Well Casing Grounding

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derwith

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I am a retired electrician and helping my daughter build her house. The well driller would not let me ground his well casing from the service panel to his well casing about a foot above grade with a #4 bare wire.

My question is: Is the well casing required to be grounded by the NEC? The pump motor has the green ground wire and he used 12/3 UF to go back to the controller with the ground wire connected.
 
Re: Well Casing Grounding

I don't believe the well-casing is required to be grounded per the NEC, however I do feel it is required to be bonded to the pump EGC per Section 250.112(M)
 
Re: Well Casing Grounding

Well diggers/plumbers always run the pump feed with the water line. Why would I want to set up an appointment to be there with the well guy so I can run conduit/cable while the trench is open?

Question for the original poster: Why would you want to bond the casing to the service with #4?
 
Re: Well Casing Grounding

His objection was: that if I grounded the well casing, lightning would destroy the pump motor. This makes no sense to me. He would not guarantee the pump motor if the casing was grounded.
 
Re: Well Casing Grounding

To start with, the well casing is already grounded as it is in contact with earth. Its not the well casing you are trying to ground. The idea is to ground the electrical system to something the serves as earth.

Lighting is going to strike and possibly destroy the well pump regardless of whether it is bonded and or connected to the electrical system. That excuss doesn't work.

I don't see what purpose running a #4 conductor fro mthe service to the well casing will serve. If other grounding means are available at the the service location, that will be more than sufficent. Ensure the well casing is bonded to the branch circuit EGC that is feeding the well pump and you are all set.
 
Re: Well Casing Grounding

The 200 amp Electrical service has two 5/8 x 8 ground rods installed. These went down, in sand, with very little effort. My mission was to provide a better (lower resistance) service equipment ground to divert lightning and surges to that 40 ft of well casing.

A number of years ago I got a service call from a customer complaining that he was getting electrical shocks from his pool ladder.

After troubleshooting his pool electrical system, I found that his neighbors well casing was causing the problem.

His neighbor had a 60 amp main, range and 4 service with one ground rod. The well installer wired his pump (no ground wire) through only one set of contacts of the pressure switch.

In the mean time the always hot pump conductor shorted to the well casing causing the current to go through the in ground pool (least resistance) and back to the pole transformer. The resistance was high enough to not trip the neighbors pump circuit breaker.

If the well casing had a good ground, the breaker would have tripped and the hazard would have been avoided.

In the end my customer was happy not getting shocks from his pool ladder and his neighbor was happy with a lower electric bill.
 
Re: Well Casing Grounding

I see one possible problem.
If the case is bonded to the pump and the pump is grounded by #12 back to panel.In the event we were to lose our neutral the steel well case would try to be the return.
Now the problem.Just how much current could #12 take before opening and now we have an even more dangerious situation with no ground wire.
I vote that the # 4 is a good idea but not required.
How many of you have seen the melted ground wires on old 12-2w/g when they had a reduced sized ground wire?
 
Re: Well Casing Grounding

Since when is a well casing not an underground metal water pipe? If it is available on the premise it should be used as an underground metal water pipe electrode. I know that I am a fanatic on this issue but I run a bare number two directly buried to the well casing if the underground portion of the conductor will be twenty or more feet in length. I run that GEC at the same depth as the water line or thirty inches whichever is greater. Every time I do this on rural properties I see a reduction in surge and spike damage.
--
Tom
 
Re: Well Casing Grounding

In washington state a metal well casing is considered a metal underground water pipe and is treated as a grounding electrode if within ten feet of the building. I always bond the service to the metal well casing, some well casings are 700 feet deep and make an excellent grounding electrode. But you still have to install a ground rod or rods.
 
Re: Well Casing Grounding

I wish there was a code requirement to use a well casing (more that 10 feet from the building)as a grounding electrode.

Then the well driller could not prevent me from connecting to his well casing.
 
Re: Well Casing Grounding

I find it amusing that people will only perform bare minimum requirements, especially where safety is a concern.
 
Re: Well Casing Grounding

I don't think there is any evidence that using a well casing as an GEC will provide additional safety. I find it to simply be another source of stray voltage as it becomes a parallel path for normal current. Bonding is really all that is needed. I think in years to come community and private underground water pipes will not be permitted to be used for the GEC. Just my opinion.
 
Re: Well Casing Grounding

well(no pun intended) if it was my house i think i would pick a 4 inch gal. conduit (pipe) 100 feet in ground over that ground rod 9 ft deep every day of the week ;) somethink tells be its a better ground
 
Re: Well Casing Grounding

I think that according the previous post about getting shocked from a pool ladder at an adjacent property, it is imperative that all well casings are grounded with a low impedance path back to the source. Having stray currents trying to find their way back through the ground is not good.
 
Re: Well Casing Grounding

A low impedence path won't necessarily reduce stray currents, as a matter of fact it could increase them.

I see this problem with pools. The EGC to the pool equipment is connected to the #8 pool bonding conductor. The pool effectively becomes a GEC and carries a good percentage of normal operating current. Removing the connection between the bonding grid conductor and the pool equipment EGC eliminates the problem.

A well casing will do the same thing. By providing a low impedance path, normal current will flow, possibly enough to cause step potentials around the well itself. A lower impedance path like the EGC will reduce the normal current flow, but still have a low enough resistance to clear a ground-fault.
 
Re: Well Casing Grounding

Bryan,
The pool effectively becomes a GEC and carries a good percentage of normal operating current.
Click to expand...
Why would it be carrying a "good percentage" of the current? What do you mean by a "good percentage"?
Don
 
Re: Well Casing Grounding

The purpose of the low impedance is to have the fuse or circuit breaker interrupt the circuit. The same function the ground wire in romex is there; to take the fault readily back to trip the circuit
 
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