wrote in message
On Mon, 11 Nov 2013 17:47:28 -0500, "Robert Green"
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OK - that's fair enough. I'll admit I did not consider that when I
replied.
I've just been taught not to trip breakers unless it's absolutely
necessary
as they have a finite number of fault cycles before they fail. That
means I
wouldn't have seized upon that method to diagnose a fault.
The cost of a breaker IF it failed may still be a bargain if it finds
the problem in 2 minutes instead of spending 2 hours - - -
That's probably true, although it's advice for the electrically savvy. The
thing I had a hard time researching was how many fault cycles a breaker is
good for. The answers I saw read from "replace it after four trips" (too
conservative, IMO) to "it's good for 100,000 trips." (I think somewhere in
between those two estimates is correct - but where?)
Clearly the latest breaker designs are far more resilient than breakers of
50 years ago, and I only found one instance of a person claiming a breaker
had failed closed. The nuke sub breakers that my dad worked with that
failed often were circa 1963 and were very special-purpose units. Made to
precise government specs, too, and built by the lowest bidder. (-:
My experience is with the "grunt and crank" method of shutting off
breakers
one by one (as Nate recommended) and comes from dealing with X10
equipment
issues where tripping a breaker deliberately usually doesn't gain
anything.
X10 troubleshooting involves looking for sources of noise or signal
attenuation.
In this case, however, I will gladly concede that it would save time in
hunting down a likely source of the problem. Still, I think it's a very
long shot that the ground shunt on the meter was missing or had failed.
Therefore it would NOT have been the first place I looked, that's for
sure.
I've seen it numerous times.
I defer to your experience but wonder why it's so common? Apparently the
instructions for such devices call out the need for a ground shunt of some
sort and you'd think water company personnel would be trained to deal with
it after the first dozen times someone got shocked to death dark humor
alert.
And how would repairing ground continuity through the meter, if there
was
none, make the voltage in the pipes go away? No properly functioning
device
should be dumping enough current into the ground to be detectable at
multiple faucets, AFAIK.
I've had phantom voltage from a cable adaper (cable tv) put enoug
voltage into a TV to give a pretty nasty "tingle" that totally went
away when the TV cable was properly grounded.
I still contend that there's a problem if grounding alone cures it. There
shouldn't be any current leakage in a properly designed and functioning
system, should there? I, too, have been zapped just touching the CATV line
and something metallic at the same time. Considering the skill of the last
two cable jockeys that Comcrap er Comcast sent out, it wouldn't surprise me
if they did something wrong enough to energize the CATV cable with enough
juice to be dangerous.
It will pull the water line to ground potential. It only takes
MILLIAMPS of leakage to give a tingle.
But even milliamps of current leakage is impermissible, AFAIK, and that's
why wet areas are now required (when doing new work) to be protected by
GFCIs in most cases. (Hope that's broad enough for the NDBF's.) You can
be
electrocuted if you manage to get those milliamps running across your
chest.
Even if you repaired an open ground shunt at the meter, wouldn't you
agree
that something's still wrong with the wiring?
Not necessarily. A bit of leakage is almost considered normal on some
electrical equipment - and it may not even BE real leakage - it could
be inductive or capacitive inductance
What types of equipment would do that?
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Years ago, we had a car club in an old chicken barn, which we had clad
with steel siding. We had poured concrete floor in part of it - with
fence wire for re-enforcement. In the "club room" we had a CB radio
base station sitting on top of an old refrigerator.
Every once in a while one of the guys would report getting a "small
shock" when opening the door. We didn't think much of it, untill one
day I was doing some grinding with a hand grinder on a body repair
when my knee touched a spot where the fence wire just poked through
the rough concrete job - and I got a REAL zap. I thought there was a
problem with the grinder, untill I tested it and everything was OK.
THEN I started looking. Ends up the power transformer on the base
station had smoked, and it was pumping 115 volts out the antenna,
which under certain conditions (like rain or heavy dew) shorted with
fairly high resistance to the metal siding - which connected to the
fencewire in the concrete - and found ground through me to the
grounded grinder.
Ouch. In the X-10 world, people unfamiliar with electricity would often
modify their RR501 transceiver modules to try to improve reception by adding
a longer aerial. Unfortunately the design of the unit used capacitive
coupling to attach the antenna - a small copper pad on the inside of the
case that coupled through the plastic to a small copper pad on the outside
that attached to the antenna. People would simply attach a wire to the
inner pad not realizing that it was live at 110VAC. This was a two-pin
device, too. A surprising number of people zapped themselves trying to
extend the (pitiful, generally) range of those devices with an antenna mod.
I burned up an HP Laserjet's control board using an unpolarized three-wire
adapter. I saw a quite respectable spark when I plugged in the printer
cable between the properly connected PC and the improperly connected
Laserjet. No magic smoke escaped, so it was probably an IC or something
relatively smoke-free. (-: Just a dead Laserjet at a time when they cost
*real* money - $2K+ for the LJII with accessories, IIRC.
When I directly grounded the fence wire, it popped the fuse in the
radio, and the voltage went away.
From what I've been reading, many "tingle" situations are due to internal
defects or failures in items that are connected to ground through means
other than the grounding pin of a grounded receptacle. Strapping pipes with
materials that can corrode from exposure to moisture or cause a galvanic
reaction was an idea whose time has come and mostly gone, and for a number
of disparate reasons.
I think I will take my own advice and review and perhaps rewire any
remaining pipe clamp grounding equipment in the house. They may be
grandfathered into the code, but both my grandfathers are dead and I don't
want to join them. (-:
If you smelled gas in your basement would you go around looking for the
source or call the gas company? Can the average homeowner really compete
with experts who are equipped with sophisticated gas sniffers to detect
the
source of even the smallest amount of gas? I know what I would do (and
have
done). Call the pros because such cases aren't just home repair issues,
they are potentially life and death ones.
Another point to note is *why* would a water meter ground suddenly fail
and
be repairable by jumpering? It just doesn't seem to me to be the first
place to look in a situation like this because it just seems so unlikely
that the meter shunt would suddenly go bad. I would look to recent
plumbing
repairs or devices hooked into ground via the water pipes that have
failed
and are dumping current into the supply pipes.
Have you looked at what often passes as the meter shunt?
I'd have to dig up the front yard. I have *never* seen a water meter inside
any home in the US in my 60 plus years, although I am sure they exist. Is
that a Canadian thing because of the colder temps?
A clamp made of iron strapping wrapped around the pipe, with the
copper cable bolted to it. Condensation keeps it damp to wet, and the
strap corrodes off the pipe - you get a ground failure. Not suddenly,
but eventually. One day it gets bad enough that it doesn't ground any
more ---
I already had a leak coming from galvanic action from a plain old pipe strap
so I don't doubt it's probably a good idea to check stuff like that yearly
or so. Turns out they were copper plated steel straps and mechanical wear
took out the coating and Galvani's discovery did the rest.
My friend added one mo
$100 per hour
$125 per hour if you watch
$150 per hour if you tried to fix it yourself
$200 per hour if you tell us how to fix it (!!!)
Can you imagine a time where there was no electricity anywhere? It's kind
of neat that so many terms we use are actually created from the names of
great inventors:
Scientists whose names are used as SI units
http://en.wikipedia.org/wiki/List_of..._as_SI_unit s
Base units
a.. André-Marie Ampère
b.. William Thomson, 1st Baron Kelvin
Derived units
a.. Henri Becquerel
b.. Anders Celsius
c.. Charles-Augustin de Coulomb
d.. Michael Faraday
e.. Louis Harold Gray
f.. Joseph Henry
g.. Heinrich Hertz
h.. James Prescott Joule
i.. Isaac Newton
j.. Georg Ohm
k.. Blaise Pascal
l.. Werner von Siemens
m.. Rolf Maximilian Sievert
n.. Nikola Tesla
o.. Alessandro Volta
p.. James Watt
q.. Wilhelm Eduard Weber
--
Bobby G. (Gravity - as in "pulling 10G's" - also finance "I owe him 20G's)
humor alert