Anything likethis happen to anyone?? As I worked on my water heater, I
happened to touch the copper pipes and to my surprise I jumped!!! Not enough
to kill me but it let me know something is wrong here. Then I changed my
washer and dryer in the new room and the same thing there. I touched the
back of my washer and ZAP got me again.. Any insight on this shocking
situation anyone please?????

larry

Shouldn't happen. The water pipes are often used as a ground, but since
they are grounded, you can't get a shock off them. But, maybe they aren't
grounded. Is there a jumper around your meter, or any plastic in the
system?

I suggest that you ascertain there is voltage between the water pipes and a
true ground. Assuming there is (if there isn't, then you are hallucinating)
then shut off all the breakers and see if there is voltage. Assuming there
isn't, turn them back on one at a time and see what circuit energizes them.

With that knowledge, you can probably fix it.

On Tue, 23 Mar 2004 01:26:37 GMT, "Laurent Doiron"
wrote:

Anything likethis happen to anyone?? As I worked on my water heater, I
happened to touch the copper pipes and to my surprise I jumped!!! Not enough
to kill me but it let me know something is wrong here. Then I changed my
washer and dryer in the new room and the same thing there. I touched the
back of my washer and ZAP got me again.. Any insight on this shocking
situation anyone please?????

larry


You have two problems...

#1 There is current on the ground leg of some device in your home.
Another poster already gave you an excellent method to determine where
the power is coming from.

#2 You water pipe is no longer grounded. I'm going to guess here
(bad thing to do on usenet) and say that you have an older home. It
was at one time common practice to use the water line as a grouning
conductor. At some point in time a piece of your water pipe was
replaced with plastic so now that grounding function is no longer
there. I would, or have an electrician, install an approved ground
rod and move your ground to the new rod instead of the water pipe.

Steve B.

You have a bad short that is dangerous and costing you alot of money in
wasted electricity to ground. Call a pro.

1) All connections to water pipes must be to remove
electricity from those pipes; never to dump electricity into
those pipes. Pipes are no longer acceptable as ground - earth
or safety. Connection to earth ground must be via dedicated
earth ground connector - and not via water pipes.

2) Volts500 provided a good summary of grounding for human
safety. Use this as a checklist to begin or identify
necessary household corrections: in the newsgroup
alt.home.repair entitled "Grounding Rod Info" on 12 July
2003 or http://tinyurl.com/hkjq

3) Post 1990 code requires earthing at the breaker box.
Something like two in 10 older homes I have observed don't
even have minimally acceptable earthing - per 1950
requirements. Suggest you inspect for or hire an electrician
to upgrade your household earthing to meet post 1990
requirements. This is not a casual recommendation.

4) Bottom line - your building has a problem directly
traceable to human failure. Fix the building now so that
humans are not harmed later either due to electric shock or
even worse (and it is a possibility) building explosion. Yes,
the problem could even be that serious. Don't screw around
waiting for the best newsgroup response. They are found in
the Yellow Pages.

Laurent Doiron wrote:
Anything likethis happen to anyone?? As I worked on my water heater,
I happened to touch the copper pipes and to my surprise I jumped!!!
Not enough to kill me but it let me know something is wrong here.
Then I changed my washer and dryer in the new room and the same
thing there. I touched the back of my washer and ZAP got me again..
Any insight on this shocking situation anyone please?????

larry

"Laurent Doiron" wrote in message
...
Anything likethis happen to anyone?? As I worked on my water heater, I
happened to touch the copper pipes and to my surprise I jumped!!! Not
enough
to kill me but it let me know something is wrong here. Then I changed my
washer and dryer in the new room and the same thing there. I touched the
back of my washer and ZAP got me again.. Any insight on this shocking
situation anyone please?????

larry

Yes, and it was caused by one of the elements in the electric water heater
being shorted and feeding enough electicity to the water in the unit to
cause a shock at the washer/dryer and anything else that was grounded to a
water pipe. Also a big jump in the electric bill the month before it was
figured out.

Yes, and it was caused by one of the elements in the electric water
heater
being shorted and feeding enough electicity to the water in the unit to
cause a shock at the washer/dryer and anything else that was grounded to
a
water pipe. Also a big jump in the electric bill the month before it was
figured out.

What kind of short was it that didn't trip the breaker?
If you pipes were grounded why would you get a shock off them? Your
resistance has to be thousands of times higher than the water pipes, so if
there was some wierd short that only allowed a couple amps, 99.99% of it
would go through the pipes when you touched them.

This doesn't make any sense to me. Can anyone explain it?

Toller wrote:
What kind of short was it that didn't trip the breaker?
If you pipes were grounded why would you get a shock off them? Your
resistance has to be thousands of times higher than the water pipes, so if
there was some wierd short that only allowed a couple amps, 99.99% of it
would go through the pipes when you touched them.

This doesn't make any sense to me. Can anyone explain it?

Plastic pipes? The current would then be through the water, not the pipe.

You'd notice a shock when you were grounded yourself, say on a basement floor,
and touched metal in contact with the water.

Continuing current would discharge through the water to grounded devices in
contact with the water, running up the electric bill. It reduces the heating
requirement in the same amount, though. But it needn't be a breaker-blowing
current.
--
Ron Hardin


On the internet, nobody knows you're a jerk.

Ron Hardin wrote:
Toller wrote:

What kind of short was it that didn't trip the breaker?
If you pipes were grounded why would you get a shock off them? Your
resistance has to be thousands of times higher than the water pipes, so if
there was some wierd short that only allowed a couple amps, 99.99% of it
would go through the pipes when you touched them.

This doesn't make any sense to me. Can anyone explain it?


Plastic pipes? The current would then be through the water, not the pipe.

You'd notice a shock when you were grounded yourself, say on a basement floor,
and touched metal in contact with the water.

Continuing current would discharge through the water to grounded devices in
contact with the water, running up the electric bill. It reduces the heating
requirement in the same amount, though. But it needn't be a breaker-blowing
current.

Frankly, I don't think that would happen unless the water heater shell
was also ungrounded. And remember guys, the OP said he "touched copper
pipes" around the heater, which lessens the possibility that plastic
piping was involved, huh?

And how about those laundry machines? Unless they were both unplugged
from their outlets they should have been grounded too, so something had
to be seriously wrong with the grounding of the electrical system in
that building.

I vote for broken main grounds to both the main electrical panel and the
plumbing, probably at a point where just one conductor was doing both
jobs. That would let all the electric wiring grounds and neutrals and
the entire plumbing system were free to be driven off ground by a faulty
element in the wather heater, or some other device with a slight amount
of internal electrical leakage.

If the heater tank was properly grounded, I'm hard pressed to believe
that the electric field strength at the piping ports would be large
enough to put enough voltage on the water in plastic pipes to be felt,
were plastic piping used.

Comments?

Jeff

--
Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"My luck is so bad that if I bought a cemetery, people would stop dying."

According to Jeff Wisnia :
Ron Hardin wrote:
Toller wrote:

What kind of short was it that didn't trip the breaker?
If you pipes were grounded why would you get a shock off them? Your
resistance has to be thousands of times higher than the water pipes, so if
there was some wierd short that only allowed a couple amps, 99.99% of it
would go through the pipes when you touched them.

This doesn't make any sense to me. Can anyone explain it?

Plastic pipes? The current would then be through the water, not the pipe.

You'd notice a shock when you were grounded yourself, say on a basement floor,
and touched metal in contact with the water.

Generally speaking you're not going to get much current through water with that
small a cross-section. "Feelible" _maybe_.

Continuing current would discharge through the water to grounded devices in
contact with the water, running up the electric bill.

But not by much.

It reduces the heating
requirement in the same amount, though. But it needn't be a breaker-blowing
current.

The real issue is that the copper pipe may well have a full hot short, but the
person is only getting a minor tingle because his shoes/socks are moderately
good insulators, and dry concrete isn't that good a conductor either.

If he sprayed salty water on bare feet, stepped on the concrete and touched the
pipe, it may blow him through the wall.

This is a very hazardous situation. The level of jolt _may_ depend only
on how well the other end of you is connected to ground.

I remember getting a tingle from the frame of a radial arm saw I had just
bought at an auction and plugged in.

Stupid me. I tried to confirm it by touching the saw _and_ the cover attachment
screw of a nearby outlet.

_Whammo_. That hurt!

The ground wire in the RAS plug had come adrift from the third prong and
was contacting the hot wire. The whole case was full live. But it appeared
only a minor tingle because I didn't have good conductivity to the floor.
But when I touched a grounded screw... Whap!

[I learned my lesson. If in doubt, use a voltmeter. Don't use _you_.]

Frankly, guys, if I was in shoes on a concrete floor, and just touching
a pipe gave me a tingle, I'd kill the house power _immediately_ and
get everyone out of the house.

Then, I'd get out the voltmeter, and turn on the power again. Then carefully
(touching as little as possible) start measuring voltages between "supposed"
grounds to figure out what's wrong.

And how about those laundry machines? Unless they were both unplugged
from their outlets they should have been grounded too, so something had
to be seriously wrong with the grounding of the electrical system in
that building.

Dryers aren't hooked up to the plumbing. Washers often don't have
electrical conductivity to the plumbing either (the hoses are rubber -
our code requires a bonding strap from case to pipe, but it's often omitted...)

Water heaters cases don't necessarily have good electrical connectivity to the
plumbing, because the teflon tape or pipe dope _may_ interrupt the electrical
path. Plastic certainly would. Rusty metal unions might too.

I vote for broken main grounds to both the main electrical panel and the
plumbing, probably at a point where just one conductor was doing both
jobs. That would let all the electric wiring grounds and neutrals and
the entire plumbing system were free to be driven off ground by a faulty
element in the wather heater, or some other device with a slight amount
of internal electrical leakage.

The main thing we know is that the pipe isn't grounded. It _may_ or
may _not_ be connected to the electrical system ground. If it is, the
electrical system ground isn't connected to the dirt (or whatever the
other object the OP was touching when they got the tingle).

Could even be that the pipes are well grounded, but the water heater
(he was leaning against it when he touched the pipe, right? ;-) is
ungrounded and is getting a bit of stray voltage because a cracked
insulator, and it was otherwise diminished by the paint coating.

Etc.

If the heater tank was properly grounded, I'm hard pressed to believe
that the electric field strength at the piping ports would be large
enough to put enough voltage on the water in plastic pipes to be felt,
were plastic piping used.

Forget electrical field strength. You won't feel it at these frequencies
and power levels.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

The real issue is that the copper pipe may well have a full hot short, but
the
person is only getting a minor tingle because his shoes/socks are
moderately
good insulators, and dry concrete isn't that good a conductor either.

That begs the issue. It is only possible if the copper pipe is not grounded
(otherwise it would trip the breaker), but if it isn't grounded why would he
get a shock off the washing machine (or whatever machine it was)? The
chassis of the washing machine IS grounded, so you would trip the breaker
there also.

It must be that the copper pipe is somehow live, and neither it nor the
whole electrical system are grounded. It would seem like he would have to
know that somehow it that were the case. For instance, if my ground was
broken my dryer and overn wouldn't work. Something is going to be wrong.

Chris Lewis wrote:

According to Jeff Wisnia :

Ron Hardin wrote:

Toller wrote:


What kind of short was it that didn't trip the breaker?
If you pipes were grounded why would you get a shock off them? Your
resistance has to be thousands of times higher than the water pipes, so if
there was some wierd short that only allowed a couple amps, 99.99% of it
would go through the pipes when you touched them.


This doesn't make any sense to me. Can anyone explain it?


Plastic pipes? The current would then be through the water, not the pipe.


You'd notice a shock when you were grounded yourself, say on a basement floor,
and touched metal in contact with the water.


Generally speaking you're not going to get much current through water with that
small a cross-section. "Feelible" _maybe_.


Continuing current would discharge through the water to grounded devices in
contact with the water, running up the electric bill.


But not by much.


It reduces the heating
requirement in the same amount, though. But it needn't be a breaker-blowing
current.


The real issue is that the copper pipe may well have a full hot short, but the
person is only getting a minor tingle because his shoes/socks are moderately
good insulators, and dry concrete isn't that good a conductor either.

If he sprayed salty water on bare feet, stepped on the concrete and touched the
pipe, it may blow him through the wall.

This is a very hazardous situation. The level of jolt _may_ depend only
on how well the other end of you is connected to ground.

I remember getting a tingle from the frame of a radial arm saw I had just
bought at an auction and plugged in.

Stupid me. I tried to confirm it by touching the saw _and_ the cover attachment
screw of a nearby outlet.

_Whammo_. That hurt!

The ground wire in the RAS plug had come adrift from the third prong and
was contacting the hot wire. The whole case was full live. But it appeared
only a minor tingle because I didn't have good conductivity to the floor.
But when I touched a grounded screw... Whap!

[I learned my lesson. If in doubt, use a voltmeter. Don't use _you_.]

Frankly, guys, if I was in shoes on a concrete floor, and just touching
a pipe gave me a tingle, I'd kill the house power _immediately_ and
get everyone out of the house.

Then, I'd get out the voltmeter, and turn on the power again. Then carefully
(touching as little as possible) start measuring voltages between "supposed"
grounds to figure out what's wrong.

I'd do exactly the same thing...For sure!


And how about those laundry machines? Unless they were both unplugged
from their outlets they should have been grounded too, so something had
to be seriously wrong with the grounding of the electrical system in
that building.


Dryers aren't hooked up to the plumbing. Washers often don't have
electrical conductivity to the plumbing either (the hoses are rubber -
our code requires a bonding strap from case to pipe, but it's often omitted...)

You missed my point there. The OP said he touched *the case* of his new
washer and got bitten. That indicates that the case of the washer wasn't
at ground potential, as it should have been if it was plugged into a
properly grounded outlet, eh?

Water heaters cases don't necessarily have good electrical connectivity to the
plumbing, because the teflon tape or pipe dope _may_ interrupt the electrical
path. Plastic certainly would. Rusty metal unions might too.

Rvery electric water heater I've worked with has had a ground terminal
on it to which an electrical ground lead from the panel should be
connected. If his wasn't then it wasn't to code.


I vote for broken main grounds to both the main electrical panel and the
plumbing, probably at a point where just one conductor was doing both
jobs. That would let all the electric wiring grounds and neutrals and
the entire plumbing system were free to be driven off ground by a faulty
element in the wather heater, or some other device with a slight amount
of internal electrical leakage.


The main thing we know is that the pipe isn't grounded. It _may_ or
may _not_ be connected to the electrical system ground. If it is, the
electrical system ground isn't connected to the dirt (or whatever the
other object the OP was touching when they got the tingle).

Any decent building code requires all metal plumbing supply lines to be
conected to earth ground. That means they'll be grounded anyway even if
there's teflon tape or perhaps dielectric couplings used. (Don't get me
started on dielectric couplings and electric water heaters, I've proved
conclusively they don't do squat to prevent corrosion of the heater tank
when the piping is grounded per code. No less an authority than the
Rheem water heater Company now advises against thier use.)

Could even be that the pipes are well grounded, but the water heater
(he was leaning against it when he touched the pipe, right? ;-) is
ungrounded and is getting a bit of stray voltage because a cracked
insulator, and it was otherwise diminished by the paint coating.

Etc.

Agreed, I think we both know something's AFU with that building's
wiring, and they ought to get a *good* professional out there to put it
right.


If the heater tank was properly grounded, I'm hard pressed to believe
that the electric field strength at the piping ports would be large
enough to put enough voltage on the water in plastic pipes to be felt,
were plastic piping used.


Forget electrical field strength. You won't feel it at these frequencies
and power levels.

Puhleeze! You can have a DC electric field you know. What do you think
causes that tingling you feel when standing outdoors just before an
electrical storm hits? The charge on those clouds sure ain't AC is it?
And you can have a field in any media that isn't a perfect conductor,
such as water.

All I was saying is that the water in the tank isn't a perfect
conductor. So (if the tank was grounded per the "plastic pipe" thesis)
the majority of the leakage current from a rotted through element would
flow to the grounded metal nearest the break, because the shortest path
through the water will have the least resistance. There would be very
little current flowing through the much longer paths to the inlet and
outlet bushings, and I'd expect the voltage there would be negligable.
Of course if the tank shell *weren't grounded* then the whole tank and
the water in it would probably just follow one half of the line voltage.

Just my .02,

Jeff
--

Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"If you can smile when things are going wrong, you've thought of someone
to blame it on."

According to Jeff Wisnia :

Chris Lewis wrote:

Frankly, guys, if I was in shoes on a concrete floor, and just touching
a pipe gave me a tingle, I'd kill the house power _immediately_ and
get everyone out of the house.

Then, I'd get out the voltmeter, and turn on the power again. Then carefully
(touching as little as possible) start measuring voltages between "supposed"
grounds to figure out what's wrong.

I'd do exactly the same thing...For sure!

Good, someone agrees with my paranoia ;-)

And how about those laundry machines? Unless they were both unplugged
from their outlets they should have been grounded too, so something had
to be seriously wrong with the grounding of the electrical system in
that building.

Dryers aren't hooked up to the plumbing. Washers often don't have
electrical conductivity to the plumbing either (the hoses are rubber -
our code requires a bonding strap from case to pipe, but it's often omitted...)

You missed my point there. The OP said he touched *the case* of his new
washer and got bitten. Whoops, you're right. Sorry.

That indicates that the case of the washer wasn't
at ground potential, as it should have been if it was plugged into a
properly grounded outlet, eh?

Basically, I think we all agree that the plumbing isn't grounded properly.

I was more exploring the possibility that the plumbing wasn't grounded,
but the house electrical system is. Getting a tingle off the dryer
frame (or the washer if it's not bonded directly to the pipe) certainly
does suggest that the house ground isn't grounded properly either.

Unless he was leaning against the pipes when he touched the dryer and washer,
and he _thinks_ it was the dryer/washer at fault, when it was really the pipes.

The reason I'm casting about for alternatives is because (a) I'm uncomfortable
with the fact that _two_ failures are needed to explain the symptoms - a buggered
main system ground _and_ a ground fault energizing things and (b) if he's
going to try to diagnose this himself (which I don't really think he should),
he needs to know all the possibilities.

The one (remote) possibility that really concerns me is that he _may_ have
a loose/bad neutral between the panel and the pole.

Why? Well, that _single_ fault would imply that the neutral/ground voltage
would be pulled "away" from dirt potential simply by imbalanced current thru
the two hots. As such, he'd see a moderate tingle voltage on the ground,
anywhere, but that tingle voltage will vary wildly depending on what things
are turned on in the house.

[No, a grounding electrode will _not_ provide enough conductivity to ensure
that the grounding system stayed at dirt potential.]

The only reason I didn't jump to it immediately is that the brighten/dimming
of lights that are also symptomatic of this are usually _immediately_ obvious
and he'd have mentioned it.

Water heaters cases don't necessarily have good electrical connectivity to the
plumbing, because the teflon tape or pipe dope _may_ interrupt the electrical
path. Plastic certainly would. Rusty metal unions might too.

Rvery electric water heater I've worked with has had a ground terminal
on it to which an electrical ground lead from the panel should be
connected. If his wasn't then it wasn't to code.

Right. What I was addressing is that a heater supply ground would not
necessarily help ground the pipes.

The main thing we know is that the pipe isn't grounded. It _may_ or
may _not_ be connected to the electrical system ground. If it is, the
electrical system ground isn't connected to the dirt (or whatever the
other object the OP was touching when they got the tingle).

Any decent building code requires all metal plumbing supply lines to be
conected to earth ground.

Right.

Agreed, I think we both know something's AFU with that building's
wiring, and they ought to get a *good* professional out there to put it
right.

Right.

Forget electrical field strength. You won't feel it at these frequencies
and power levels.

Puhleeze! You can have a DC electric field you know. What do you think
causes that tingling you feel when standing outdoors just before an
electrical storm hits? The charge on those clouds sure ain't AC is it?
And you can have a field in any media that isn't a perfect conductor,
such as water.

Puhleeze! ;-) I thought it so completely absurd that you could get an
tingleable electrostatic field at 240V, I didn't even consider it,
and simply assumed you were referring to electromagnetic/induction
effects. Which are only slightly less absurd at 60Hz and house power
levels than getting a detectable tingle from a 240V DC electrostatic
potential.

Of course electrical storms can cause tingles. But they're not 240V DC
are they? ;-)

All I was saying is that the water in the tank isn't a perfect
conductor. So (if the tank was grounded per the "plastic pipe" thesis)
the majority of the leakage current from a rotted through element would
flow to the grounded metal nearest the break, because the shortest path
through the water will have the least resistance. There would be very
little current flowing through the much longer paths to the inlet and
outlet bushings, and I'd expect the voltage there would be negligable.
Of course if the tank shell *weren't grounded* then the whole tank and
the water in it would probably just follow one half of the line voltage.

It could even follow line voltage, depending on how much stray conductance
to dirt potential there was, where the break was, etc.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

Chris Lewis wrote:

snipped

It could even follow line voltage, depending on how much stray conductance
to dirt potential there was, where the break was, etc.


Whatever it is, I hope the reason we haven't heard any more from the OP
isn't because he "rode old sparky" once too often while conducting (pun
intended) his DIY plumbing activities.

Maybe it's really his damp concrete floor that's electrified and we've
all been barking up the wrong tree?

Barking....Hmm, that reminded me that we've had some bad things
happening to dogs here in Red Sox country this winter due to pavement
surface electrification caused by leakage from damaged buried power
lines. That's a subject I never knew about before things started going
whacko here.

The liability lawyers must be licking their chops, and the pet shops
have been sold out of insulating doggy boots for weeks. See:

http://www.boston.com/news/local/mas...ctrocutes_dog/

Jeff


--
Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"My luck is so bad that if I bought a cemetery, people would stop dying."

On Wed, 24 Mar 2004 13:18:29 -0500, Jeff Wisnia
wrote:

| Barking....Hmm, that reminded me that we've had some bad things
| happening to dogs here in Red Sox country this winter due to pavement
| surface electrification caused by leakage from damaged buried power
| lines. That's a subject I never knew about before things started going
| whacko here.

In Beantown you got dogs getting zapped, but here in Yankee country we
got people:


(New York-WABC, January 19, 2004) — The medical examiner has confirmed
that a woman who died while walking her dogs in the East Village
Friday night was electrocuted.

He says 30-year-old Jodie Lane stepped on an electrified metal plate
covering a Consolidated Edison utility box on 11th Street and First
Avenue.

Witnesses say the victim was electrocuted as she was trying to help
her dogs, who were barking and fighting each other in reaction to fear
and pain after they stepped on the plate.

The pets survived the electrical shock. A police officer who tried to
help Lane had to be treated after being shocked, too, but authorities
say she will be okay.

w_tom wrote:
1) All connections to water pipes must be to remove
electricity from those pipes; never to dump electricity into
those pipes. Pipes are no longer acceptable as ground - earth
or safety. Connection to earth ground must be via dedicated
earth ground connector - and not via water pipes.

You have made this assertion before and I have pointed out before that,
in any jurisdiction that has adopted the US National Electric Code,
using an underground metal water pipe that is ten or more feet long as a
grounding electrode is required. Not connecting the grounded buss bar
in the service equipment to that water pipe is a violation of the law
that adopts the US NEC by reference.
--
Tom

Connecting to a dedicated earth ground is now required.
Earthing via water pipe is no longer acceptable since water
pipes can and may be replaced by plastic. Code has changed
since water pipe was considered a good earth ground. As
posted before, earth ground should be a dedicated electrode.

NEC also still demands connection to water pipe. But that
is only to remove electricity from that water pipe; not to be
the earth ground.

Takoma Park Volunteer Fire Department Postmaster wrote:
You have made this assertion before and I have pointed out before
that, in any jurisdiction that has adopted the US National
Electric Code, using an underground metal water pipe that is ten
or more feet long as a grounding electrode is required. Not
connecting the grounded buss bar in the service equipment to that
water pipe is a violation of the law that adopts the US NEC by
reference.
--
Tom

According to Takoma Park Volunteer Fire Department Postmaster :
w_tom wrote:
1) All connections to water pipes must be to remove
electricity from those pipes; never to dump electricity into
those pipes. Pipes are no longer acceptable as ground - earth
or safety. Connection to earth ground must be via dedicated
earth ground connector - and not via water pipes.

You have made this assertion before and I have pointed out before that,
in any jurisdiction that has adopted the US National Electric Code,
using an underground metal water pipe that is ten or more feet long as a
grounding electrode is required. Not connecting the grounded buss bar
in the service equipment to that water pipe is a violation of the law
that adopts the US NEC by reference.

It's not quite that simple - you're confusing the "removal" and "dumping"
bit ("grounding electrode" versus "grounded conductor" issues).

Both you and w_tom are right, except for your "using an underground ...
is required" bit.

For w_tom's "dumping electricity into the ground" bit:

Both the NEC and the CEC now frown on the use of underground metal pipe
as your _only_ grounding electrode.

Under some circumstances, the NEC will permit you to use a "10 foot or
more" section as a grounding electrode (if you can get a grounding strap
to within 5' of where it enters the ground, for example), but it
_usually_ requires you to add a second grounding rod.

This is because supply lines are often plastic or upgraded to plastic, and
even if they aren't, this can cause ground loops in interconnected plumbing
systems, conductivity may degrade due to corrosion, etc.

In other words, even if you do have a supply line meeting the "metallic,
10' underground" bit, it isn't _necessarily_ legal (let alone required)
to use it as a grounding electrode, and you must and/or can use alternate
means (eg: UFER, ground rod, grounding plate etc) as well/instead of.

For w_tom's "remove electricity from these pipes" bit:

In all cases, the CEC and NEC does require that metallic plumbing
MUST be interconnected to the electrical system ground so that the grounding
system can get electricity "off" the plumbing.

As a logical consequence, that 10' of underground metallic pipe that you've
interconnected to the system ground may _act_ as a grounding electrode, but
it may _not_ be considered a grounding electrode for the purposes of code
compliance.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

Chris Lewis wrote:
According to Takoma Park Volunteer Fire Department Postmaster :

w_tom wrote:

1) All connections to water pipes must be to remove
electricity from those pipes; never to dump electricity into
those pipes. Pipes are no longer acceptable as ground - earth
or safety. Connection to earth ground must be via dedicated
earth ground connector - and not via water pipes.


You have made this assertion before and I have pointed out before that,
in any jurisdiction that has adopted the US National Electric Code,
using an underground metal water pipe that is ten or more feet long as a
grounding electrode is required. Not connecting the grounded buss bar
in the service equipment to that water pipe is a violation of the law
that adopts the US NEC by reference.


It's not quite that simple - you're confusing the "removal" and "dumping"
bit ("grounding electrode" versus "grounded conductor" issues).

Both you and w_tom are right, except for your "using an underground ...
is required" bit.

For w_tom's "dumping electricity into the ground" bit:

Both the NEC and the CEC now frown on the use of underground metal pipe
as your _only_ grounding electrode.

Under some circumstances, the NEC will permit you to use a "10 foot or
more" section as a grounding electrode (if you can get a grounding strap
to within 5' of where it enters the ground, for example), but it
_usually_ requires you to add a second grounding rod.

This is because supply lines are often plastic or upgraded to plastic, and
even if they aren't, this can cause ground loops in interconnected plumbing
systems, conductivity may degrade due to corrosion, etc.

In other words, even if you do have a supply line meeting the "metallic,
10' underground" bit, it isn't _necessarily_ legal (let alone required)
to use it as a grounding electrode, and you must and/or can use alternate
means (eg: UFER, ground rod, grounding plate etc) as well/instead of.

For w_tom's "remove electricity from these pipes" bit:

In all cases, the CEC and NEC does require that metallic plumbing
MUST be interconnected to the electrical system ground so that the grounding
system can get electricity "off" the plumbing.

As a logical consequence, that 10' of underground metallic pipe that you've
interconnected to the system ground may _act_ as a grounding electrode, but
it may _not_ be considered a grounding electrode for the purposes of code
compliance.

There is no gentle way to say this. Your wrong. The only reason I'm
making an issue of this is so that no unsuspecting DIYer will fail to
make the required grounding electrode conductor connection to the
underground metal water piping and thus fail inspection.
If available on the premise there are four things that must be used as
grounding electrodes. These are
A concrete encased electrode
The metal frame of the building
A ground ring
An underground metal water pipe ten or more feet long.

In houses with a complete Pex water piping system and no interior metal
piping that could possibly become energized the connection to the metal
supply lateral from the water main is required by the US NEC. In houses
that have been remodeled so that most of the interior water piping has
been replaced with plastic you must make two connections to the piping.
One to attach a grounding electrode conductor to the underground metal
water piping and the other to bond the remaining interior metallic
piping to the grounded current carrying conductor of the service. Both
connections are required by the US NEC.
--
Tom H

One can attach electric service to the 10 foot buried water
pipe as an earth ground and will still fail inspection. Why?
According to new code, that facility still does not have an
acceptable earth ground. Water company may at any time
replace that 10 foot of copper pipe with plastic. Because
this can happen, code says water pipe is not a reliable earth
ground. The code says that one of those four items (Ufer
ground, 10 foot rod, ground plate, etc) must also be installed
because THAT is the earth ground.

Again, not acceptable to dump electricity into pipes.
Connections to pipes (in some jurisdictions, that also
includes gas pipe) is to remove electricity from those pipes.
Pity the poor plumber standing in water only to discover the
pipe he has just disconnected is conducting electricity into
earth. Just another reason why pipes are connected only to
*remove* electricity - not dump electricity into them for the
purpose of earthing.

NEC requires connection to water pipes - to remove
electricity. That is the change of philosophy that also
requires a separate earth ground installed only to be the
earth ground. Without that dedicated earth ground, a facility
will not pass inspection.

If TPVFDP was correct, then that plumber standing in water
would be electrically shocked - a totally unacceptable
situation. Earth ground must be via something dedicated only
for earthing; immediately adjacent to breaker box and service
entrance.

Now the technicals from code:
250.53(D)(1) Suppliemental Electgrod Required. A metal underground water pipe shall be supplemented by an additional electrode of the type specificed in 250.52(A)(2) through (A)(7). ...

(A)(2) through (7) are Metal frame of building, concrete
encased electrode (Ufer ground), ground ring, 8 foot ground
rod, or buried plate electrode.

IOW if water pipe is used for earthing, then another
dedicated electrode must also be installed. But if that other
dedicated electrode is installed, then water pipe earthing is
not required. In short, the water pipe is not sufficient for
earthing.

Takoma Park Volunteer Fire Department Postmaster wrote:
There is no gentle way to say this. Your wrong. The only reason I'm
making an issue of this is so that no unsuspecting DIYer will fail to
make the required grounding electrode conductor connection to the
underground metal water piping and thus fail inspection.
If available on the premise there are four things that must be used as
grounding electrodes. These are
A concrete encased electrode
The metal frame of the building
A ground ring
An underground metal water pipe ten or more feet long.

In houses with a complete Pex water piping system and no interior
metal piping that could possibly become energized the connection to
the metal supply lateral from the water main is required by the US
NEC. In houses that have been remodeled so that most of the
interior water piping has been replaced with plastic you must make
two connections to the piping.
One to attach a grounding electrode conductor to the underground
metal water piping and the other to bond the remaining interior
metallic piping to the grounded current carrying conductor of the
service. Both connections are required by the US NEC.

w_tom wrote:

One can attach electric service to the 10 foot buried water pipe as
an earth ground and will still fail inspection. Why? According to
new code, that facility still does not have an acceptable earth
ground. Water company may at any time replace that 10 foot of copper
pipe with plastic. Because this can happen, code says water pipe is
not a reliable earth ground. The code says that one of those four
items (Ufer ground, 10 foot rod, ground plate, etc) must also be
installed because THAT is the earth ground.

Again, not acceptable to dump electricity into pipes. Connections to
pipes (in some jurisdictions, that also includes gas pipe) is to
remove electricity from those pipes. Pity the poor plumber standing
in water only to discover the pipe he has just disconnected is
conducting electricity into earth. Just another reason why pipes are
connected only to *remove* electricity - not dump electricity into
them for the purpose of earthing.

NEC requires connection to water pipes - to remove electricity. That
is the change of philosophy that also requires a separate earth
ground installed only to be the earth ground. Without that dedicated
earth ground, a facility will not pass inspection.

If TPVFDP was correct, then that plumber standing in water would be
electrically shocked - a totally unacceptable situation. Earth
ground must be via something dedicated only for earthing; immediately
adjacent to breaker box and service entrance.

Now the technicals from code:

250.53(D)(1) Suppliemental Electgrod Required. A metal
underground water pipe shall be supplemented by an additional
electrode of the type specificed in 250.52(A)(2) through (A)(7).
...


(A)(2) through (7) are Metal frame of building, concrete encased
electrode (Ufer ground), ground ring, 8 foot ground rod, or buried
plate electrode.

IOW if water pipe is used for earthing, then another dedicated
electrode must also be installed. But if that other dedicated
electrode is installed, then water pipe earthing is not required. In
short, the water pipe is not sufficient for earthing.

Takoma Park Volunteer Fire Department Postmaster wrote:

There is no gentle way to say this. Your wrong. The only reason
I'm making an issue of this is so that no unsuspecting DIYer will
fail to make the required grounding electrode conductor connection
to the underground metal water piping and thus fail inspection. If
available on the premise there are four things that must be used as
grounding electrodes. These are A concrete encased electrode The
metal frame of the building A ground ring An underground metal
water pipe ten or more feet long.

In houses with a complete Pex water piping system and no interior
metal piping that could possibly become energized the connection to
the metal supply lateral from the water main is required by the US
NEC. In houses that have been remodeled so that most of the
interior water piping has been replaced with plastic you must make
two connections to the piping. One to attach a grounding electrode
conductor to the underground metal water piping and the other to
bond the remaining interior metallic piping to the grounded current
carrying conductor of the service. Both connections are required
by the US NEC.

You are one obstinate fella. How much electrical work have you done?
Once again I assure you that my only reason for making an issue of this
is that someone who relies on your advice can come to harm.

250.50 Grounding Electrode System.
If available on the premises at each building or structure served,
each item in 250.52(A)(1) through (A)(6) shall be bonded together to
form the grounding electrode system. Where none of these electrodes
are available, one or more of the electrodes specified in 250.52(A)(4)
through (A)(7) shall be installed and used.
250.52 Grounding Electrodes.
(A) Electrodes Permitted for Grounding.
(1) Metal Underground Water Pipe. A metal underground water pipe in
direct contact with the earth for 3.0 m (10 ft) or more (including any
metal well casing effectively bonded to the pipe) and electrically
continuous (or made electrically continuous by bonding around insulating
joints or insulating pipe) to the points of connection of the grounding
electrode conductor and the bonding conductors. Interior metal water
piping located more than 1.52 m (5 ft) from the point of entrance to the
building shall not be used as a part of the grounding electrode system
or as a conductor to interconnect electrodes that are part of the
grounding electrode system.
(2) Metal Frame of the Building or Structure. The metal frame of the
building or structure, where effectively grounded.
(3) Concrete-Encased Electrode. An electrode encased by at least 50 mm
(2 in.) of concrete, located within and near the bottom of a concrete
foundation or footing that is in direct contact with the earth,
consisting of at least 6.0 m (20 ft) of one or more bare or zinc
galvanized or other electrically conductive coated steel reinforcing
bars or rods of not less than 13 mm (½ in.) in diameter, or consisting
of at least 6.0 m (20 ft) of bare copper conductor not smaller than 4
AWG. Reinforcing bars shall be permitted to be bonded together by the
usual steel tie wires or other effective means.
(4) Ground Ring. A ground ring encircling the building or structure, in
direct contact with the earth, consisting of at least 6.0 m (20 ft) of
bare copper conductor not smaller than 2 AWG.
(5) Rod and Pipe Electrodes. Rod and pipe electrodes shall not be less
than 2.5 m (8 ft) in length and shall consist of the following materials.
(a) Electrodes of pipe or conduit shall not be smaller than metric
designator 21 (trade size 3/4) and, where of iron or steel, shall have
the outer surface galvanized or otherwise metal-coated for corrosion
protection.
(b) Electrodes of rods of iron or steel shall be at least 15.87 mm (5/8
in.) in diameter. Stainless steel rods less than 16 mm (5/8 in.) in
diameter, nonferrous rods, or their equivalent shall be listed and shall
not be less than 13 mm (1/2 in.) in diameter.
(6) Plate Electrodes. Each plate electrode shall expose not less than
0.186 m2 (2 ft2) of surface to exterior soil. Electrodes of iron or
steel plates shall be at least 6.4 mm (1/4 in.) in thickness. Electrodes
of nonferrous metal shall be at least 1.5 mm (0.06 in.) in thickness.
(7) Other Local Metal Underground Systems or Structures. Other local
metal underground systems or structures such as piping systems and
underground tanks.

There is no way you can read NEC section 250-50 that allows you to avoid
using the underground metal water piping as part of the grounding
electrode system. That includes instances were the underground metal
service lateral is the only metallic pipe on the premises. It is true
that if the water piping is the only electrode available that it must be
supplemented by another electrode that is installed by the electrician.

It is also true that any plumber that opens a metallic service lateral
without checking for current and/or bonding around the work can get hurt
or even killed. I have attended two incidents of that kind as a
volunteer firefighter / rescuer. I have placed current transformers
around service laterals to demonstrate the danger to plumbers who were
about to begin working on them.

You have made the point repeatedly that a short connection to earth
ground is the heart and sole of surge and spike resistance for the homes
wiring system and the appliances attached to it. How many ground rod
impedance measurements have you done? I have done hundreds and I can
assure you that it is rare to find a two rod electrode system that is
under fifty ohms of impedance. I have also checked hundreds of
grounding electrode system impedances and I find that the impedance of
the water piping electrode is often ten ohms or less.
--
Tom H

According to Tom Horne :

250.50 Grounding Electrode System.
....
250.52 Grounding Electrodes.
(A) Electrodes Permitted for Grounding.
(1) Metal Underground Water Pipe.

.....

There is no way you can read NEC section 250-50 that allows you to avoid
using the underground metal water piping as part of the grounding
electrode system.

Actually, one can show that very easily: note (A) above:

"Electrodes PERMITTED for Grounding".

Emphasis added.

It doesn't say it's "REQUIRED if present" for use as a grounding conductor.

It says it _can_ be used as a grounding conductor (and elsewhere says if used
it needs to be supplemented).

Elsewhere in the code it goes on to say that such pipes MUST be grounded.

Which means in the end it doesn't matter, because it's going to _act_ as
a grounding electrode, whether the NEC thinks of it as that or not.

This whole argument is silly - it doesn't matter which way, because it's
going to be grounded (and in intimate earth contact giving decent duty
as an electrode) ANYWAY.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

"Chris Lewis" wrote in message
...
According to Tom Horne :

250.50 Grounding Electrode System.
...
250.52 Grounding Electrodes.
(A) Electrodes Permitted for Grounding.
(1) Metal Underground Water Pipe.

....

There is no way you can read NEC section 250-50 that allows you to avoid
using the underground metal water piping as part of the grounding
electrode system.

Actually, one can show that very easily: note (A) above:

"Electrodes PERMITTED for Grounding".

Emphasis added.

It doesn't say it's "REQUIRED if present" for use as a grounding
conductor.


Probably because you CONVENIENTLY didn't quote 250.50, instead replacing it
with "..."
Quoted from NEC Section 250.50 Grounding Electrode System:
"IF AVAILABLE on the premises at each building or structure served, each
item in 250.52(A)(1) through (A)(6) SHALL BE bonded together to form the
grounding electrode system. Where NONE of these electrodes are AVAILABLE,
one or more of the electrodes specified in 250.52(A)(4) through (A)(7) shall
be used and installed."

250.52(A) Grounding Electrodes.
(1) Metal Underground Water Pipe.
(2) Metal Frame of the Building or Structure.
(3) Concrete-Encased Electrode
(4) Ground Ring
(5) Rod and Pipe Electrode
(6) Plate Electrode
(7) Other Local Metal Underground Systems or Structures.

Just so you won't also misinterpret (A)(7), 250.52(B) makes it clear that
metal UNDERGROUND gas piping systems or aluminum electrodes shall not be
used as grounding electrodes.

It says it _can_ be used as a grounding conductor (and elsewhere says if
used
it needs to be supplemented).

Elsewhere in the code it goes on to say that such pipes MUST be grounded.

Which means in the end it doesn't matter, because it's going to _act_ as
a grounding electrode, whether the NEC thinks of it as that or not.


Try to learn the difference between why interior metal piping is required to
be bonded to the electric grounding system and what constitutes a grounding
electrode system. So far, you are clueless. Try this:
http://www.iaei.org/products/books_02soares.htm


This whole argument is silly - it doesn't matter which way, because it's
going to be grounded (and in intimate earth contact giving decent duty
as an electrode) ANYWAY.
--

Yes, if you don't understand electric system grounding, it's easy to see how
you would think that the argument is silly.

Chris Lewis wrote:

According to Tom Horne :


250.50 Grounding Electrode System.

...

250.52 Grounding Electrodes.
(A) Electrodes Permitted for Grounding.
(1) Metal Underground Water Pipe.


....


There is no way you can read NEC section 250-50 that allows you to avoid
using the underground metal water piping as part of the grounding
electrode system.


Actually, one can show that very easily: note (A) above:

"Electrodes PERMITTED for Grounding".

Emphasis added.

It doesn't say it's "REQUIRED if present" for use as a grounding conductor.

It says it _can_ be used as a grounding conductor (and elsewhere says if used
it needs to be supplemented).

Elsewhere in the code it goes on to say that such pipes MUST be grounded.

Which means in the end it doesn't matter, because it's going to _act_ as
a grounding electrode, whether the NEC thinks of it as that or not.

This whole argument is silly - it doesn't matter which way, because it's
going to be grounded (and in intimate earth contact giving decent duty
as an electrode) ANYWAY.

W Tom's position is that you can forgo connecting to an underground
metal water pipe if you have another electrode. Did you read the first
section of the US NEC that I quoted? It says
"250.50 Grounding Electrode System.
If available on the premises at each building or structure served,
each item in 250.52(A)(1) through (A)(6) shall be bonded together to
form the grounding electrode system. Where none of these electrodes
are available, one or more of the electrodes specified in 250.52(A)(4)
through (A)(7) shall be installed and used. "
Note the use of the prescriptive SHALL in the first sentence. If the
water pipe is there you must use it as part of the grounding electrode
system. That remains true even when there is no other metallic piping
present. Surely you are not saying that the underground metal water
pipe in a building with no interior metallic piping is "likely to become
energized" thus falling under the bonding requirement.
--
Tom

Not only did TPVFDP ignore "250.53(D)(1) Supplemental
Electrode Required." TPVFDP also failed to carefully read and
therefore totally misconstrued what was posted. Water pipe
must be bonded to remove electricity from that water pipe.
IOW safety ground system must connect to water pipe. But
water pipe alone is not sufficient for earth grounding. Even
if water pipe is used as an earth ground, still another
earthing ground must be installed.

Post the specific statement where I say, "you can forgo
connecting to an underground metal water pipe if you have
another electrode." You made that mistake of reading
selectively previously. I corrected you then. Why do you
'only read what you want to read' again?

Water pipes must be grounded to remove electricity from
those pipes. The list of acceptable earth grounds are in
250.52(A)(2) through (A)(7). They are (and to repeat again)
metal frame of building or structure, concrete-encased
electrode, ground ring, rod and pipe electrodes, plate
electrodes, other local metal underground systems or
structures. The water pipe [of 250.52(A)(1)] is no longer
sufficient for earth grounding as stated quite bluntly in
"252.53(D)(2) Supplemental Electrode Required"


Some jurisdictions (some gas companies) require a ground
connection to gas pipe just like to water pipe. Consult local
company for details. Again not bonded for earth grounding.
That connection required by some gas companies is to remove
electricity from interior gas pipe. Again the concept.
Neither water nor gas pipes are either sufficient or
acceptable as an earth ground. But connection to pipes is
(water) or may be (gas) required to remove electricity from
those pipes. List of required earth ground is 250.52(A)(2)
through (A)(7).

Takoma Park Volunteer Fire Department Postmaster wrote:
W Tom's position is that you can forgo connecting to an underground
metal water pipe if you have another electrode. Did you read the
first section of the US NEC that I quoted? It says
"250.50 Grounding Electrode System.
If available on the premises at each building or structure served,
each item in 250.52(A)(1) through (A)(6) shall be bonded together to
form the grounding electrode system. Where none of these electrodes
are available, one or more of the electrodes specified in 250.52(A)(4)
through (A)(7) shall be installed and used. "
Note the use of the prescriptive SHALL in the first sentence. If the
water pipe is there you must use it as part of the grounding electrode
system. That remains true even when there is no other metallic piping
present. Surely you are not saying that the underground metal water
pipe in a building with no interior metallic piping is "likely to
become energized" thus falling under the bonding requirement.
--
Tom

"w_tom" wrote in message ...
Water pipes must be grounded to remove electricity from
those pipes.

Perhaps we need diodes on our pipes so that current can only leave the pipes and not come into the
house on a ground fault.

--
Mark
Kent, WA

w_tom wrote:

Snip
IOW if water pipe is used for earthing, then another
dedicated electrode must also be installed. But if that other
dedicated electrode is installed, then water pipe earthing is
not required. In short, the water pipe is not sufficient for
earthing.


Did you write these words or not? You said that water pipe earthing is
not required and yet 250-50 says it is.
--
Tom H

Posted in the paragraph that discusses earthing:
IOW if water pipe is used for earthing, then another
dedicated electrode must also be installed. But if that
other dedicated electrode is installed, then water pipe
earthing is not required. In short, the water pipe is
not sufficient for earthing.

Earthing - not bonding. Two separate functions. Bonding
was defined previously in same post. Stated quite clearly
that a water pipe must connect to breaker box safety ground:
NEC requires connection to water pipes - to remove electricity.

Tom Horne selects one paragraph out of context, then draws
an erroneous conclusion. A conclusion possible only if he
ignores the entire post or does not understand the difference
between bonding and earthing functions. Water pipe alone is
not sufficient for earthing - as posted. But water pipe must
be bonded to breaker box panel for human safety - to remove
electricity from that water pipe - as posted.

Please, Tom Horne. Before wildly jumping to conclusions on
only one paragraph, first read and comprehend the entire
post. How much reading have you done? Someone who relies
on your selective reading can come to harm. g

Earthing connection is to keep breaker box safety ground and
earth ground equipotential; not to trip circuit breaker on
wire fault. Bonding causes a circuit breaker to trip should a
wiring fault occur. Earthing and bonding are two different
functions that may or may not share same wire. Somehow Tom
Horne has confused an earthing connection with a bonding
connection. Water pipe must be bonded to breaker box so that
a wiring fault will trip circuit breaker - no earthing ground
involved. Water pipe is not sufficient as a connection to
earth ground. Previous post stated same - if entire post was
first comprehended.

Tom Horne wrote:
w_tom wrote:
Snip
IOW if water pipe is used for earthing, then another
dedicated electrode must also be installed. But if that other
dedicated electrode is installed, then water pipe earthing is
not required. In short, the water pipe is not sufficient for
earthing.


Did you write these words or not? You said that water pipe
earthing is not required and yet 250-50 says it is.
--
Tom H

"w_tom" wrote in message ...
Posted in the paragraph that discusses earthing:
IOW if water pipe is used for earthing, then another
dedicated electrode must also be installed. But if that
other dedicated electrode is installed, then water pipe
earthing is not required. In short, the water pipe is
not sufficient for earthing.

Earthing - not bonding. Two separate functions. Bonding
was defined previously in same post. Stated quite clearly
that a water pipe must connect to breaker box safety ground:
NEC requires connection to water pipes - to remove electricity.


Perhaps its just semantics, but if a water pipe is in contact with the earth for 10 feet or more, it
MUST be used as a grounding electrode. Because it could be replaced by plastic in the future, NEC
mandates an additional ground in case this one gets disabled by a plumber. It should make an
excellent ground, as its usually much longer than rods. Ideally, the water pipe would be near the
main panel so you can have a short grounding electrode conductor to that pipe.

If the pipe is not in contact with the earth, then it must be bonded. Whether you're bonding or
grounding, NEC requires the same size of wire (sized per the 250.66 grounding electrode conductor
sizes) for water pipes. Normally, bonding only connections can use smaller wires per 250.122.
Whether you're grounding or bonding the water pipe, you end up doing the same thing with the same
size wire. Only difference in the ground -vs- bond case is where that wire must be attached --
within 5' of where the pipe enters the house if it is a grounding electrode.

Only thing I'd like to know from Tom Horn's impedance measurements is at what frequency they were
measured. I would expect lightning surges to be high frequency and skin effect and wire bend radius
could me much more important than they are at 60 Hz.

--
Mark
Kent, WA

Mark or Sue wrote:
"w_tom" wrote in message ...

Posted in the paragraph that discusses earthing:

IOW if water pipe is used for earthing, then another
dedicated electrode must also be installed. But if that
other dedicated electrode is installed, then water pipe
earthing is not required. In short, the water pipe is
not sufficient for earthing.

Earthing - not bonding. Two separate functions. Bonding
was defined previously in same post. Stated quite clearly
that a water pipe must connect to breaker box safety ground:

NEC requires connection to water pipes - to remove electricity.



Perhaps its just semantics, but if a water pipe is in contact with the earth for 10 feet or more, it
MUST be used as a grounding electrode. Because it could be replaced by plastic in the future, NEC
mandates an additional ground in case this one gets disabled by a plumber. It should make an
excellent ground, as its usually much longer than rods. Ideally, the water pipe would be near the
main panel so you can have a short grounding electrode conductor to that pipe.

If the pipe is not in contact with the earth, then it must be bonded. Whether you're bonding or
grounding, NEC requires the same size of wire (sized per the 250.66 grounding electrode conductor
sizes) for water pipes. Normally, bonding only connections can use smaller wires per 250.122.
Whether you're grounding or bonding the water pipe, you end up doing the same thing with the same
size wire. Only difference in the ground -vs- bond case is where that wire must be attached --
within 5' of where the pipe enters the house if it is a grounding electrode.

Only thing I'd like to know from Tom Horn's impedance measurements is at what frequency they were
measured. I would expect lightning surges to be high frequency and skin effect and wire bend radius
could me much more important than they are at 60 Hz.

--
Mark
Kent, WA


I'm using three different ground impedance testers, One four pole
biddle hand crank, one three pole biddle battery operated, and one
inductive coupled clamp on type. I always use at least two on each
site. The three pole biddle can be rigged for testing grounding
electrodes against the multi grounded neutral, against another electrode
such as the utility water main system, or against two reference rods
driven in at 100 & 150 feet. I don't recall the test frequencies of the
biddle three pole or transformer coupled units.
--
Tom H

w_tom wrote:
Posted in the paragraph that discusses earthing:

IOW if water pipe is used for earthing, then another
dedicated electrode must also be installed. But if that
other dedicated electrode is installed, then water pipe
earthing is not required. In short, the water pipe is
not sufficient for earthing.


Earthing - not bonding. Two separate functions. Bonding
was defined previously in same post. Stated quite clearly
that a water pipe must connect to breaker box safety ground:

NEC requires connection to water pipes - to remove electricity.


Tom Horne selects one paragraph out of context, then draws
an erroneous conclusion. A conclusion possible only if he
ignores the entire post or does not understand the difference
between bonding and earthing functions. Water pipe alone is
not sufficient for earthing - as posted. But water pipe must
be bonded to breaker box panel for human safety - to remove
electricity from that water pipe - as posted.

Please, Tom Horne. Before wildly jumping to conclusions on
only one paragraph, first read and comprehend the entire
post. How much reading have you done? Someone who relies
on your selective reading can come to harm. g

Earthing connection is to keep breaker box safety ground and
earth ground equipotential; not to trip circuit breaker on
wire fault. Bonding causes a circuit breaker to trip should a
wiring fault occur. Earthing and bonding are two different
functions that may or may not share same wire. Somehow Tom
Horne has confused an earthing connection with a bonding
connection. Water pipe must be bonded to breaker box so that
a wiring fault will trip circuit breaker - no earthing ground
involved. Water pipe is not sufficient as a connection to
earth ground. Previous post stated same - if entire post was
first comprehended.

Tom Horne wrote:

w_tom wrote:
Snip

IOW if water pipe is used for earthing, then another
dedicated electrode must also be installed. But if that other
dedicated electrode is installed, then water pipe earthing is
not required. In short, the water pipe is not sufficient for
earthing.


Did you write these words or not? You said that water pipe
earthing is not required and yet 250-50 says it is.
--
Tom H

Are you saying that you did not mean that "water pipe earthing is not
required." If that is true then we have no disagreement. My concern
was and continues to be that an ordinary DIYer might read your post and
take that meaning. As long as we agree that in areas that have adopted
the US NEC you must attach a conductor to an underground metal water
pipe that is sized in accordance with 250.66, is free of reversible
splices or joints, is connected within five feet of were the piping
enters the structure, and terminates on the service equipment enclosures
bonded buss bar than I don't care what we each believe the purpose is.
I just want to avoid this thread misleading someone into making a
dangerous mistake.

I would like to ask you to think about a question. In a house that has
an underground metal pipe that; serves only a yard bib used for
gardening, the underground piping is forty feet long, and it changes
over to CPVC (plastic) piping just inside the basement wall; do you
connect any conductor to that piping? The house has no other metallic
piping and I mean none. If you do connect a conductor to that piping
what is the purpose of that conductor?
--
Tom H

The code says water pipe 'earthing' may be performed but
that water pipe 'earthing' is not sufficient. That earthing
being different from the still required 'bonding a water pipe
to breaker box' so as to remove electricity from the pipe.
Function that removes electricity - bonding - is required even
though water pipe (alone) is no longer sufficient for earthing
function.

Due to installation of plastic pipe (during repair), some
jurisdictions now require a dedicated ground wire (ie. 6 AWG)
to pipes that connect to steel bathtubs. Concept is that an
electrical wire anywhere inside walls could fault to tub or
pipes (water or drain). Tub or pipe having been electrically
isolated because plumber made his repair; creating a potential
electrical hazard.

Concept that applies here and to rest of discusson: plumber
is not expected to install protection from a hazardous
electrical problem. Electric should be installed so that
plumber cannot create a hazard. My opinion is that this
dedicated tub safety ground should be required for all metal
bathtubs regardless of whether plastic does or does not
currently exist; because potential danger (created by
existence of CPVC in Home Depot, et al) is significant.

Even when city water enters an 'all CPVC pipe' house,
inspector still wants that less than '10 foot of copper pipe
from city water' to be bonded to breaker box. An electrical
fault to that few feet of exposed, interior copper pipe is
still considered hazardous. An electrical fault might even
occur underground and outside the building. Therefore short
copper pipe still must be bonded to electrical box.

Using that principle, a metal pipe buried 40 feet to remote
outside bib also should be bonded. I can appreciate why both
that city water pipe and '40 foot pipe to bib' should be
bonded if someone inside building could touch a potentially
electrically hot pipe. But my guess is that 40 foot pipe is a
classic case of local code interpretation.


Strongly believe that all metal bathtubs even in a house
that is not CPVC should be bonded to breaker box. Like the
idea that incoming city water should still be bonded even if
house is all CPVC - for human safety. Not sure if 40 foot
outside pipe is required, by code, to be bonded to breaker
box. But do appreciate why an inspector would also want pipe
bonded. Electrical faults do happen in earth and outside of
building. Such faults to a '40 foot pipe to bib' in a
backyard would be less likely to harm humans as compared to
electrical fault out beneath the street.

To again make original point clear because 1) it is
necessary for human safety (even if rest of house is CPVC)
and 2) it is so often missing in maybe two out of ten older
homes. That breaker box connection to water pipe 'less than
five foot from entering building' is still required. Pipe
must be bonded to breaker box so as to remove electricity
from pipe; so as to cause circuit breaker to trip.

Tom Horne wrote:
Are you saying that you did not mean that "water pipe earthing is
not required." If that is true then we have no disagreement. My
concern was and continues to be that an ordinary DIYer might read
your post and take that meaning. As long as we agree that in
areas that have adopted the US NEC you must attach a conductor to
an underground metal water pipe that is sized in accordance with
250.66, is free of reversible splices or joints, is connected
within five feet of were the piping enters the structure, and
terminates on the service equipment enclosures bonded buss bar
than I don't care what we each believe the purpose is. I just want
to avoid this thread misleading someone into making a dangerous
mistake.

I would like to ask you to think about a question. In a house
that has an underground metal pipe that; serves only a yard bib
used for gardening, the underground piping is forty feet long,
and it changes over to CPVC (plastic) piping just inside the
basement wall; do you connect any conductor to that piping? The
house has no other metallic piping and I mean none. If you do
connect a conductor to that piping what is the purpose of that
conductor?
--
Tom H

According to Takoma Park Volunteer Fire Department Postmaster :
Chris Lewis wrote:
Actually, one can show that very easily: note (A) above:

"Electrodes PERMITTED for Grounding".

W Tom's position is that you can forgo connecting to an underground
metal water pipe if you have another electrode. Did you read the first
section of the US NEC that I quoted?

You're quite right. Oops. Reading too fast.

I certainly don't subscribe to the "you don't have to connect underground
metal water pipe" to the grounding system (as electrode _or_ as bonding)
theory.

I was merely trying to point out, (as commented on by others), that in the
end result, it doesn't matter, because it _has_ to be bonded/equivalently
anyway. As do all other significant metallic building structure - ie:
ducting, metal framing.

Yes, there may be quibbles about "boundary issues", such as metal piping
ending right at the building envelope. But that would happen anyway,
such as unconnected-to-the-building water mains going beside the building.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.