Water pipe as an electrode

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jghrist

Senior Member
I would consider that the well casing is permitted to be used as a grounding electrode by 250.52(A)(7) [2005 Code]

I would also consider it to be a supplemental grounding electrode for the pump, which could be connected to the EGC and would not be required to comply with the electrode bonding requirements, per 250.54. I can't see why bonding would be prohibited, though.
 
K8MHZ

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
billsnuff said:
are either water pipes (electrodes) within 5 ft of the entrance of the electrical supply?
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The well pump, definitely not. More like 25. As for the rest of the pipes.....maybe, maybe not. The entrance to the city system is no where near the service panel. It comes in from the street and enters about 30 feet from the panel. The two water systems are separated by about 6 inches. The separation was created by removing a nipple and capping off the open ends of the remaining pipes so that one end is fed by city water and the other by the well pump.
 
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LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
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Electrical Contractor
K8MHZ said:
I'll have you know that I weigh nearly 200 pounds and can bend 2 inch RMC over my knee.
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"Hulk not need bender!"​
 
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gndrod

Senior Member
Location
Ca and Wa
pump data....

pump data....

K8MHZ said:
The well pump, definitely not. More like 25. As for the rest of the pipes.....maybe, maybe not. The entrance to the city system is no where near the service panel. It comes in from the street and enters about 30 feet from the panel. The two water systems are separated by about 6 inches. The separation was created by removing a nipple and capping off the open ends of the remaining pipes so that one end is fed by city water and the other by the well pump.
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Hi Marky,

The inspector might be an old well pump setter and has observed something not mentioned here. The mention of the pump on 120Vac brings a question...Is the pump hardwired or plug-in? With the pump being above the well gives the impression that the unit is fixed in place like a jet-pump that would be installed over the well casing with a suction pipe into the well with a foot-valve. In either instance the well feeds back to the tank inside the house and the control needs to be hooked up to a pressure control within 4' of the tank.

The motor case needs to be bonded to the 120Vac egc that is also a common bond to the tank equipment. The feeder bonds the system to the main disconnect source or 4-wire subpanel. This may be the reason the inspector requires the isolation between the supplemental and the auxiliary electrodes to prevent a system loop potential. I am just guessing without more detail. Is this an accurate description of what exists?
 
K8MHZ

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
gndrod said:
Hi Marky,

The inspector might be an old well pump setter and has observed something not mentioned here. The mention of the pump on 120Vac brings a question...Is the pump hardwired or plug-in? With the pump being above the well gives the impression that the unit is fixed in place like a jet-pump that would be installed over the well casing with a suction pipe into the well with a foot-valve. In either instance the well feeds back to the tank inside the house and the control needs to be hooked up to a pressure control within 4' of the tank.

The motor case needs to be bonded to the 120Vac egc that is also a common bond to the tank equipment. The feeder bonds the system to the main disconnect source or 4-wire subpanel. This may be the reason the inspector requires the isolation between the supplemental and the auxiliary electrodes to prevent a system loop potential. I am just guessing without more detail. Is this an accurate description of what exists?
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Exactly!!

Please, tell me more. Where can I find NEC sections that support this?

Many Thanks!
 
G

gndrod

Senior Member
Location
Ca and Wa
K8MHZ said:
Exactly!!

Please, tell me more. Where can I find NEC sections that support this?

Many Thanks!
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Yer Welcome. Marti nailed it with [250.6] stopping objectionable current. Well systems notoriously lack adequate bonding for fault-current paths where grounding of tank manifold-pressure switch metal parts are 'floated' due being confused with electrode grounding of metal casing and pipes being adequate. Merry Christmas.
 
K8MHZ

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
gndrod said:
Yer Welcome. Marti nailed it with [250.6] stopping objectionable current. Well systems notoriously lack adequate bonding for fault-current paths where grounding of tank manifold-pressure switch metal parts are 'floated' due being confused with electrode grounding of metal casing and pipes being adequate. Merry Christmas.
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Ok, this may be an issue where some of the story got left out.

"If the use of multiple grounding connections results in objectionable current..."

If there was objectionable current resulting from the connection it wasn't told to me.

I don't see where there would be any objectionable current, however I am the type that if I were to sit down and draw it all out it would make more sense to me.

At least you guys pointed me to a part of the NEC that could apply and I thank you.

So before I make any assumptions, I think I need to ask the EC if the inspector happened to mention objectionable currents or not.
 
marti smith

marti smith

Senior Member
Good point: I was trying to find something that might relay an illustration of getting rid of a parallel path for grounding as I lack eloquence and clarity of explaning!
 
G

gndrod

Senior Member
Location
Ca and Wa
jxofaltrds said:
Trying to understand how connecting grounded conductors and EGCs relate to electrodes.
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Connecting grounded conductors to terminal grounds at the main service disconnect panel...yes, but to an auxiliary electrode (well case and pipe)...no. The NM egc must bond the metal parts back to the ac source (zero reference) for operating the OCPD's, not an electrode. Is there missing an alternate way here?
 
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