Mains safety, was: Setting up a VAXstation
Mr Ian Primus
ian_primus at yahoo.com
Mon Oct 8 13:02:03 CDT 2007
> Secure the breaker in the off position, lest someone
> come by and
> think that it's been tripped and decides to do you a
> favor. In
> industry, this meant locking the disconnect box with
> your lock and
> tag. If there are fuses in addition to a
> disconnect, pull the fuses
> and put them in your pocket or tool pouch--don't
> leave them by the
> disconnect box.
> In residential installations, this may not be
> possible, so I'll use
> good old duct tape over the breaker handle. Not
> perfect, but better
> than nothing.
Hehe, that doesn't always work... Several years ago I
did work for a school system installing network wiring
and nice metal wall mounted tracks for it to run in
(Wiremold). Some areas included the installation of
power as well. Well, the guys and I were installing
the power section of one of the labs, so we went down
and shut off the breaker. Now, this breaker panel is
in a utility room, and it's a household style breaker.
No "lock-out" system available. So, we used what we
normally used. Black electrical tape covering the shut
off breakers, the panel taped shut, and a sign taped
to the panel warning that breakers #X and #Y were shut
off to install outlets, and were not to be turned on.
Go back to the room, and test the voltage with the
meter. Dead as a doornail. So, work progresses, wires
threaded through metal tracking, installing outlets,
when, as we were pulling some wire through a hole, the
bare ends dragged against the metal, creating a heck
of a flashbang. Scared the hell out of us. We went
back to the panel, only to find that the sign and the
tape were gone, and the breakers switched back on.
(And of course, one of the previously shut-off
breakers was now tripped from being shorted out.)
Now, this work was being done in the summer time - no
students. There were some janitors and other people in
the building working on things, but that's about it.
We never did figure out who turned the breaker back
on, or why in the hell they did it. And the sad thing
was, this panel was actually labelled as to what the
breakers did. All anyone needed to do was pop by the
room number marked on the panel to see if someone was
still working on the wiring.
Since we couldn't very well post guards on the panels,
tape and signs were the best we could really do, save
for taking the panel apart and removing the breaker.
So we would always be sure to have the wiring shorted
out completely at our end, and leave it that way until
all work was completed. Our hope was that if some fool
did turn the breaker back on, it would immediately
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