Re: Can we talk safety for a moment?


Cliff Carrie
 

I was a support specialist on large mainframes in the 1960s and 70s. The DC supply outputs were less than 2 volts, but at over 100A. Rings and watches were a no-no, because if you shorted a power bus with one, the ring could heat or even melt unless the overcurrent crowbar circuit triggered. The hot jewellery could cause a traumatic or an eventual surgical amputation. The SCR crowbar circuits shorted the supply output and blew input breakers, so they were normally good protection. I saw one triggered by a piece of bare AWG 30 wire falling across a bus. The system dropped power, but the wire (which should have vaporized) was barely tarnished. That's FAST protection. I still never wore rings or watches. We often had to troubleshoot with power on.


Regards, Cliff Carrie
________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Glenn Little <glennmaillist@bellsouth.net>
Sent: Monday, February 19, 2018 5:10:05 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Can we talk safety for a moment?

It is not necessarily the contact of the ring with an energized circuit
that will cause trauma.
The recoil from a shock with the ring catching on something that will
possibly forcibly amputate the finger.


Glenn


On 2/19/2018 3:41 PM, Richard R. Pope wrote:
David and et al,
For those of us who will not remove their wedding ring/s you can
thoroughly wrap them in adhesive tape. There must not be any exposed
metal and two layers are better than one. Also we were taught in the
AF that if we had to touch a piece of equipment to use the back of our
hand or at least an open hand. A lot less chance of being grabbed.
GOD Bless and thanks,
rich!

On 2/19/2018 8:20 AM, David Berlind wrote:
Whoever wrote "remove jewelry".... I left that one of my pre-work
list. I'm
adding that. Also, even though my bench has a rubber mat on it, I
really
like the idea of putting rubber on the floor. Right now, I stand (with
rubber soled shoes) when I'm working on a live amp because I don't
want my
ass to help complete a circuit that goes through my wooden chair to the
floor. Does anyone have suggestions on where to acquire a relatively
large
but thin sheet of rubber that I can put down under my bench and chair.

On Mon, Feb 19, 2018 at 7:43 AM, jafinch78 . <jafinch78@gmail.com>
wrote:

On Mon, Feb 19, 2018 at 04:35 am, John Griessen wrote:

I don't remember such a rule in the 2004 elec code
Yeah, I've been grilled with implementing systems and methods to
meet and
exceed U.S. Regulatory CFR, USP/NF, EP, NIST, or whomever dealing with
Standard's and... man... the self regulatory industries like law
enforcement, health care and certain I guess union attorney regulated
agencies rackets can override codes if no one enforces.

My recollection is still National Code to bond meter box to ground. I
even have a wire that was cut by and not re-attached by them, though
something to do with the one Utility Company... Indiana Michigan
Power in
my investigation. Code Inspector said the same thing that is unique to
them if I recall correctly.








--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@arrl.net AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"

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