That is exactaly the point I was trying to make to John without much
He failed to comment on the OSHA reports that I quoted saying that
there had been electrocutions cased by using water pipes for system
You dont HAVE to leave the water pipes to float. If you are concerned
about water pipes floating, then connect them to one of the two ground
rods that you have put in the earth. Just DON'T use the water pipes in
any way as a system ground. Using the water pipe as a system ground
does NOT ground the water pipe. I assume you are considering
connecting a ground wire from the panel neutral bar to the water
You give Bob a hard time about getting off topic....our discussion had
nothing to do with grounding water pipes...we were talking about using
water pipes as a SYSTEM GROUND.
Does the NEC recomment grounding water pipes..and if so, how do they
recommend doing it.
J. Clarke wrote:
Last time I checked (my code book is 10 years old and it's at work rat
now) the NEC *requires* you to use the water service as a ground
electrode, then they require one additional ground electrode. (I'm not
sure if the 25 ohm rule applies to that second electrode.) The
Grounding Electrode Conductor has to be connected to the metal water
pipe within 5 feet of the meter, and then jumpered around the meter (so
the electrical path is not broken when the meter is removed.) The metal
water pipe from the street is an excellent ground, and connecting the
GEC this way also grounds the water pipes in the house (assuming
unbroken metal pipes) The GEC is not allowed to have any breaks or
splices unless they are welded or use special nonremovable connectors
that are approved for this purpose.
What I was talking about, and I /thought/ we were all talking about, was
using the nearest available cold water pipe to ground an outlet or
fixture. That was acceptable practice in the days when all water pipe
was either copper or galvanized. Even then it was not a good practice
(they probably didn't realize it at the time) because it put plumbers in
Hope this helps,
Water pipes are bonded to breaker box per NEC article 250.52(A)1 as
others have noted previously. Water pipes only grounded to earth may
not trip the circuit breaker of a faulted 'hot' wire. Bonding water
pipe directly to breaker box safety ground would protect humans in a
bathtub and working as a plumber because circuit breaker would trip
Volts500 also summarized the various household bondings in "Grounding
Rod Info" on 12 July 2003 at:
You are using the term 'using water pipes for system grounds' without
first defining two different meanings of that expression. Posted here
will be two different definitions of that same phrase.
One does not use water pipes for a system ground because electricity
should never be 'dumped' into water pipes. There must be no
intentional connection to water pipes to ground something else via
water pipes - also called 'system grounding'. "using water pipes for
system grounds" must never exist.
Meanwhile, another single connection is definitely required - a
safety ground (bonding) must connect where water pipe enters a
building. This for so many reasons and all to 'remove' electricity
from pipes and only from those pipes.
Notice two different types of ground connections; two different
reasons to bond. One that 'dumps' electricity from, for example, an
appliance is not acceptable. A second that would 'remove' electricity
only from plumbing (to even cause circuit breaker tripping) is required
by code, essential to human safety, and would even protect the
Floating pipes, when energized due to a fault, may never trip a
circuit breaker. Such fault would lurk until a worst condition occurs
- for example, human in a bath or a plumber working on pipes. Code
requires a connection from pipes to the breaker box for safety - so
that those pipes do not remained energized even when a plumber works on
them. Pipes that remain floating can remain 'hot'; a most dangerous
condition for the plumber and all other human occupants. This bonding
is completely different from "using water pipes for system grounds" -
the other type of grounding.
Bonding pipes is only to ground those pipes in cause of fault only
to those pipes; must never be for grounding anything else - never be
part of a 'system ground'. That OSHA report would be warning of
grounding something else to electrical pipes - system grounding -
completely unacceptable. But again, defined are two different types of
grounding to pipe. One type ground is not permitted and would
endanager a plumber. Other type ground is to bond only plumbing.
Other type is considered so necessary for human safety that some
jurisdictions may even require a dedicated ground wire from breaker box
to steel bathtubs. Again to 'remove' electicity only from pipes and to
not 'dump' electricity into pipes.
Two types of grounds to pipes are 1) required by code to remove
electricity only from pipes AND 2) must not use pipes to ground
anything else. That OSHA report would demonstrate why above type 2)
ground is unacceptable. Type 2) ground would be 'using water pipes for
'system ground'. Completely different from type 1) which, if not
installed, may not trip a circuit breaker trip and may then leave pipes
'hot' - a threat to human life. Type 1) grounding of pipes are
required by code. Type 2) grounding is a code violation; but moreso,
obviously unacceptable as would even be demonstrated by the OSHA report
Any ground connection to pipes that would 'dump' electricity in those
pipes (type 2) is a major threat even to plumbers. Not acceptable and
not same as other required and essential safety ground wire from pipe
to breaker box.
The NEC has REQUIRED for years that a metal water service with least 10
feet of metal in contact with the earth be used as a system grounding
electrode. Municipal metal water systems have very low ground
resistances, far lower than other readily available electrodes in a home.
As Bob said, this connection is required to be within 5 feet of the
building entrance with the meter jumpered. That makes it difficult for
even a plumber to create an electrocution hazard.
The OSHA report is not clear what the specific hazard is. Could be
connection remote from the water entrance. Also systems are required to
have a supplemental grounding electrode because water service pipes may
be replaced with plastic in the future, one of the hazards in the OSHA
You can't bond a metal water piping system without it becoming a
grounding electrode unless an insulating link is intentionally inserted
in the pipe.
"'Remove' electricity from pipes" has no meaning. It would help if you
used understandable language.
We are not talking about 1950, we are talking about a quote by an
electrician for wiring to be installed _today_.
No, you don't understand. The electrician proposed three grounding
electrodes, two of them driven into the ground and the third a water pipe.
That is what is under discussion, not some hosed up substandard job done to
a 50 year old code.
If it was wired this year it did.
So what? The OP didn't say anything about having a time machine.
We aren't talking about wiring in my house or your house, we are talking
about new wiring to be installed in someone else's house.
Which has zip all to do with the original question.
The water pipe is supposed to be grounded; the electrician will run a #6
wire all the way to a convenient place withing a few feet of the meter,
then put a jumper around the meter if there's not one already (so the
circuit is not broken if the water meter is removed.
He's using 2 ground rods tied together because that way he don't have to
check that the impedance is less than 25 ohms. (I'm not sure that's
necessary when you have the copper water service as the main grounding
I have no idea if $1600 is a good price or not, but what he's proposing
sounds reasonable. I might check about a 125A service because it would
probably cost exactly the same. Price goes up at 150A, and way up at
200A, because of the size of the wires and the conduit for the service
I did the same upgrade you're doing to my old house about 13 years ago.
(I did it myself) I put in a 150A service instead of a 100A because I
knew I wanted to add a workshop later, including a welder.
If the old wiring is in good shape I wouldn't tear it out. Install GFCI
outlets where needed, run separate ground wires to a few strategic
outlets (you don't have to tear the walls out to run a ground wire, it's
just a real PITA getting the wire thru the wall to the box)
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