# Re: How do you get the guts (or stupidity) to draw a spark ?

```Subject:  Re: How do you get the guts (or stupidity) to draw a spark ?
Date:   Tue, 10 Jun 1997 07:14:55 +0000
From:   "John H. Couture" <couturejh-at-worldnet.att-dot-net>
To:  Tesla List <tesla-at-pupman-dot-com>

At 12:37 AM 6/8/97 +0000, you wrote:
>Subject:  How do you get the guts (or stupidity) to draw a spark ?
>  Date:   Sat, 07 Jun 1997 09:35:33 -0500
>  From:   Shawn Collins <rubidium-at-worldnet.att-dot-net>
>    To:   tesla-at-pupman-dot-com
>
>
>I have seen many pictures on various pages of people drawing sparks to
>metal
>objects they are holding on to. At what frequency of operation is this
>safe,
>and how  did you ever get up the guts to try it ? I know the primary
>side
>can kill, but according to skin effect formula (which I can't find right
>now) at 170kHz the current is only .06" deep.
>
>Thanks,
>Shawn
>
>------------------------------------------------------

Shawn -

Fortunately the RF currents of Tesla coils do not pass thru the human
body
but stay only on the surface. If they did pass thru the body most
coilers
today would be dead because these currents are large. Note that the skin
effect equations are only for metal conductors.

The human body can only feel or react to AC currents under a few
thousand
hertz. These low frequency shock currents can pass thru the body and
cause
the heart to pump erratically which can cause death. These currents can
also
cause the muscles to contract around the lungs and cause death. CPR can
save
lives.

RF currents can cause damage to the skin by sparks and arcs resulting
in
burns but not shocks. If you feel a so called shock it is probably a 60
Hertz current. These currents are in both the primary and secondary TC
circuits. These 60 Hertz currents in the secondary circuit are usually
very
small but can be large enough to be fatal. The amount of current is
dependent on the grounding network of the Tesla coil, house service, and
power company system. Never come in contact with ground if you insist on
playing around with the energized secondary terminal.

The bottom line is that the low frequency currents in both the primary
and
secondary TC circuits can be fatal. The amount of danger is inversely