Original poster: "John Richardson" <jprich-at-up-dot-net>
Hi Dave,
I am glad that you brought this subject up, and was hoping that you could
offer some insight into my problem. I am getting to the point in the
basement where the streamers are getting long enough to start hitting things
that they shouldn't be, ie house wiring. I have moved everything as far
away from gas lines, wires, etc, but after having added another quick coiled
up piece of dryer duct, things changed dramatically. While tuning, I went
from no output to tremendous output, with streamers longer than expected,
and therefore hitting the Romex in the ceiling. I didn't expect this. If I
run chicken wire on the ceiling, and ground it out, will this be enough to
keep things safe? I think it would. Also, what are the thoughts on a
dedicated line filtered 120v line for all coiling activities? I DON'T want
fires, and I am at a level now that concerns me. Up until recently, I've
been a firefighter and hazmat tech for various volunteer departments, and
having seen the aftermath of carelessness, I want to avoid it.
Thanks,
John Richardson
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Tuesday, March 09, 2004 10:34 PM
Subject: Safety--NFPA70E and Flashover Clearance Info
> Original poster: David Sharpe <sccr4us-at-erols-dot-com>
>
> List
>
> At work we've started (US) NFPA70E training for qualified electrical
> personnel (i.e Electricians, Ttechnicians, Electrical Engineers).
> NFPA70E
> covers "Flash/Arc, Electrical Explosion" events, and proper personal
> protective equipment (PPE), approach distances, proper tools,
> equipment
> procedures, etc.
>
> These events can in fact happen with TC's, especially high power
> machines.
> Circuit Breakers can and do fail, and have led to deaths, panelboard
> blowup, building fires, and other such calamities. The powerful
> takeways in reading about electrical deaths and injuries is they tend
> to fall into the following categories:
> - Inadequate training for task at hand
> - Improper or defective tools for environment (voltages worked on)
> - Domino failures caused by a failure in one piece causing a much
> larger blowup/fire upstream closer to utility feed.
> - Insufficient knowledge of site conditions (does conduit have
> energized wires, where are panels fed from, prints not up to date,
> etc.).
> - Worker complacency ("I've worked 10 years and never been hurt"
> syndrome).
>
> It is not meant to be, but some of the OSHA reports read like
> something
> out of "Oliver and Hardy" or "Dumb and Dumber". It really hard to
> fathom how someone could make a series of "no-common-sense"
> decisions that lead to their demise...
>
> In doing research on this topic, suggest "Googling"
> - "Electrical Explosion"
> - "NFPA 70E"
> - "Flash/Arc"
>
> Also the below link has a very good table of flashover clearance in
> air
> of various voltages up to 262kV, useful for designing clearances in HV
>
> machines, since dimensions appear "reasonable" for dry sheltered
> space.
> Provided by the IAW union.
>
> http://www.uaw-dot-org/publications/skill/02/spring/spring02_7.html
>
> Particularly newbies should read and re-read the Safety FAQ on Pupman
> and read several of the incidents listed in links above. They are
> gruesome
> and make several clear points:
> 1. Your first mistake with HV could very well be your last.
> 2. Make sure your tools and meters (as VOM's) are in good working
> order. Many people have died because a VOM was defective and
> the victim assumed the power was off (rather then a bad meter).
> 3. Never be complacent around HV, reread rule one above.
> 4. _Learn from someone else's mistake, it very well could save your
> life_!
>
> Best Regards
> Dave Sharpe, TCBOR/HEAS
> Chesterfield, VA. USA
>
>