On Wed, 7 Apr 2010 12:31:47 +0000 (UTC), Jules Richardson
wrote:

On Tue, 06 Apr 2010 22:07:33 -0400, clare wrote:
As for safety - AC and DC are relatively equal as far as shocks are
concerned - if 12 volts DC does not give a shock, 12 volts AC won't
either. The only difference is a DC shock is a "single hit" while AC
is a "buzzzz" WHich is more dangerous? Since AC hurts more, I'd say DC
is the more dangerous - easier to ignore??????

Lots of old railroad engineers have told me that DC was far worse because
it can make muscles contract - and then you can't let go of whatever it
is that's causing the shock. Whether there's truth in that, I'm not
sure...

I don't know how many 240V AC shocks I've had over the years when I lived
in the UK, but certainly quite a few. I'm yet to get zapped by US
power... :-)

cheers

Jules
The DC muscle contraction is true - when the current gets high enough
to cramp your muscles on AC it reverses and you have a chance to let
go - On DC it is constant polarity and your muscle never relaxes.