I am doing a Renovation in the basement. Where the Copper water pipe goes
down vertically into the ground, the concrete floor is missing. there is a
7" trapezoidal gap in the pour. I have partially covered it with the 2x4"
flat to the floor that is part of a new stud wall. but the hole still juts
out. The hole sticks into what is to be a finished tiled floor I will do
shortly diagonally 1.5" x 3". Then on the other side of a 2x2" partition
wall the hole continues about another 6"x6". There is also the main ground
wire from the fuse box screwed to the same copper water pipe about an inch
above concrete level. However the bare wire low gauge crimp clip which
attaches the wire to the pipe with a wrap around steel clamp and bolt is
kinked right off, and I have mashed the bare twisted wire just into the main
water shut off tap wheel. It is all right at the water meter.
1) Can I fill this hole with concrete (or how much of the hole). It is
quite a noticeable gap, with nothing but dirt a few inches down. A little
of this hole is on the edge of a new tile floor I'll be doing. I'd like to
fill it (all) in. Is there any reason not to wrap an 1/16"- 1/8" flexible
whatever around the water pipe, and fill it up.
2) What if any danger am I in handling the bare ground wire for a while
to re-crimp/clamp without shutting off the main power?
We're doing a major addition to our house which required an upgrade to our
water service. After they broke out the floor, pulled the old stuff out,
and put the new in, they filled the hole with concrete right up to the pipe.
My little suburb here is pretty strict with the codes, so I'm sure that's
Close to zero. If you're concerned about that, I'd stay out of the shower
if I were you.
In most cases, contact with the ground wire is harmless. However, you
can get shocked by it due to static electricity or unusual circumstances
such as an idiot doing wiring in your house, or lightning hitting the
right place. It's metal, therefore it conducts current. It has the
potential to be dangerous.
Copper and concrete are not a good mix. Many of the Levittown homes in
the NE have had to change from the original copper slab heat to
baseboard because of this.
"As time went by, some of the copper tubing began to leak, and water
would soak into the ground rather than rise up through the floor.
Consequently, homeowners didn't know when a minor leak occurred, which
eventually led to major problems. Both Levitt's and Wright's homes had
early copper piping that pushed the envelope right to its limits in
this way. If workmen operating on a tight schedule installed the piping
with too much play, the pipes could easily break. In fact, the very
nature of copper's interaction with concrete made corrosion of the
pipes likely to happen eventually, unless a protective barrier was
installed-a process that was perfected much later. Once leaks began
they were nearly impossible to fix, leading many homeowners with this
problem to abandon the systems and install baseboard convectors
You could always trust the guys at copper.org or the thousands of
people that had their system fail. I would at least wrap the pipe in a
thin layer of foam to keep the concrete from touching the copper.
Copper corrosion under slabs is a big problem all across the country.
As a consulting engineer I made many investigations of these problems.
My experience led to three basic actions to avert problems.
Don't use copper water pipe as an electrical ground. The transient
currents can turn the pipe to Swiss cheese.
If the water supply tests for any level of hardness and CO2 [Carbon
Dioxide], the stray currents will cause an electrolytic erosion of the
copper, forming Copper Carbonate inside the pipe. This is easily
identified by the Turquoise color of the deposit.
Don't install copper pipe in soil that has been treated with salt or
Copper Sulfate to inhibit weed growth. This is a common practice among
subdivision developers, causing widespread leakage in new subdivisions.
I won't even mention the lawsuits that these problems have generated.
It is something that every prospective home buyer should check out.
>Don't use copper water pipe as an electrical ground. The transient
>currents can turn the pipe to Swiss cheese.
About fifteen years ago I replaced the house ground and installed a deep
copper grounding rod into the ground water level at my mom's house. I
ran a heavy gage wire to the panel, and disconnected the ground from the
water pipe. This produced a superior ground, and probably saved the
pipes, which were experiencing corrosion from electrolosis.
A few months ago, as my sisters were preparing the house for sale (mom
passed on last year), they hired an electrician to do some work on the
house. What do you think he did? Yup! He removed the earth ground (that
was installed according to code, btw) and placed another ground back on
the water pipe. Having tested the ground every year, there wasn't any
problem with it, so who knows...
You should have made him put it back!
>> Bugs wrote
>>> >Don't use copper water pipe as an electrical ground. The transient
>>> >currents can turn the pipe to Swiss cheese.
>> About fifteen years ago I replaced the house ground and installed a
>> copper grounding rod into the ground water level at my mom's house.
>> a heavy gage wire to the panel, and disconnected the ground from the
>> pipe. This produced a superior ground, and probably saved the pipes,
>> were experiencing corrosion from electrolosis.
>> A few months ago, as my sisters were preparing the house for sale (mom
>> passed on last year), they hired an electrician to do some work on the
>> house. What do you think he did? Yup! He removed the earth ground (that
>> was installed according to code, btw) and placed another ground back on
>> the water pipe. Having tested the ground every year, there wasn't any
>> problem with it, so who knows...
Couldn't do that. My sisters are taking care of things because they live
close to there, and I also don't want to piss them off :)
There are two issues:
Is it possible that lethal voltages might be found between the copper
pipe and the grounding wire (when disconnected from the pipe, of
course)? Absolutely! It is not likely, but it can and has happened.
Second issue is what to do about it? You can carefully measure the
voltage when the wire is disconnected, but you need the right kind of
meter for that. Best, and easiest, approach is to clip a jumper between
the grounding wire and the copper pipe before removing the clamp, etc.
When you're finished, remove the jumper.
Needless to say, potentially lethal voltages are a sign of a problem
that ought to be diagnosed and corrected. They are not a normal
condition. This is very definitely not in the same class as taking a shower!
Maybe I read too fast. To "handle" the ground wire while it is connected
to ground will not be a problem. My previous post assumed you wanted to
disconnect the ground wire from the copper pipe to replace the clamp. If
so, it would be good to switch the main breaker off as well.
As a plumber, I have run into about 4 cases of the water bond having
enough voltage to give me a good tingle when it was disconnected. We
have learned to use automotive jumper cables to jumper ground wire to
water service while bond clamp is being reconnected.
Steve A wrote:
>As a plumber, I have run into about 4 cases of the water bond having
>enough voltage to give me a good tingle when it was disconnected. We
>have learned to use automotive jumper cables to jumper ground wire to
>water service while bond clamp is being reconnected.
Without going into great detail:
You have to remember that wire - ALL wire - has resistance. So when you
disconnect one, then current will take the path of least resistance to
ground. If that happens to be through you... Anywhere you are in the
circuit may just be a shorter path. More complications follow;
Your house ground is connected in your panel to the big block where the
return, or neutral, wire is connected. This wire is a current carrier,
and if you disconnect house ground, you are creating a *floating ground*
in your whole house system. This makes the "ground" a part of the live
current-carrying circuit, even if there are no direct problems with the
circuit otherwise. This is a *potentially* very dangerous condition,
especially because you don't yet know if there *is* any other problem.
The potential for disaster in this case is probably fairly low in *most*
houses, but in others, well, how do you know? Why play russian roulette?
I would highly recommend turning the main breaker off while working to
reconnect the ground. Being careful doesn't take any more time or effort
than being stupid, but you'll get bitten less.
When working on the electrical system of the house there can be problems
due to faulty wiring, poor design (and you would be pretty surprised to
find how many houses are wired really poorly), and grounds having
resistance due to corrosion, dirt, etc. Also, due to electrical wiring
having resistance, and more resistance over distance, you may find even
*de-energized* circuits carrying current through you if you aren't
careful (this is *usually* an example of poor design - not separating
multiple circuits adequately - sharing neutrals/grounds, etc. and is
very, very common in house wiring. Remember, I didn't say it was right,
I said it was common).
A case in point; I was recently working in a house replacing some
switches and outlets. In one switch box, after de-energizing the
appropriate breaker, I was pulling the white (neutral) wire out and my
hand brushed up against the grounded wall box. I received a small, but
quite noticeable electrical shock that made me run down to the basement
to verify the right breaker was turned off and again check the circuit
in the switch box with a meter. And sure enough, there was still a
significant voltage present between the hot and neutral. In this case
the circuit had the neutral tied into (shared) another circuit down the
line, and that circuit had a light on - i.e.: the circuit was carrying
current through the neutral. Due to resistance over distance (i.e.:
resistance increases over distance in the wire), the distance between
the open neutral I held - through me - to the grounded box, was shorter.
This was of course something that we repaired. Since that time I double
check every circuit I work on with a meter, and always look for
inappropriate tie-ins in every box I open. BTW, while doing that, you
would be surprised to find how many wire nuts aren't screwed on, and how
many wires are just barely hanging on - a potential fire hazard.
Since this has turned into an electrical thread I'll add this:
House I bought last year has the phone, cable, fuse box, etc 'grounded'
to the incoming cold water pipe. Two problems with this:
1 No jumper wire going around the meter (minor)
2 The water supply line coming through the foundation is plastic! (OK
probably not *plastic* but it is not metal)
I used to do on site audio recordings. As the engineer, it was my job to
make sure that all equipment was properly grounded. Audio gear that is not
grounded properly develops a very loud hum (60 cycle and more) that drowns
out anything that you try to record.
At least one half of the locations we recorded at did not have properly
grounded plugs. I carried waterpipes in the van and drove them into the
ground to get a good ground. I would connect the ground to the equipment. I
also poured water on the pipes.
This, of course, got people interested. Who is this crazy guy pounding
pipes into the ground? I almost got arrested a couple of times because the
security guys thought I was making up this wild grounding theory. They had
never heard of it.
I ended up carring around a reference book to point out the theory/science
behind grounding. I also pointed out that their electrical was not up to
code. And I could call it in. That usually shut them up.
I don't understand your last sentence. I'm saying that if you're gravely
concerned about having a "potentially lethal" voltage connected to your
plumbing pipe, then I'd avoid touching any of the plumbing in the house and
I certainly wouldn't get soaking wet and stand in a shower lest the voltage
decide I'm a better path to ground. Is there a non-zero risk of dying from
doing this? Yes, there is. So while we're at it, why don't we have the OP
wear linesman's gloves and use a hot stick to install the clamp?
From the way you've posed the question, I can't tell whether you
understand the basic electrical concepts involved.
Let me just say that appliance ground faults are so common that a good
part of the National Electrical Code (NEC) is devoted to protecting
people from them. Breaking the ground connection exposes one to the very
dangers that the ground connection was installed to protect against.
Taking a shower is just not equivalent to removing the protection
against appliance ground faults that the NEC requires.
There is no electrical safety risk in taking a shower UNLESS there has
been a grossly egregious wiring situation that would at a minimum
violate the NEC and could be grounds for criminal negligence. I would
not (and have not) advise everyone to call in an electrician before
taking a shower. But I will advise everyone who wants to break his
ground connection to be careful.
I agree with the notion that no part of our existence is without some
risk. Rationality therefore means we expend efforts to avoid a risk
commensurate with the risk's probability. I think advising the OP to be
damned careful when removing the protection required by the NEC because
without that protection you might die goes well beyond the simple truism
that nothing is without risk.
Does that clarify my statement?
You'll have to bear with me. I'm just a stupid mechanical engineer.
So what you're saying is that there could be an existing ground fault that
is currently being sent to ground through the water pipe? I take that to
mean that the ground, and thus the copper pipe it's bonded to, is energized.
I'm not sure if you're referring to removing the protection permanently or
long enough to put a proper clamp back on. I assumed the OP was talking
about removing the ground connection just long enough to get it attached
back to the pipe with a clamp. My assertion was that if there was enough
voltage present in the ground wire to kill you, that you probably had other
worries in addition. If that was the case, I wouldn't handle anything
connected to the plumbing fixtures until the situation was corrected.
Perhaps I'm wrong. Most of my work-related electrical experience was in a
slightly higher range of 15-500kV when I designed insulators for
distribution, sub-transmission, and transmission lines where the electrical
problems encountered were somewhat different.
By the way, for the OP, one thing I haven't seen mentioned is that, at least
around here, the ground is connected to the water line on just this side of
the meter. Then, another ground wire bridges the meter so that the ground
would still be in place in case the meter was removed.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.