Anyone with Roger's Lite accounts?

[Mike Kallies]

On 4/18/06, Lennart Sorensen <lsorense-1wCw9BSqJbv44Nm34jS7GywD8/FfD2ys at public.gmane.org> wrote:
...
> I mostly see GFIs installed as part of the outlet in bathrooms and
> outdoors, while in europe I have often seen a single GFI installed on
> the main incoming 3 phase line to a house, so everything is covered at
> once.  Of course given I lived in Denmark, which until very recently
> didn't believe in grounded outlets at all, having the GFI protect
> everything was probably a good idea.  It seems the theory in north
> america has been that if the hot wire shorts to the case of something,
> the case is grounded, so it will overload the breaker/fuse and turn of
> the power, before any person gets a chance to touch it, and anything
> that isn't grounded is supposed to have a fully insulated case so it
> can't possibly conduct power to the user.

Yeah, those are the devices, GFI(C)s ground fault interrupt
(circuits).  They make you replace your ungrounded outlets with the
GFIC if you need to inspect an old house.

The grounded case will protect you by offering much, much less
resistance to ground than your body.  It doesn't matter if the fuse
blows.    E.g. if a neutral shorts to the case after the load, the
fuse won't blow at all, but the case will be live.

If you manage to reduce your resistance sufficiently, like holding
your water faucet while fishing your wet corded razor out of the sink,
then only a GFIC can save you.

The GFIC is a pain in the butt with big motors because the motors
temporarily unbalance the current by storing the power in momentum. 
...Although I've used a conventional GFIC with an outdoor lawn mower
and haven't had any problems.  Washing machines and fridges might be
the only things big enough to cause problems for them.  Which is good
becuase an outdoor electric lawnmower without a GFIC always seemed
like a dumb idea to me.

The point is that you can't use them _everywhere_, there are limits.

I'm pretty sure I've seen plastic device boxes used in Canada, I don't
know anything about them.  They seem simple enough, but who knows what
the codes say :-)


-Mike
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