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Re: [TCML] Fear of the NST

Every coil that I have made has used an earth ground as ground, and I have never had an "incident."  I agree with your point on #3, to a point---but you need to offer a safe alternative, especially since many young experimenters may be reading these posts.
Carl Bradley

“If you can't be a good example, then you'll just have to be a horrible warning.” 
--- Catherine Aird


   On Monday, June 18, 2018, 9:41:03 PM EDT, Gary Lau <glau1024@xxxxxxxxx> wrote: 
 I disagree with the advice:

The case of the NST is tied to RF ground and is full of high voltage RF
transients that you do not want feeding into your mains..  Unless the coil
is relatively low power and there is no alternate ground or counterpoise
available, you should not be connecting RF ground to mains ground.  I can't
think of any fault condition or inadvertent touch where having the NST case
tied to mains ground offers any safety advantage.

Regards, Gary Lau

On Sun, Jun 17, 2018 at 6:44 PM, Chris Boden <cboden@xxxxxxxxxxxxxxxx>

> Greetings Mr.Janota :)
> NST's are current limited and operate typically at a maximum of 15kV (with
> 12kV and lower being quite common as well).
> The typical max current output will be 60mA.
> What this means is it Most Likely, Probably.....Unusually....wont' kill
> you
> if you brush against the output, are a rigorously healthy adult, dry, and
> nontrivially lucky.
> This is as opposed to things like Pole Pigs at 10kVA or more (we have
> 100kVA pigs in the lab) with no current limiting which are reasonably
> considered to be fatal (it's not instant, and it hurts the whole time).
> There are also pulse capacitors (typical in our lab is 20kV to 50kV with
> 10kJ energies) those don't just kill you, they blow parts off. We have
> 400lb caps here that are in the "clean you off the ceiling with a sponge"
> levels of deadly.
> That's a long way from your NST, but the idea across the spectrum is the
> same. These toys are not for the emotional, impulsive, or stupid. They will
> hurt you the moment you don't respect them, and kill you if you're
> reckless.
> That's the point.
> There are millions of people who would like to own a powerful Tesla Coil.
> But very, very few get that far. The fundamental price to own a coil is
> simple, be smart enough to build one. It's not hard, but you have to do it
> yourself. Along that path you will have to learn hundreds of new things,
> foremost is safety and a healthy respect for HV. Consider how few people
> you know who have ever run a marathon. The rough number is often quoted as
> 1% of 1% of the people in America have ever run a marathon. The number of
> people in the history of the world who have ever successfully built a
> working Tesla Coil wouldn't fill a single run of the Chicago marathon. This
> is a very small community.
> To the average person Electricity is composed mainly of magic. It's
> dangerous and terrifying. In reality, it's just science. The mechanisms of
> electrical power have been pretty well worked out by people far smarter
> than me. We can build chips at the nano-scale with billions of wires only a
> few atoms wide carrying energies less than a mouse's fart, and we can
> wrangle million-volt power lines across the desert. But to the average
> person they understand as little about how the power gets in their computer
> as they do about what actually happens when they flush the toilet.
> You should have a respectful, healthy fear of HV, but not a crippling one.
> It's not magic, and it won't jump across the room and bite you. Some simple
> things to remember will help you a lot.
> 1. Keep the plug in your pocket when you're working on the NST. If the plug
> isn't in your pocket, then don't touch it.
> 2. 15kV with a beginner wants a safe radius of 2 inches to anything, and 3
> feet to anything that's alive. Keep the HV conductors 2 inches from the
> case and you're not going to have any problems.
> 3. GROUND THE CASE OF THE NST. The bottom-center hole on a US outlet (the
> mouth of the face) is Ground. This should connect to the uninsulated lug on
> the side of the NST. The NST will have two big insulated lugs (the HV
> terminals) two smaller insulated lugs right next to each other (the LV
> terminals), and one uninsulated lug that just looks like a bolt sticking
> out the side....that one is the ground.
> And lastly, while most of the people here would never admit it (and
> certainly never publicly), the vast majority of us have been bit at some
> point because we did something stupid and got a hard lesson in pain. I've
> been bit a few times and thankfully, by sheer dumb luck I survived them,
> so far.
> Good luck :)
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