ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: 1 ... 15 16 [17] 18 19 ... 22   Go Down

Author Topic: Dangerous AC situation in reception hall - PLEASE READ  (Read 154058 times)

Mike Sokol

  • Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3361
  • Lead instructor for the No~Shock~Zone
    • No~Shock~Zone Electrical Safety
Re: freak accident? help!
« Reply #160 on: September 04, 2013, 08:30:19 AM »

Another question on the subject would be what is the effect of a  Ground Fault Interrupt GFI on the resulting problems.  I feel the  GFI would trip and shut down and potentially save the snake or DI box.  This would not fix the problem however.  It just screams trouble.

Here's the really interesting thing. I'm pretty sure that a GFCI in the receptacle itself MAY NOT trip during a ground fault event if it was mis-wired as an RPBG. And it certainly won't disconnect the ground pin from the incoming "hot" line even if it DOES trip. I see this in my head and have drawn it out and traced it on paper, but have never mis-wired one like this intentionally. But I'm in the 90% sure confidence range on this statement.

Wouldn't that be a real kicker if it's indeed true? I think this may have been the mis-wiring problem which killed the 12-year old girl in Orlando last year from a water feature pump on a miniature golf course. The news report said the GFCI was mis-wired so it didn't stop the current from killing her. I never saw the police report or pictures of the mis-wired GFCI, but it sure sound suspicious to me. Now THAT would be an interesting experiment to design and run.

Wonder if PSW would sponsor such an experiment. Is the forum moderator listening?

Mike Sokol   
« Last Edit: September 04, 2013, 08:40:36 AM by Mike Sokol »
Logged
Mike Sokol
mike@noshockzone.org
www.NoShockZone.org

Bob Leonard

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 6807
  • Boston, MA USA
Re: freak accident? help!
« Reply #161 on: September 04, 2013, 08:41:29 AM »

Mike,
I've been following this thread and would like to first say thank you for the time and effort you've spent on the subject.

I'm in the middle of a remodel project at home and am installing 12 6" remotely dimmed recessed lights, 14 outlets, media center wiring, etc. Basically I've gutted and rebuilt the living room, moved some walls, removed all of the 65 year old cable, etc.. Yesterday my Jr. electrician black lab ran away with my Fluke tester which has now gone to lab toy heaven. I needed to pick up some stock, and while doing that saw the Klein NCVT-2 and bought one.

Why don't you like the -2 dual range tester?
Logged
BOSTON STRONG........
Proud Vietnam Veteran

I did a gig for Otis Elevator once. Like every job, it had it's ups and downs.

Mike Sokol

  • Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3361
  • Lead instructor for the No~Shock~Zone
    • No~Shock~Zone Electrical Safety
Re: freak accident? help!
« Reply #162 on: September 04, 2013, 08:51:38 AM »

Mike,
I've been following this thread and would like to first say thank you for the time and effort you've spent on the subject.

I'm in the middle of a remodel project at home and am installing 12 6" remotely dimmed recessed lights, 14 outlets, media center wiring, etc. Basically I've gutted and rebuilt the living room, moved some walls, removed all of the 65 year old cable, etc.. Yesterday my Jr. electrician black lab ran away with my Fluke tester which has now gone to lab toy heaven. I needed to pick up some stock, and while doing that saw the Klein NCVT-2 and bought one.

Why don't you like the -2 dual range tester?

I do like the Klein NCVT-2 and works just fine in my tests, but for the casual user it's way easy to get confused when setting the high-low/beep-quite modes. For a professional like yourself I think it's a good choice.

You do read directions, don't you? We all know that 99% of the time the directions are still unread in the shrink wrap years later. Keeps them nice and safe, I guess... For the average consumer, just getting them to remember to turn on the switch is asking too much. 

Mike Sokol
« Last Edit: September 04, 2013, 09:10:59 AM by Mike Sokol »
Logged
Mike Sokol
mike@noshockzone.org
www.NoShockZone.org

Mike Sokol

  • Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3361
  • Lead instructor for the No~Shock~Zone
    • No~Shock~Zone Electrical Safety
Re: freak accident? help!
« Reply #163 on: September 04, 2013, 09:08:36 AM »

Duh, double post....
« Last Edit: September 04, 2013, 09:11:45 AM by Mike Sokol »
Logged
Mike Sokol
mike@noshockzone.org
www.NoShockZone.org

Mike Sokol

  • Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3361
  • Lead instructor for the No~Shock~Zone
    • No~Shock~Zone Electrical Safety
Re: freak accident? help!
« Reply #164 on: September 04, 2013, 09:10:02 AM »

Yesterday my Jr. electrician black lab ran away with my Fluke tester which has now gone to lab toy heaven.

PLEASE post a picture of the Fluke chew-toy.

Mike
Logged
Mike Sokol
mike@noshockzone.org
www.NoShockZone.org

Geoff Doane

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 886
  • Halifax, NS
Re: freak accident? help!
« Reply #165 on: September 04, 2013, 09:37:28 AM »

Here's the really interesting thing. I'm pretty sure that a GFCI in the receptacle itself MAY NOT trip during a ground fault event if it was mis-wired as an RPBG. And it certainly won't disconnect the ground pin from the incoming "hot" line even if it DOES trip. I see this in my head and have drawn it out and traced it on paper, but have never mis-wired one like this intentionally. But I'm in the 90% sure confidence range on this statement.

Wouldn't that be a real kicker if it's indeed true? I think this may have been the mis-wiring problem which killed the 12-year old girl in Orlando last year from a water feature pump on a miniature golf course. The news report said the GFCI was mis-wired so it didn't stop the current from killing her. I never saw the police report or pictures of the mis-wired GFCI, but it sure sound suspicious to me. Now THAT would be an interesting experiment to design and run.


If the GFCI was wired as RPBG, then it is a shock hazard by definition.  The hot wire is connected to ground, and nothing inside the GFCI will disconnect the ground, no matter what happens.  It should still trip if a 2-wire device was plugged in and had a ground fault.  This would be a rare case of a 2-wire device being safer than a properly "grounded" one.

Apparently a common mistake with GFCIs is that the installer mixes up the LINE and LOAD sides, which even with a proper ground, makes them ineffective.  To make matters worse, I suspect the TEST button on the GFCI will still indicate that it is working properly, even if it's mis-wired. 

Older GFCIs simply compared the current on the hot and neutral, and tripped if the difference exceeded a certain threshold.  This doesn't protect against an open neutral, because the circuit needed to be powered for it to work.  Newer units add the requirement of voltage potential on the LINE side before they will make the connection to the outlet and LOAD terminals.

GTD
Logged

TJ (Tom) Cornish

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4284
  • St. Paul, MN
Re: freak accident? help!
« Reply #166 on: September 04, 2013, 09:37:52 AM »

PLEASE post a picture of the Fluke chew-toy.

Mike
The Flukes are CAT rated.  Maybe they need to work on a DOG rating.

Ba dum...
Logged

Bob Leonard

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 6807
  • Boston, MA USA
Re: freak accident? help!
« Reply #167 on: September 04, 2013, 12:17:45 PM »

I wish I could post a picture. we let her get to be a fatty (88lbs), and the vet had us put her on a diet. She's down in weight now, but always hungry. So I'm working on the wiring and I hear a beeping sound. This lab goes shithouse over chew toys that beep so at first I thought she had one of her toys until I hear my wife yell "God damn it Lucy, give that back.", the universal lab signal to play keep away.

Well the door was open so the dog ran out to the fenced yard, all the time going beep, beep, beep. I got down off of the ladder, went outside, and by the time I could get to her and chase her down it was gone to doggy toy heaven without a trace.
« Last Edit: September 04, 2013, 04:55:30 PM by Bob Leonard »
Logged
BOSTON STRONG........
Proud Vietnam Veteran

I did a gig for Otis Elevator once. Like every job, it had it's ups and downs.

Mike Sokol

  • Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3361
  • Lead instructor for the No~Shock~Zone
    • No~Shock~Zone Electrical Safety
Re: freak accident? help!
« Reply #168 on: September 04, 2013, 12:47:57 PM »

I got down off of the ladder, went outside, and by the time I could get to her and chase her down it was gone to doggy toy heaven without a trace.

My wife had Dobermans when she was growing up. One would eat ANYTHING, such as a hamburger right out the hot frying pan on the stove, or a beret from her school band uniform, and a Timex watch right off the dresser. The beret and watch made it through the doggie recycling process, but the beret was never the same, and the Timex didn't "keep on ticking" since the crystal broke on a tooth while the dog was chomping it down. They were planning to send the watch into the Timex "Keeps On Ticking" television ad campaign at the time, but it was not to be...

Perhaps someday you'll find your Fluke tester in a hole somewhere. If so, you should see if it still works and offer to send it to Fluke for a replacement. I'll bet they'll send you a new one in trade just for fun.

Mike Sokol
« Last Edit: September 04, 2013, 07:30:47 PM by Mike Sokol »
Logged
Mike Sokol
mike@noshockzone.org
www.NoShockZone.org

Mark McFarlane

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1865
  • Middle East
    • Arkose Records
Re: freak accident? help!
« Reply #169 on: September 04, 2013, 02:09:29 PM »

A few 'curious' observations from my year-old Fluke Volt Alert 2AC (90-1000V) (always on, but with a battery test button)

1) Anywhere within two inches of my Macbook Pro wallwart and it lights up
2) Anywhere within about 4 inches of my MacBook Pro laptop it lights up
3) Anywhere within an inch of my Apple Airport Express and it lights up
4) On a cheap outlet strip (9 outlets spread over 30 inches) (that is plugged into a GFCI outlet) it doesn't light up anywhere, including inserted into the hot legs, but the outlet strip powers devices.  The GFCI 'source' tests fine.  I haven't opened up the outlet strip (yet) to see how it is wired.

On a dozen other outlets around the house it seems to work correctly.
Logged
Mark McFarlane
ARKOSERECORDS
Turn down what's too loud.

ProSoundWeb Community

Re: freak accident? help!
« Reply #169 on: September 04, 2013, 02:09:29 PM »


Pages: 1 ... 15 16 [17] 18 19 ... 22   Go Up
 



Site Hosted By Ashdown Technologies, Inc.

Page created in 0.245 seconds with 22 queries.