bonding copper water pipe

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mjmike said:
Checked my own house this past weekend and sure enough, the copper lines were not bonded, couldn't believe it. My house is not very old either; suprized this wasen't cought (I'm not the original owner). Before bonding, I checked for mV AC at my electric water tank copper lines. I checked it to a receptacle in the area ground. There was about 220mV on it. I turned off the water heater and that levle went down some. Proceeded to bond across the hot and cold at the water tank and across the in/out of my water softener. My GEC was #4 based on the diameter with a dial indicator so i took the bond from my water line by my panel to the GEC with a split bolt. Worked out quite well. I then checked continuity at my water heater to the same receptace and got good continuity. I then checked mV again and it was about 8mV AC. I guee my only concern now is why was there mV on my water line and now that I grounded it, will I get problem with pinhole leaks in my copper lines because the voltage is flowing per say, not just present as before?
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Could have (likely was) just capacitive coupling creating this voltage. You will have more problems with degrading of the line from DC current and electrolysis than you will have from AC current.
 
mjmike said:
I guee my only concern now is why was there mV on my water line and now that I grounded it, will I get problem with pinhole leaks in my copper lines because the voltage is flowing per say, not just present as before?
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That may be the least of your problems. The water pipes were not grounded in my house when I moved in. I took care of it in the first year after taking up residence fifteen years ago.

You should see how much hair I have lost and how much weight I have gained since then.
 
kwired said:
Could have (likely was) just capacitive coupling creating this voltage. You will have more problems with degrading of the line from DC current and electrolysis than you will have from AC current.
Click to expand...

I agree with this. Even with the DMM leads in free air, they will read between 50 and 100mV AC. As for DC, I checked across the hot and cold at the water heater before bonding and no DC voltage. However, where is the DC referenced to is the question. Or is it the DC portion of an AC circuit (yes, even an AC has a little DC voltage)
 
mjmike said:
I agree with this. Even with the DMM leads in free air, they will read between 50 and 100mV AC. As for DC, I checked across the hot and cold at the water heater before bonding and no DC voltage. However, where is the DC referenced to is the question. Or is it the DC portion of an AC circuit (yes, even an AC has a little DC voltage)
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AC service alone, probably not much for DC current sources, sure there could be some DC component in the AC service.

Most DC problems come from either telephone lines, or other separately derived DC systems. You need to find those sources and find out if your water piping has become a part of a path for those systems.
 
Smart $ said:
Counterpoint is the depiction does not exemplify that. The service conductors could be 1/0 CU or 3/0 AL, or smaller.
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250.66 Size of Alternating-Current Grounding Electrode
Conductor.
(A) Connections to Rod, Pipe, or Plate Electrodes.
Where the grounding electrode conductor is connected to rod, pipe, or plate electrodes as permitted in 250.52(A)(5)
or (A)(7), that portion of the conductor that is the sole connection to the grounding electrode shall not be required to be larger than 6 AWG copper wire or 4 AWG aluminum wire.

250.66 Note: Aluminum cannot be connected to an 8? ground rod.
 
jxofaltrds said:
250.66 Size of Alternating-Current Grounding Electrode
Conductor.
(A) Connections to Rod, Pipe, or Plate Electrodes.
Where the grounding electrode conductor is connected to rod, pipe, or plate electrodes as permitted in 250.52(A)(5)
or (A)(7), that portion of the conductor that is the sole connection to the grounding electrode shall not be required to be larger than 6 AWG copper wire or 4 AWG aluminum wire.

250.66 Note: Aluminum cannot be connected to an 8? ground rod.
Click to expand...
...and I remind you of the part I [additionally] emphasized...
 
Smart $ said:
Counterpoint is the depiction does not exemplify that. The service conductors could be 1/0 CU or 3/0 AL, or smaller.
Click to expand...

jxofaltrds said:
250.66 Size of Alternating-Current Grounding Electrode
Conductor.
(A) Connections to Rod, Pipe, or Plate Electrodes.
Where the grounding electrode conductor is connected to rod, pipe, or plate electrodes as permitted in 250.52(A)(5)
or (A)(7), that portion of the conductor that is the sole connection to the grounding electrode shall not be required to be larger than 6 AWG copper wire or 4 AWG aluminum wire.

250.66 Note: Aluminum cannot be connected to an 8? ground rod.
Click to expand...
Where did he mention connecting aluminum to the ground rod? His counterpoint mentions the depiction does not clarify a situation where 250.66 would otherwise require a GEC to be larger than 6AWG copper. The mentioned aluminum was the service conductor not the GEC.
 
jxofaltrds said:
Sole connection or not?

View attachment 9553

http://www.electricalnews.com/bridgeport-introduces-intersystem-ground-rod-bridge-clamp/
Click to expand...

Maybe, might depend on if the multiple terminations are used, and what they go to.

I still am not convinced either way that a 6 AWG to one rod - then continuing on to another rod is considered a single or multiple electrodes, and will say I have done it many times where a larger than #6 would be required if considered multiple electrodes.
 
Nice read:

http://www.iaei.org/blogpost/929497/170572/Sole-Connections?hhSearchTerms="ground+and+rod"&terms=

"Question: At 250.66(A) and (B), the Code refers to a "sole connection to the grounding electrode.? Please explain what sole connection means; and is the term sole connection defined anywhere in the NEC? PM"


....... "The plural language and revised text at both 250.66(A) and (B) should make it clear that the Code considers these two ground rods to be one electrode as far as the sole connection sizing provisions are concerned, and 6 AWG copper conductor could be used at both ground rods."
 
jxofaltrds said:
Nice read:

http://www.iaei.org/blogpost/929497/170572/Sole-Connections?hhSearchTerms="ground+and+rod"&terms=

"Question: At 250.66(A) and (B), the Code refers to a "sole connection to the grounding electrode.? Please explain what sole connection means; and is the term sole connection defined anywhere in the NEC? PM"


....... "The plural language and revised text at both 250.66(A) and (B) should make it clear that the Code considers these two ground rods to be one electrode as far as the sole connection sizing provisions are concerned, and 6 AWG copper conductor could be used at both ground rods."
Click to expand...
I'll concede that under the 2014 revision, only a #6 is required.

(A) Connections to a Rod, Pipe, or Plate Electrode(s).
Where the grounding electrode conductor is connected to
a single or multiple rod, pipe, or plate electrode(s), or any
combination thereof, as permitted in 250.52(A)(5)or (A)(7),
that portion of theconductor that is the sole connection to the
grounding electrode(s) shall not be required to be larger than
6 AWG copper wire or4 AWG aluminum wire.
Click to expand...
 
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