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#68991 - 08/23/06 05:46 PM got shocked &question
scott2828 Offline
New Member

Registered: 08/20/06
Posts: 6
Loc: east wenatchee
I got locked up for 3 sec. by the pos side of a 9000v 30ma ac transformer (?rectifier) and grounded by a 120v ac ground metal wall of a commercial building (safeway).
I got a lot of problems my doc is looking into but my question is will the amps be increased above the 30ma because i was grounded to the 120v ac plain? and how do I figure out the amps tha went through my arm/torso to help my doctor out.

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#68992 - 08/23/06 06:10 PM Re: got shocked &question
HotLine1 Offline

Member

Registered: 04/03/02
Posts: 6804
Loc: Brick, NJ USA
Scott2828:
Welcome to ECN, first

As to your question, the "AC" ground should not have any potential, if the installation is NEC compliant.

As to the neon transformer that 'bit' you, IMHO should not exceed the rated 30Ma. One of the other guys here (Scott35) may have better info.

That all said, your profile says you are a 'sign apprentice'......why did your foreman or boss allow you to get your body into a 'live' neon enclosure???

Neon signage deserves a LOT of respect; hence the required enclosures, conduit, etc on the high voltage GTO.

BTW: Good luck & a speedy recovery

John
_________________________
John

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#68993 - 08/23/06 06:31 PM Re: got shocked &question
Larry Fine Offline
Member

Registered: 02/18/05
Posts: 684
Loc: Richmond, VA
Most neon transformers have a grounded center-tapped secondary, so the shock voltage should have been 4.5 Kv. In theory, that alone would halve the current to a max of 15 ma.

Unless you are caught between points of opposing voltage (such as two transformers), there's no way you could conduct more current than the source can supply; simple Ohm's Law.

The resistance of your body also reduces the current. That you are alive and kicking indicates that the current you were subject to was probably below 5 ma, but it's a guess.
_________________________
Larry Fine
Fine Electric Co.
fineelectricco.com

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#68994 - 08/23/06 06:41 PM Re: got shocked &question
scott2828 Offline
New Member

Registered: 08/20/06
Posts: 6
Loc: east wenatchee
I was working with another apprentace of 1 1/2 years, we(unlawfully) had no journyman/admin. or any other supervisor on the job nor have we for the two weeks I have been working for the company(just got hired). the boss had been pushing us to get the job done due to his due date, i stepped into the center of the sign, dropped my strippers, bent over to pick them up and my butt was pushed onto the neon electroded on the glass housing as my hand was holding the angle iron on the opisite wall. The trainee that was with me desided that he needed to hurry and started to take the switch off the sign and accedently turnrd it on, followed by a very long scream, (doc thinks i blacked out for a breaf time) and finially my rear came off the electrode. Thankfully I had a set of dickes in my rear pocket with a thick wallet. it also destroyed my watch that was on my wrist. I could feel the pulsing of the current, that was weared! I just thought there has to be a reason for the extent of the injury.
OH OH, after the shock, my partner went to the base of the sign and tryed to unhook the 120v feed for the sign, there was a arc bettween the nutral and ground as he unhooked the wires, why would it do that? i thought nutrals only carred 2v or so?

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#68995 - 08/23/06 06:45 PM Re: got shocked &question
scott2828 Offline
New Member

Registered: 08/20/06
Posts: 6
Loc: east wenatchee
the transformers in the sign,,, if this helps there were 3 9000v and two 12000v, and they were all old and showed signs of heat discoloration, i did notice that they had a ground strap in the middel, one of them did have a black tar like stuff at the corner of the housing.

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#68996 - 08/23/06 06:50 PM Re: got shocked &question
scott2828 Offline
New Member

Registered: 08/20/06
Posts: 6
Loc: east wenatchee
thanks guys for your help, doc said i have nerve damage, and is worried about my spinal coum, weakness, dizzyness and felling lightheaded is anoying but the twitching in my hand and arm is driving me crazy! surpizingly I only had two small exit wounds in my hand and a small red mark on my but, I think thats because it didnt have to arc to get me.
thanks agian and any other info wound be great.

the one hand typing man!

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#68997 - 08/23/06 07:03 PM Re: got shocked &question
Roger Offline
Member

Registered: 05/18/02
Posts: 1779
Loc: N.C.
Scott, this is a very good what not to do thread. I hope you will have a complete recovery and only a bad memory of the event will be long lasting.

I am moving the thread to the Occupational Safety Discussion forum for further discussion, go to the link below.
http://electrical-contractor.net/ubb/Forum16/HTML/000303.html

Thanks

Roger

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