Re: Shock Warning

Being in a rush, I 'forgot' :) to ground one end of my stepper
cable. it was only 35 feet long and coiled on the floor, but when I
inadvertanly touched the darn shielding ...

Well, let me say, after I stoped shakeing, I got out the tape for one
end, and grounded the other PDQ.

I'm not sure if I should say it was a shocking experiance, or that I
was shocked to find that much juice in the wire.

Dave

--- In CAD_CAM_EDM_DRO@y..., "JJ" <jj5412@e...> wrote:
> Electronic Communication - Robert L. Shrader
> Pg. 759-760
>
> 35-11 Electrical Dangers
>
> Electric shock can range from 1mA for the threshold of feeling, to
5mA
> for decided pain, to 10mA for the beginning of arm paralysis, to
30mA
> for stoppage of breathing and possible death, to 75mA for
ventricular
> fibrillation (discoordinated heart beats) and probable death. With
4A
> the heart may stop but may start again when current ceases. Above 5A
> causes tissue burning, but may not be fatal if vital organs are not
> involved.
> A 5 to 10mA shock can cause a violent reaction that may throw a
person
> backward and possibly against some hard object or off a ladder,
which
> may cause injury.
> Some appropriate skin contact resistances are: finger touch, dry,
50kR,
> wet, 5kR; grasping wire, dry, 15kR, wet 5kR; holding pliers, dry,
5kR,
> wet, 2kR; foot to wet ground through wet shoe, 5kR; hand in water,
300R.
> Thus, standing on damp ground with wet shoes, holding a pair of
pliers,
> and touching a hot wire, the resistance to ground is perhaps 10kR.
From
> Ohm's law, E=IR, the voltage to produce a sharp pain would be .005
x
> (10,000) or 50v. If the hand is perspiring, the voltage would be
only
> 35v. Across 120v ac enough current might flow to produce respiratory
> paralysis because after a short time the resistance of the body
> decreases, increasing the shock current.
> The path of the current determines how lethal a shock may be.
Across a
> hand or up one arm may not be lethal, whereas across the body and
heart,
> or involving the brain or backbone areas, shocks may be very
dangerous.
> One should always make sure not to be grounded when working with any
> electrical equipment. (See also Sec. 17-32)
> If someone is subjected to electric shock, the electricity should be
> turned off before touching the person. If this is not possible, the
> person should be dragged off using dry clothing or pushed away from
the
> circuit with sticks of dry wood or other insulating materials. Be
very
> careful not to get in the electric current too! If breathing has
stopped
> mouth-to-mouth resuscitation must be given immediately. If there is
no
> carotid (throat) pulse, CPR (cardiopulmonary resuscitation) must be
> started at once. Everyone should be familiar with CPR and be able to
> give it. Contact the Red Cross for CPR instructions and training.
>
> Regards,
> JJ
>
> Be Kind, Be Careful, Be Yourself