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Discussion Starter · #1 · (Edited)
I do some drywall work on the side and this weekend I was covering up a wall that had the water main and gec.

First simple question, I probably know the answer already...

is it ok to cover up a water pipe with the gec attached? Might save me the trouble of making a hatch door.

and now the hard question:

I had a meter in my tool box and I clamped the gec and the water pipe and was getting about .5 of an amp. I never actually seen current on the gec like this?

Of course I immediately asked to turn off the main and test again and it went down to about .2 to .3 mA with power off to the building. So I assume that portion is because its a shared metal undground pipe in parallel with the poco tx.

Got me to thinking the phone and cable are connected to the gec as well and I clamped the coax on the cable co. side and noticed a small amount (around .2mA again) creeping back up to the pole as well!

When I had the HO put on various loads in the house the current on the gec was fluctuating a in the less than 1.5 A range. The Amp and 1/2 was recorded when the microwave/range hood was running and once off dropped back to about .5mA. That's the one that startled me enough to post here.

I didn't have the chance to open the panel and test but did see a balanced voltage on both legs via the dryer outlet next to me.

There was 0 current on the ground rod outside.

I asked one guy at work today and he was adamant that there should NOT be any (as in 0) current on the gec while another gentlemen was adamant in the opposite that some current is indeed normal. Neither of the arguments were very convincing.

So what do you think? Is it worth investigating further or can I get back to hanging the crappy drywall in that basement?
 

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Discussion Starter · #3 ·
You should have left access to the grounding electrode conductor clamp.

There will almost be some current on a plumbing pipe.
Trap door it is then.

However, these current readings are on the pipe and the GEC as well which is actually run in emt for protection.... so clamping the emt, clamping the exposed gec and the water pipe itself are rendering these readings.
 

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Electron Pathway Engineer
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Not sure about the NEC, but the CEC states that all electrical connections must be accessible. What does your code book say?
 

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Trap door it is then.

However, these current readings are on the pipe and the GEC as well which is actually run in emt for protection.... so clamping the emt, clamping the exposed gec and the water pipe itself are rendering these readings.
If it is on the plumbing then it will be on the grounding electrode conductor etc and vice versa
 

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animal lover /rat bastard
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Not sure about the NEC, but the CEC states that all electrical connections must be accessible. What does your code book say?

250.68 Grounding Electrode Conductor and Bonding
Jumper Connection to Grounding Electrodes.
The connection
of a grounding electrode conductor at the service, at
each building or structure where supplied by a feeder(s) or
branch circuit(s), or at a separately derived system and associated
bonding jumper(s) shall be made as specified
250.68(A) through (C).
(A) Accessibility. All mechanical elements used to terminate
a grounding electrode conductor or bonding jumper to
a grounding electrode shall be accessible.

Exception No. 1: An encased or buried connection to a
concrete-encased, driven, or buried grounding electrode
shall not be required to be accessible.


Exception No. 2: Exothermic or irreversible compression
connections used at terminations, together with the mechanical
means used to attach such terminations to fireproofed
structural metal whether or not the mechanical
means is reversible, shall not be required to be accessible.
 

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I do some drywall work on the side and this weekend I was covering up a wall that had the water main and gec.

First simple question, I probably know the answer already...

is it ok to cover up a water pipe with the gec attached? Might save me the trouble of making a hatch door.

and now the hard question:

I had a meter in my tool box and I clamped the gec and the water pipe and was getting about .5 of an amp. I never actually seen current on the gec like this?

Of course I immediately asked to turn off the main and test again and it went down to about .2 to .3 mA with power off to the building. So I assume that portion is because its a shared metal undground pipe in parallel with the poco tx.

Got me to thinking the phone and cable are connected to the gec as well and I clamped the coax on the cable co. side and noticed a small amount (around .2mA again) creeping back up to the pole as well!

When I had the HO put on various loads in the house the current on the gec was fluctuating a in the less than 1.5 A range. The Amp and 1/2 was recorded when the microwave/range hood was running and once off dropped back to about .5mA. That's the one that startled me enough to post here.

I didn't have the chance to open the panel and test but did see a balanced voltage on both legs via the dryer outlet next to me.

There was 0 current on the ground rod outside.

I asked one guy at work today and he was adamant that there should NOT be any (as in 0) current on the gec while another gentlemen was adamant in the opposite that some current is indeed normal. Neither of the arguments were very convincing.

So what do you think? Is it worth investigating further or can I get back to hanging the crappy drywall in that basement?
Mention all of this to a qualified electrician on the job and just hang drywall.
 

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Just encase the h20 clamp in 'crete :jester:

oh and, make sure it's rated for it!


~CS~
 

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Discussion Starter · #10 ·
Mention all of this to a qualified electrician on the job and just hang drywall.
Well thx for the assumption buddy..... Im a union electrician , local 1392. I do drywall in my spare time.

Any comments on the readings I rendered on the GEC?
 

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Discussion Starter · #14 · (Edited)
Question remains since I already know a little of this is normal but I am unclear to what extent.

1.5A under load on GEC. .5 not under load and with main off.


.5 leaking back on the coax with main on, bit more under load. No current on ground rod.

Normal in a city metallic water system I assume but the fluctuating voltage under load and the current on the coax is what startled me enough to ask.
....

So to what extent is this normal or not? Cant get a straight answer here nor at work.

p.s.- GEC will be accessible with the new drywall, got a nice access door like the plumbers use (god forbid I say I do plumbing work on the side!!)
 

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Question remains since I already know a little of this is normal but I am unclear to what extent.

1.5A under load on GEC. .5 not under load and with main off.


.5 leaking back on the coax with main on, bit more under load. No current on ground rod.

Normal in a municipal water system I assume but the fluctuating voltage under load and the current on the coax is what startled me enough to ask.
....

So to what extent is this normal or not? Cant get a straight answer here nor at work.

p.s.- GEC will be accessible with the new drywall, got a nice access door like the plumbers use (god forbid I say I do plumbing work on the side!!)
It's pretty common reading some current on water pipes. The current with the main off is probably coming from a neighboring service on the same transformer
 

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animal lover /rat bastard
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^what he said
 

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Discussion Starter · #17 ·
^what he said



What was also unique about this setup (at least from my experience) was that the GEC was run at least 100' from panel to the otherside of the house where the water enters. A very long run, encased in conduit, probably longer than the service drop in fact.
 

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animal lover /rat bastard
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What was also unique about this setup (at least from my experience) was that the GEC was run at least 100' from panel to the otherside of the house where the water enters. A very long run, encased in conduit, probably longer than the service drop in fact.
250.68
(C) Metallic Water Pipe and Structural Metal. Grounding
electrode conductors and bonding jumpers shall be permitted
to be connected at the following locations and used
to extend the connection to an electrode(s):
(1) Interior metal water piping located not more than 1.52 m
(5 ft) from the point of entrance to the building shall be
permitted to be used as a conductor to interconnect electrodes
that are part of the grounding electrode system.
 

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Discussion Starter · #19 ·
250.68
(C) Metallic Water Pipe and Structural Metal. Grounding
electrode conductors and bonding jumpers shall be permitted
to be connected at the following locations and used
to extend the connection to an electrode(s):
(1) Interior metal water piping located not more than 1.52 m
(5 ft) from the point of entrance to the building shall be
permitted to be used as a conductor to interconnect electrodes
that are part of the grounding electrode system.
Yea and? I have that much covered... the drywall sidework hasn't rotted my brain that much.

Theres no choice in the matter I know.
 

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Mention all of this to a qualified electrician on the job and just hang drywall
Well thx for the assumption buddy..... Im a union electrician , local 1392. I do drywall in my spare time.
?
Oh boy RIVETER, I think you are on to something :laughing:


Generally I provide access with a 2g 4s mudring.


Your amprage reading is because your path to earth is better than the POCO's
 
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