Safety info: electrical shocks

Date 08-30-2003 01:47

Hi Folks:

I just read this in a book I have called "Welding Essentials"...first time I had noticed the section.

1mA (that's milli-amp): noticeable tingle
5mA: very uncomfortable shock, possible burns.
50mA: considerable burns, possible respiratory arrest, uncontrollable muscle contractions, possibility of injury from falls, some possibility of death.
1 amp: possible cardiac arrest, severe burns, possible death.
10 amps: cardiac arrest, probable death.

Wow, a mere 10 amps is very likely lethal, my welder will push 160 amps, and I know many folks here typically weld with 2-3 times that much current. I'd say safety is a must, eh?

Anyone know how much voltage is typically required to overcome the resistance of skin?

Dave

By bzzzzzzzzzz (**)

Date 08-30-2003 03:15

Doesn't take very much...50 volts or so depending on conditions. Rememeber, it doesn't need to burn to a crisp to kill. Just stop the heart and yer just as cooked. Consider that welders use a high input voltage and often the operator is the one who decides how to supply that voltage to the unit. How many of the home workshop welders are protected by a groud fault receptacle? Most of those "shock charts" are there to enforce the idea that electricity needs to be respected.

By RonG

Date 08-30-2003 16:47

Dave,
Look up Ohms law do the math.

Its not that easy for your body to pass Amps but it can be done.

By DaveSisk (**)

Date 08-30-2003 21:45

Hey Ron:

I already know Ohm's law (v=ir)...and I'd do the math if I knew either the voltage or the resistance :-P

Dave

By RonG

Date 08-31-2003 02:57

Dave, I guess that came across wrong.

There is a differance between AC and DC in this issue. I'm sure your aware that AC can push more amps at lower voltage than DC.

Most AC welding machines do not produce enough votage to do you any harm unless you set your self up for it. Like standing in water or welding in the rain.

By brande

Date 09-06-2003 06:00

FWIW,
I have heard that the human body has 1 meg of resistance.
Good or bad, true or not, I don't know.
Any additional info appreciated.

Good Luck

brande

By kekoakeakane (*)

Date 08-30-2003 22:28

The general accepted resistance of your body to ground in dry conditions is 10k Ohms and is 1k Ohms in wet conditions (i.e. sweating). This means that a mere 50V is enough to cause possible respiratory arrest.