Ok, I'll be the curmudgeon...
Is this really a problem in practice?
Most people I've known who worked around electrical mains etc assumed
the worst at all times and it isn't all that difficult to protect
against as one works.
I realize one can infinitely invoke "better safe than sorry!", "an
ounce of prevention...!"
<OBLIGATORY FUNNY STORY>
Except maybe that one guy at Harvard who came to replace what turned
out to be a 100+ year old, home made, "breaker" which fed our machine
room which was hidden in a narrow dark hallway winding around our
machine room behind an unmarked metal, locked doorway. I had no idea
it existed but we had no power so I called for help.
It was just a single copper bar about the size of a small candy bar
tensioned into hot clips. Probably 400A but who remembers.
He removed the old one confidently enough, grabbed the new one with
rubber-handled pliers and gloves and...
Him: Have you ever played football?
Me: Actually, yes, I have, why?
Him: If something doesn't look right when I put this thing in just
tackle me clear of it as hard and as fast as you can.
Me: Um, ok.
It all worked out fine and I wrote a memo that maybe Harvard could
spring for a proper $500 breaker box?
</OBLIGATORY FUNNY STORY>
... and my "funny" story.
We used to live in San Jose. There was a large heat-wave, and much of SJC lost power because of A/C load, etc. Anyway, my wife and I go and camp in one of the office conference rooms for a few days because the office still has power and A/C.
Eventually PG&E claims that power is back on our street, so we drive back to San Jose and... no power. I flag down a passing PG&E truck and ask if they know when it will *really* be back. Lineman says that it is. I say it isn't. He says it is. I say it isn't.
He gets annoyed, opens up the pedestal box and sticks a meter in it, and agrees that I have no power. He then sticks the meter across the 800A fuse, and discovers that the fuse blew.
"Ah. I can fix that fer you..." he says, and goes to the back of the truck... "Doh. I'm out of 800A fuses. Um.... er.... well, here is a 6,000A fuse, that'll do..."
I briefly question the logic of this (presumably the lines in the ground are sized somewhere around 800-1,200A), but he says that this'll do, and he'll come back in the next few days to replace it. I lived there for another 8 or so months, and it was never replaced, but, well,... not my wires, so, um ¯\_(ツ)_/¯ I guess...
W
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-Barry Shein
Software Tool & Die | bzs@TheWorld.com | http://www.TheWorld.com
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