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Re: [TenTec] Electric safety

To: tentec@contesting.com
Subject: Re: [TenTec] Electric safety
From: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Reply-to: geraldj@weather.net, Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Thu, 18 Feb 2010 17:25:00 -0600
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
On Thu, 2010-02-18 at 16:05 -0600, Pumbaa wrote:
> That is one thing (HV) I did consider when I decided to buy the Ameritron 
> ALS-1300 Solid State Amplifier.  The other is the lack of used Centurion 
> amps for sale.
> 
> Tom AG8K
> 
While the mark left by high voltage may be small, a low voltage supply
can cause amputations, especially a lead acid battery. 12 volts at a 100
amps through a wedding ring can amputate that finger cleanly. That much
current through a metal watch band can do a lot of damage too.

For that matter when shock is involved, the "ordinary" 120 volt circuit
is more deadly than high voltage in most situations. That's because high
currents stop the heart, then when you fall down the bump is a pretty
good heart starter. But 120 volt shocks often put the heart into
fibrillation, and in that operating mode the heart's reflexes are
satisfied though it pumps no blood. 4 or 5 minutes and you're brain
dead. A few more and your dead all over. You can only be brought of
fibrillation with a defibrillator to give a massive short shock to stop
the heart and let it bounce into a normal rhythm again.

True, the burns from a 7 KV power line are bad but I had several clients
who survived those and several families of those shocked by tools
supplied with 120 volts that didn't survive. And I had to explain why in
my consulting business over the past several decades.

High current and any voltage demand some attention and care. Even if the
shock isn't severe enough to cause major injury or heart problems the
speed with which the shock can cause your arm muscles to contract and
you to extract your hand from the radio can cause the back of your hand
to loose much skin as it hits stuff on the way out of the radio.

Good safety rules require no watches or rings when working with live
electricity at any voltage. Good safety rules require you to not work on
high voltage apparatus with the power on, and after the power is off AND
thoroughly disconnected in a way that NO ONE can apply power (like pull
the plug and put it IN your pocket) short the power supply with a metal
rod on an insulating handle, and park it there until you are finished
with the work. E.g. short it and keep it shorted. And there's the old
rule, one hand in pocket, one hand in circuit. That minimizes the
current paths through the heart, but you can still jump fast and high
without control and the bounces can get you into deep trouble, like
landing ten feet from the foot of the ladder you were on.

73, Jerry, K0CQ

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