Re: Variac Safety

["Bernard G. Cleyet & Nancy Ann Seese" <georgeann@REDSHIFT.COM>]

Interleaved:

John Denker wrote:

> At 11:37 AM 12/1/00 -0800, Leigh Palmer wrote:

cut

> Read my lips:  if you connect an extension cord to banana clips and start
> fiddling, it is quite dangerous.  Such activity would not be tolerated in
> any research lab I know of.  The OSHA inspector would have a meltdown, and
> I can't say I'd blame him.

I was the safety officer and I never reported myself.


> And then... doing it in a teaching lab in front
> of unskilled students is beyond foolish.

Another version of the "suicide cable" (or cord)?

> Unless there is some tremendous upside (heretofore unmentioned), why would
> anybody want to mess with this stuff?  What needs to be done that can't be
> done with lower voltages and lower currents, in a properly enclosed chassis?
> (Transformer isolation or GFCI may help somewhat, but it is not in itself
> sufficient for safety, and does not, in the absence of a proper enclosure,
> meet code.)

My suggestion:  use the money for a three wire "Variac" on an isolation xformer,
and with the money saved use it to purchase a hi-end light dimmer and put both in
a box.

> There are people who get paid to move live 110+ volt wires around (notably
> utility company workers) but
>    a) there are highly trained and very methodical;
>    b) every once in a while one of them makes a mistake and is killed;
>    c) they don't leave live circuits lying around where bystanders can get
> at them.

When I was younger, I rarely cut the power when, say, replacing a socket or wall
switch.  Now I'm older, I still don't, but Ms. Gate Keeper stands near the
breaker.  Usually this is when cutting the power results in working in the dark.
The shocks are momentary diversions.

The first thing I remember when I arrived at Keele (UK) was being warned that the
line was 220 V and, therefore, to be careful.  Curious, I don't remember ever
doing a building wiring repair or using a suicide cable.

bc