome energy.  It can electrocute you or start the fires of hell.  Neither will get you a "good neighbor" recommendation.

Not that this is something to joke about, but I love that they used orange outlets (Ie isolated ground outlets).

"but these are hospital grade outlets, what could possibly go wrong".....
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Paul John Volzone on July 29, 2011, 02:43:40 am

First off, I APOLOGIZE, and stand corrected. Thank you Tim; feel free to do so anytime.  Ive just seen many similar items but on short glance i didnt take time to soak in the defects visually, and run the numbers thru my head.(shall avoid putting my foot in my mouth in future  :-\) Appreciate the references to the NEC, and will make it some summer homework in the upcoming days.
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Jeff Bankston on July 29, 2011, 02:54:46 am
!!!
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Jeff Bankston on July 29, 2011, 03:12:04 am
!!!
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Jeff Bankston on July 29, 2011, 03:22:00 am
!!!
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Jeff Bankston on July 29, 2011, 03:22:56 am
The only thing scaring me on that is the Ground/Lift switch. I dont see a problem with no breaker on that. It has the 30A hubbel connection coming in whose circuit would be protected by a breaker back at the main distro. This just looks like your power supply for an amp rack. See these all the time.

Paul, I'm not going to be a nice guy. 

DONT GIVE ELECTRICAL ADVICE, YOU ARE WRONG.

I strongly suggest that you go to your local library and read the National Electrical Code (NFPA-70), 2005 or newer edition.  Specifically you need to read and understand Article 200, 210 I and 210 II, 240 and 250; read through 300 to 312, most of it does not apply to our materials or methods but there are things that do; 400 through 408; 520 and 525; and 640.

You have your homework.

Tim Mc

ps. Mike Pyle explains what can happen.  The Code exists to minimize the opportunity for such things.  Electricity is an awesome but fearsome energy.  It can electrocute you or start the fires of hell.  Neither will get you a "good neighbor" recommendation.
+1
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Jeff Bankston on July 29, 2011, 03:27:40 am
!!!
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Marlow Wilson on July 29, 2011, 08:38:20 am


Not that this is something to joke about, but I love that they used orange outlets (Ie isolated ground outlets).

"but these are hospital grade outlets, what could possibly go wrong".....
i have ordered a many a I.G. outlets for jobs where we installed them in computer server rooms of buildings. if you use an I.G. you must run 2 grounds. a green for the normal ground. a green/yellow stripe for the I.G. and it must be run all the way back to the transformer and terminted to the XO. have you seen the XO ?

I'm familiar with the other applications.  My suspicion is that they were chosen for this distro because they are somehow more 'professional' looking.  PDU's in IT that require an I.G. must include a separate enclosure ground that is absent from the pictured distro as far as I can see.

*I'm not an electrician*
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: TJ (Tom) Cornish on July 30, 2011, 12:51:06 am
as one who worked a day job as a commercial journeyman/foreman electrician for a number of years i say you need to first get a copy of the NEC and secondly study books on electrical wiring. "IF" that "outlet setup" in the foto is plugged into a 15 or 20 amp outlet fed by the breaker panel it will trip at 20.01 amps provided its a 20 amp breaker per NEC in commercial buildings.
Or 16 amps, or 60 amps or more, or anywhere in between, depending on the tolerance of that particular breaker, and the length of time the load is on.

This Siemens breaker chart shows that this particular type of breaker won't trip at 2X the rated load for more than 150 seconds:
http://www.sea.siemens.com/us/SiteCollectionDocuments/WSSResources/Internet/Products/110607/110607_18/VL-TCC-EG_806991_525_TM.pdf

Other breaker curves for other products are similar - 20 amps is a nice round rating, but is unlikely exactly the point at which a circuit trips.


15 amp breakers are illegal in commercial buildings. however "IF" those recepticals in the foto are "HARD WIRED" to the panel feeder lugs that is "ILLEGAL"
Pretty much anything hard wired, clamped, taped, etc. to the panel feeder lugs is illegal, other than the panel that is supposed to be there.

and a fire/electro-cution hazard since the wire is not protected. when using a jenny i use spider boxes which have a 50 amp main breaker 5 20 amp recepticles and 1 30 amp 2 pole and each has its own breaker. the foto below is the main switch gear i and 2 helpers installed to power a 9 story building in van nuys cali on van nuys blvd near vanowen st about 6 years ago. there is a lot to know about electrical wiring and TOO many opinions especially from musicians. i'm a drummer and have seen some stuff. my qsc power amps have ground lift straps on the back of them. in a 120 volt circut there are 2 wires. a hot leg and a neutral. the neutral is the return and is grounded in the system at the XO on the transformer in a commercial building. the GREEN wire is an extra ground in case the neutral takes a dump for some way out reason. not everything thats electric has the GREEN extra ground wire. some equipment has a HOT and NEUTRAL(return or ground). you ca get a ground loop caused from having too many grounds and it can cause an amp hum or electric shock.
I'm struggling to know what you mean by some of this - what ground lift straps on your amps are you referring to?  Is this something you fabricated?
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: TJ (Tom) Cornish on July 30, 2011, 01:10:09 am
Quote from: Mike Pyle
Assuming they have a 30a breaker on the 30a feeder, that isn't going to stop the 15a & 20a circuits from catching on fire if they are overloaded.
quoting Mike Pyles reply #3 above ^
YES IT WILL ! if that is plugged into or wired directly to a 20 amp breaker
I think you're contradicting what Mike said - since it appears from the photo that this is an L14-30, Mike is assuming this will be plugged into a 30A circuit, which, among other things, creates the problem with the 20A receptacles.


(illegal to install 15 amp breakers in a commercial building per NEC) and 20.01 amps are drawn the breaker SHALL TRIP !
Once again, this sounds nice, but isn't reality.  Breakers trip at a variety of different amperages, depending on the length of time at a particular over-current value.



a circut breaker is designed to protect the wire from overload. a circut breaker is not designed to trip due to a hot leg being grounded BUT they can and "sometimes" do.
The breaker sure better trip if there's a hot to ground short!!  It may not happen instantaneously - see above - but if a breaker fails to break the circuit on a low impedance connection to either ground or neutral, that's a severe failure - potentially lawsuit severe - and not a common one for low current branch circuits.



i have tried tracing wires in buildings buy grounding the HOT leg i want to find the breaker for to the J box only to have it make noise and not trip the breaker.
I'm not sure that's an IBEW approved way of finding a circuit!!


 i am NOT refering to a GFI breaker. #12 THHN2 copper wire in a conduit shall be protected by a 20 amp breaker. i do not recomend hard wiring a cord like in the foto above to a breaker. plugging both those cords into a duplex receptical will trip if the load reaches 20.01 amps. Dan Luckow electric rebuilds and sells circut breakers and if you want to know more about breaker trippage i suggest you contact him. his company is in Chatsworth Ca.
I'm not sure why you're stuck on this being plugged into a 20A circuit - it seems to me that this particular "distro" is a cheap and dangerous way to ensure the user would never blow a breaker in their amp rack, and I suspect it spent much of its dangerous life plugged into 30A outlets. 
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Jeff Bankston on July 30, 2011, 01:37:06 am
!!!
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: BobJohnson on July 30, 2011, 02:02:46 am
This picture I took in Baja in May at a Mother's Day festival with kids all over the place. This was in the back of one of two amp racks. Both looked like the picture though.
Talk about lucky nobody got killed!
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Jeff Bankston on July 30, 2011, 02:09:47 am
!!!
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Chris Carpenter on July 30, 2011, 02:12:12 am
let me explain some thing to you Tom Cornish > i worked as a commercial electrician for 10 YEARS
...rant...
 call TERRY Purden and ask him about the job i did. Terry is the owner.
I honestly can't tell if you are trolling, or actually serious.
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Jeff Bankston on July 30, 2011, 02:14:37 am
!!!
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Chris Carpenter on July 30, 2011, 02:39:14 am
I honestly can't tell if you are trolling, or actually serious.
if you like you can call my cell at 775-686-0575 and we will talk ! i'm waiting !
Now that's just entertaining.
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Todd Black on July 30, 2011, 02:45:13 am
a few things:

the ground lift strap on the back of an amp disconnects the external signal ground (pin 1 of the XLR) from the chassis of the amp. It does not disconnect the EGC (equipment grounding conductor). You basically never, ever, ever want to disconnect the EGC -besides potentially hurting someone you risk equipment damage. For example if I have an amp with no EGC connected to a mixer that is properly grounded and the amp develops a ground fault (short ie: hot wire touches the chassis) the only path for that current to flow is through the shield of the XLR into the mixer and out the mixers line cord.

NEC does not prohibit 15 amp branch circuits in commercial occupancies. There may however be local ammendments in some jurisdictions which do require a minimum branch circuit ampacity of 20 amps.

Isolated ground receptacles dont really have any place in portable power distribution. Some people use them because they look cool and thats fine as long as the strap and ground pigtail are bonded.

Most common circuit breakers of the thermalmagnetic variety found in 99.9% of all branch circuit applications will not trip at a fraction of an amp over their rating. Infact, the trip threshold varies with temperature and is of an inverse time delay nature. A 20 amp breaker can hold a load of 21 or 22 amps for a very long time.

One should never intentionally create a ground fault in an attempt to locate a breaker. Besides the potential for injury there is the risk of equipment damage. Depending on available fault current and the impedance of the circuit between the branch breaker and the fault there may not be enough current flowing to instantly trip the breaker. During this time more than enough current is flowing to cause equipment damage (especially if your wire welds itself to the box) This has been covered time and time again in the electrical trade and its a big no-no.

I could go on and on, but I know most of the professionals here are able to weed out the utter nonsense present in this thread.

Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Jeff Bankston on July 30, 2011, 02:51:47 am
!!!
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Todd Black on July 30, 2011, 02:54:45 am
oops, forgot to address one statement made earlier in the thread:

the equipment grounding conductor (EGC) 'green' is NOT there to provide a backup if the neutral were broken (nor would it provide this function unless the neutral and ground were improperly bonded somewhere along the line) the sole purpose of the EGC is to provide a path for fault current so the overcurrent protection device (breaker or fuse) opens. Scenario: Hot wire touches metal chassis, current flows from the hot wire through the chasis out the ground wire back to the source, enough current flows to instantly trip the breaker and the situation is rendered safe. Without the EGC in place, and metal parts properly bonded, the metal would remain energized and anyone touching it would receive a shock.
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: TJ (Tom) Cornish on July 30, 2011, 08:33:02 am
let me explain some thing to you Tom Cornish > i worked as a commercial electrician for 10 YEARS
...rant...
 call TERRY Purden and ask him about the job i did. Terry is the owner.
I honestly can't tell if you are trolling, or actually serious.
Thanks for preserving that!  It made my morning.
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Chris Carpenter on July 30, 2011, 01:43:04 pm
I honestly can't tell if you are trolling, or actually serious.
Thanks for preserving that!  It made my morning.
You should have seen the video; I'm so glad I saved it to my hard drive.
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Jeff Bankston on July 30, 2011, 02:05:37 pm
!!!
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Jeff Bankston on July 30, 2011, 02:08:56 pm
!!!
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Jeff Bankston on July 30, 2011, 02:22:19 pm
just want to express my thanks to all the professional sound engineers here at PSW for their help and advice. thank you , Jeff
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: TJ (Tom) Cornish on July 30, 2011, 02:42:44 pm
just want to express my thanks to all the other professional sound engineers here at PSW. however tom cornish and chris carpenter decided they know more the me , a man that worked as a commercial electrical with a journeyman certification card for 10 years. i posted a w2 form and gave the name of my boss and his fone number for them to call to verify what i claim. they just put me down more. these kind of know it all guys have an ego so big it is impossible for them to learn. after they continued to give me sheeeet i decided to remove my replys. i recorded a cpoyrighted video just for cornish and carpenter to link to. if that video appears anywhere on the internet copyright infringement charges will be filed against carpenter and cornish. this forum is here to HELP those who have questions. you should stay off here if you want to make fun of people and cut people down. thank you , Jeff
Preserving this for posterity too.

Jeff - no one doubts you were/are an electrician - unfortunately a lot of people doubt the accuracy of what you've posted.

This forum - as you have said - is all about learning. Fortunately for everyone there is a lot of peer review to make sure the curriculum is accurate.
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Chris Davis on July 30, 2011, 03:52:29 pm
You should have seen the video; I'm so glad I saved it to my hard drive.

That was quite the video... :o
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Chris Carpenter on July 31, 2011, 02:03:44 am
that video is copyrighted
I don't want to share the video, I want to watch it every time I'm feeling down. I seriously thought you were kidding until this morning when you removed the posts, now I feel kinda sad, must have been a bad night.

and if you post it i will have the url traced and sue you.
The word you are looking for is IP address. You trace IP addresses, not URLs. Also, that wouldn't get you very far either. Your best course of action would be to file a complaint with the host. Even then, legal action likely wouldn't ensue.

why dont you show your face or are you just a sissy typing big while hiding behind a keyboard ?
My face is available at any time at uberchris.com. Given, those are a few years old at this point, but it doesn't really matter.

"Chris Carpenter" decided they know more the me
Show me the post where I said anything about electricity? I only critiqued your internetsmanship.
Title: Re: What bad power sources and/or "distros" have you seen?
Post by: Jeff Bankston on July 31, 2011, 03:27:39 am
that video is copyrighted
I don't want to share the video, I want to watch it every time I'm feeling down. I seriously thought you were kidding until this morning when you removed the posts, now I feel kinda sad, must have been a bad night.

and if you post it i will have the url traced and sue you.
The word you are looking for is IP address. You trace IP addresses, not URLs. Also, that wouldn't get you very far either. Your best course of action would be to file a complaint with the host. Even then, legal action likely wouldn't ensue.

why dont you show your face or are you just a sissy typing big while hiding behind a keyboard ?
My face is available at any time at uberchris.com. Given, those are a few years old at this point, but it doesn't really matter.

"Chris Carpenter" decided they know more the me
Show me the post where I said anything about electricity? I only critiqued your internetsmanship.
no it wasnt a bad night. i was a forman for 6 of the 10 years. i have had guys come on my crew that had their journeyman certification card that by law is required IF you are hired as a journeyman electrician. i fired a lot of those guys within the first day and remember firing one within the first hour. we started thinking that guys would go take a journeyman class that preps you for the test and virtually gives you the answers. iirc (its ben a while) you have to have a minimum of 8000 hours steadly working as a commercial/industrial electricain in order to take the test. we(other journeyman & company bosses) figure guys will lie on the application about experience , go take the class and somehow pass the easy multiple choice test and get the certification. california was going to require a printout from the social security administration to very the employers that we worked for but during my time that never happened. so what we had is guys that only had maybe 1 year experience as an apprentice electrician claiming they could do it all & that can be deadly. i had several guys hired by the boss and sent to my job that didnt know what a fishtape, mc cable, tie wire, emt, etc was and they had there journey card that the boss ran through the cali website that verified they were. my point is if you havent taken a course or studied books on electrical wiring your not qualified to give advise on the subject. it normally takes a couple of years to learn the about "some" of the basic stuff. theres much more to wiring than just thinking that "all" 12 gauge wire for example will handle the same amount of current>amps. thhn2 is what you will find in newer buildings but theres a lot of 40+ year old buildings with wire that isnt rated for the same amount of current(12 ga for example) because of the type of insulation. wire in a condiut is derated to handle less amps then the same wire in free air. i'm just trying to let you know why i get intense when it comes to electricity. i have had a few coworkers get killed because they did (that was the final report) a job they said they could do but apparently didnt really know how to do it. i dont claim to know everything about electricity and i never wired houses and i would have to got study the nec if i wanted to wire a house. all my work was commercial and some industrial. i hope you understand that i was trying to get peoples attention when it comes to doing your own wiring and having the knowledge when it comes to powering your pa with the house panel(s). in my opinion its would be better to buy a power distibution unit(s) that have ben tested and have the UL rating then to build your own. one plus about buying a setup is IF it were to cause a problem while being used as intended the liability would fall on the manufacturer should injury or damage to property occur. this is my last reply on this thread. 
Title: Enough
Post by: Mac Kerr on July 31, 2011, 01:29:05 pm
Bu bye.