Well casing ground wire connection

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Chris75

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Is that lug approved for outdoor/external in the weather type use?


Yes, they are rated DB. (direct burial) I use them on pools all the time.

And how are you supposed to keep the mild steel casing for rusting under it.

I drill and tap the casing, I don't think anything wold stop the casing from rusting. but then again, thats not my problem either.


Also, the building ground is supposed to be 25 ohms or less or it is not acceptable.

Untrue, what that section is saying, is if you drive ONE rod and it does not meet 25 ohms, then you must drive a 2nd rod, thats it, since no one is gong to waste time and money getting the first rod tested to begin with, we just drive two rods and thats all thats required.

Years ago when I first heard of this "bond" or "grounding of the metal casing", it was explained as a building ground electrode because of changes in foundation construction and non metallic water lines that had historically been used in the past.

Nope, all were trying to do is keep the well casing from becoming energized by the pumps wiring, thats it.

Now you are saying it is for well worker protection although for decades there was no ground to a 2 wire submersible pump.

Thats correct, and your spot on, for years no EGC (equipment ground conductor) was not required, until guys started getting hurt/killed, thats usually why most codes end up in the book, unfortunately.

You also say this and ground rods etc. are for lightening strike protection. I hear that many people still suffer damage from lightening strikes, so how well do these bonds and/or grounds actually work for lightening protection or am I missing something?

Of course they still suffer damage, its lightning. But what the ground rod tries to prevent is surface arcing.
 
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Speedbump

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Untrue, what that section is saying, is if you drive ONE rod and it does not meet 25 ohms, then you must drive a 2nd rod, thats it, since no one is gong to waste time and money getting the first rod tested to begin with, we just drive two rods and thats all thats required.

Here in Florida it is extremely difficult to get a good earth ground by driving a 6' rod. Some Electric Co. grounds are way over a hundred feet.

My question is; what is the procedure for testing this 25 ohm resistance in a driven ground rod?

bob...
 

Chris75

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My question is; what is the procedure for testing this 25 ohm resistance in a driven ground rod?

bob...



Fall-of-Potential, 3-Point testing method.


But this is just useless in the resisdential world. Look at it this way, say you drove a ground rod and ended up with 1000 ohms resistance, are you seriously going to keep driving rods till you get to the magical number that nobody even knows why its 25 ohms to begin with? :D
 

Chris75

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Here in Florida it is extremely difficult to get a good earth ground by driving a 6' rod. Some Electric Co. grounds are way over a hundred feet.

My question is; what is the procedure for testing this 25 ohm resistance in a driven ground rod?

bob...


So with out proper testing, how do you know its difficult to get a good ground in florida? Also, 8' rods are required by the NEC.
 

Masterpumpman

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There's a lot of unnessary information here!

In years gone by most submersible pumps were run on galvanized pipe, therefore they were grounded by the water in the well. . .the best ground around. Ground rods weren't nearly effective.

Today submersible pumps are installed on PVC or Plastic. The pump motor is still the best ground, however this ground has no connection to the control box or fuse panel above ground.

Hence submersible pumps today are 2 or three wire pumps. A two wire pump has 3 wires, usually 2 black wires and 1 green wire.

A three wire pump (using a control box) has 4 wires, a red, a black, a yellow wire and a green wire (the ground to the pump motor below the water).

The green wire is always connected to the pressure switch ground lug, the control panel (if it has one) and the ground lug in the fuse/trip box.

I don't know what the individual states codes are, however the above use of the green wire on submersible pumps is the proper way to protect people; electrical system and help prevent lightning from damaging a pump!

From Franklin Electric: The primary purpose of grounding the metal drop pipe and/or metal well casing in an installation is safety. It is done to limit the voltage between nonelectrical (exposed metal) parts of the system and ground, thus minimizing dangerous shock hazards. Using wire at least the size of the motor cable wires provides adequate current-carrying capability for any ground fault that might occur. It also provides a low resistance path to ground, ensuring that the current to ground will be large enough to trip any overcurrent device designed to detect faults (such as a ground fault circuit interrupter, or GFCI).

Normally, the ground wire to the motor would provide the primary path back to the power supply ground for any ground fault. There are conditions, however, where the ground wire connection could become compromised. One such example would be the case where the water in the well is abnormally corrosive or aggressive. In this example, a grounded metal drop pipe or casing would then become the primary path to ground. However, the many installations that now use plastic drop pipes and/or casings require further steps to be taken for safety purposes, so that the water column itself does not become the conductive path to ground.

When an installation has abnormally corrosive water AND the drop pipe or casing is plastic, Franklin Electric recommends the use of a GFCI with a 10 mA set-point. In this case, the motor ground wire should be routed though the current-sensing device along with the motor power leads. Wired this way, the GFCI will trip only when a ground fault has occurred AND the motor ground wire is no longer functional.
 

Southern Man

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..... I'm still not sure any of us really knows exactly what goes on inside those copper wires.

bob...
:)
My Dad is a retired electrical engineer and when I ask him a question like that he always has the same one-word answer: "magic".

He also insists that the best ground to use is the largest metal object that you have buried in the ground. In this case it would be the steel well casing driven to bedrock.

But... he and I built a steel building one time with each of the frames bolted directly to a steel H pile driven an average depth of 260 through soft marl. Obviously the building was well grounded. The county inspector, however, made us ground the building with 10' copper clad ground rods.
 

Chris75

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In years gone by most submersible pumps were run on galvanized pipe, therefore they were grounded by the water in the well. . .the best ground around. Ground rods weren't nearly effective.

No they were not grounded, stop confusing the earth with something that is related to grounding a piece of equipment, it is not the same thing, nor with ever be.



Today submersible pumps are installed on PVC or Plastic. The pump motor is still the best ground, however this ground has no connection to the control box or fuse panel above ground.

So you obviously do not understand electricity. The pump motor is not the best ground... the egc that is run with the supply conductors is.


Hence submersible pumps today are 2 or three wire pumps. A two wire pump has 3 wires, usually 2 black wires and 1 green wire.

A three wire pump (using a control box) has 4 wires, a red, a black, a yellow wire and a green wire (the ground to the pump motor below the water).

The green wire is always connected to the pressure switch ground lug, the control panel (if it has one) and the ground lug in the fuse/trip box.

I don't know what the individual states codes are, however the above use of the green wire on submersible pumps is the proper way to protect people; electrical system and help prevent lightning from damaging a pump!

Has nothing to do with lightning.


From Franklin Electric: The primary purpose of grounding the metal drop pipe and/or metal well casing in an installation is safety. It is done to limit the voltage between nonelectrical (exposed metal) parts of the system and ground, thus minimizing dangerous shock hazards. Using wire at least the size of the motor cable wires provides adequate current-carrying capability for any ground fault that might occur. It also provides a low resistance path to ground, ensuring that the current to ground will be large enough to trip any overcurrent device designed to detect faults (such as a ground fault circuit interrupter, or GFCI).

And I agree with this....
 

Gary Slusser

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So Chris, since all pump manufacturers have been installing a ground pigtail on all submersible residential pumps for many years now, why is this ground of the casing needed?

And since you seem to not care if the lug attachment actually will work later after the casing rusts internally and externally and around the threads of the screw attaching the lug to the casing, IMO that will be giving folks a false sense of security just a year or so later when they go to work on the well and the rust has formed. Prior to this grounding to the casing everyone knew there was no ground on the pump and acted accordingly.

Also, where could we see some proof of the injuries and deaths you say is the basis for this ground on the casing? I ask because I've not heard of any over the last 20-40 years and a couple of Google searches I just did finds only one injury. Porky and Speedbump, have you heard of the injuries and deaths?
 

Chris75

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So Chris, since all pump manufacturers have been installing a ground pigtail on all submersible residential pumps for many years now, why is this ground of the casing needed?


Simple because the NEC requires it, I was not there when the code panel decided to add it to the NEC, but I can tell you that it only makes sense to bond it since it could become energized by the pumps wiring. And with the casing now bonded, it will trip the well pump breaker and keep someone from getting killed.


And since you seem to not care if the lug attachment actually will work later after the casing rusts internally and externally and around the threads of the screw attaching the lug to the casing, IMO that will be giving folks a false sense of security just a year or so later when they go to work on the well and the rust has formed. Prior to this grounding to the casing everyone knew there was no ground on the pump and acted accordingly.

Oh, but I do care. I just dont see your relivance with a little surface rust, The lug will be tight against the casing, I dont know how much rust will actually form between the two joints.

Also, where could we see some proof of the injuries and deaths you say is the basis for this ground on the casing? I ask because I've not heard of any over the last 20-40 years and a couple of Google searches I just did finds only one injury. Porky and Speedbump, have you heard of the injuries and deaths?

Look, I didnt write the NEC, I'm not on the code making panel either, but ANYONE, can request a code change or add a code if they wish, just by filling out a form. In other words, anyone could have requested the well casing to be required to be bonded to the pumps EGC. I just dont have the info that your requesting,

but lets face it, bonding the well casing is a no brainer in my opinion.
 

Speedbump

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Fall-of-Potential, 3-Point testing method.

Since I obviously don't know how this test is conducted, I asked you to explain it to me. I didn't care what it was called, I just wanted to know how the test was done.

My old friend (who I havn't seen in years) at TECO (our local power company) does these tests and puts in the ground rods. Last time I talked with him we got on the subject and that was when he told me how difficult grounding was here in our area. That's how I found out. Since, trying to get a good ground for several different reasons (one being Amateur Radio Antennas which need a good ground) I have also found out that grounding is not as simple as driving a copper clad spike 6' into the ground.

So if you do know how this test is done, I would appreciate you explaining it to me.

Gary, I have heard of people claiming to get tickled in the bath tub when the neighbors pump was shorted, but I don't know just how much of that is a wives tale. Otherwise, no I haven't heard of one single case in over 40 years of pump/well work.

bob...
 

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Chris; You don't seem cocky to me at all. Concise and accurate. Very very good job of sorting things out. There are so many misconceptions concerning bonding and grounding and what neutral is, and for many it gets confusing as hell. You have done a fine job of explaining things, you should teach. As for those that wish to argue your points that fine, everyone can dissagree. But in the end the code clearly outlines the proper procedure and that's the one we must all abide by if we want to avoid liability.
 

Chris75

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Chris; You don't seem cocky to me at all. Concise and accurate. Very very good job of sorting things out. There are so many misconceptions concerning bonding and grounding and what neutral is, and for many it gets confusing as hell. You have done a fine job of explaining things, you should teach. As for those that wish to argue your points that fine, everyone can dissagree. But in the end the code clearly outlines the proper procedure and that's the one we must all abide by if we want to avoid liability.


Thank you, and your correct, bonding and grounding is the hardest section in the code book to grasp, never mind trying to explain it over the internet. :D
 

Chris75

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Since I obviously don't know how this test is conducted, I asked you to explain it to me. I didn't care what it was called, I just wanted to know how the test was done.

Sorry, I just dont have the knowlege on the subject, I dont preform these types of test. I just dont have a reason to.
 

99k

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Chris; You don't seem cocky to me at all. Concise and accurate. Very very good job of sorting things out. There are so many misconceptions concerning bonding and grounding and what neutral is, and for many it gets confusing as hell. You have done a fine job of explaining things, you should teach. As for those that wish to argue your points that fine, everyone can dissagree. But in the end the code clearly outlines the proper procedure and that's the one we must all abide by if we want to avoid liability.


I agree. I am learning a lot from your commentary Chris. I have another question.
If the pump only has a slight leakage to ground (not enough to trip the breaker) and the pump to bonded, will this prevent the possibility of any strap voltage making its way back through the piping in the house and shock the occupants? What if we had the same scenario with leakage but the pump was not bonded? Would that shock the occupants?
I ask this question because my supplier of submersible pumps for storage tanks insists on the installation of a GFCI because the pumps do not have a UL approval (this is there CYA) but my customers do get nuisance trips from storms etc. Would a bonded pump in this case "trump" a GFCI and negate the need for it?
Thanks.
 

Chris75

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I agree. I am learning a lot from your commentary Chris. I have another question.
If the pump only has a slight leakage to ground (not enough to trip the breaker) and the pump to bonded, will this prevent the possibility of any strap voltage making its way back through the piping in the house and shock the occupants? What if we had the same scenario with leakage but the pump was not bonded? Would that shock the occupants?
I ask this question because my supplier of submersible pumps for storage tanks insists on the installation of a GFCI because the pumps do not have a UL approval (this is there CYA) but my customers do get nuisance trips from storms etc. Would a bonded pump in this case "trump" a GFCI and negate the need for it?
Thanks.


Nothing wrong with using GFCI's, yes, lightning tends to fry the electronics in them from time to time, but they will tell you that the pump is failing and its time for a replacement, UL only allows a certain amout of current leakage, so I agree with your pump supplier to provide GFCI protection.
 

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After many google searches I give up. Is there a special ground strap for the connection of the well casing to the ground wires of the pump wire circuit? My well cap is made of some sort of light alloy so it is not a candidate, nor does it have a grounding screw on it anyway. Drill a hole in the well casing for the bond?


I have been a licensed electrical journeyman for years, and I have yet to hear of anybody try to make any part of their electrical system a better ground to Earth than anything the power company installs. This is a recipe for disaster for attraction to lightning. The well cap just needs to have a simple ground strap bonded from the grounded conductor, not the pump or from a ground rod ever! The conductor being used to wire the well should have the conductor run with it if the electrical inspector requires it. The electrical circuit will pop the breaker using the neutral if the pump goes bad, the pump has the strap inside of it so it doesn't need additional grounding, the cap does though in some areas so the inspector maybe feels as if he did his job. Ground rods are an absolute bad thing and it is only because you may create a better ground that you do not want for the reason of lightning.

If a plumber installs a pipe ground that ties to a bonding system to an electrical panel, that really isn't their job, it is first the electrician's, as well, the electrical bonding and grounding of any well pump system the installer should be qualified to do so, and hold a license to install, like the licensed HVAC guy, he has to hold electrical credentials or hold a special license that would allow them to electrically connect the system,. The rule of thumb is to ground what is necessary but not make the resistance lower than it already is. If there is any indicating factor that would lead an electrician to believe that the power company's grounded neutral or center tap of the distribution transformer is not grounded effectively, nobody has any right to go grounding their home with a rod, reground their breaker box, meter can, swimming pool, or well better than the distribution system is.

I'll tell you all why:
The power company is to install (2) 10' copper clad 3/4" ground rods within 6 feet of any utility pole that services the home or the area. If the system is an underground system (my specialty), the transformer pad is to be grounded with two 10 foot ground rods, completely below grade at the depth of the trench which is a bare minimum of 24 inches from the grade for direct buried cables, or, 30 inches for conduit. The transformer pad by NEC code should have a completed ring bus of a minimum of a 1/0 copper bare stranded wire all the way around the transformer with two tails coming from the ground connected with mechanical tank grounds (threaded servits) to the case of the transformer. The center tap of the secondary side of the transformer is to bond with a heavy gauge multi layered copper graounding strap to tie the Earth to ground for safety of the resident, as well, for a path for the lightning arrestors on the high side (medium voltage elbows or station type lightning arrestors to safely discharge to ground)

All system components in a home are to be bonded in the panel to the neutral bus for the simple fact that the neutral makes it's way back to the transformer as a return. If the neutral wire is loose or burnt clear, the end result would be a safe path through the ground back to the source for return, which is usually through ground the imbalance load of the system only.

All components to be grounded, such as swimming pools, jacuzzis, etc. are not to have physical ground rods punched to the earth next to the pool because it makes the pool an attractant to lightning. The pool's components should be grounded with mechanical lugs, (for instance an above ground pool) one #10 or #8 green jacketed conductor, tied to every support beam, uncovered, then, tied to the mechanical lug on the pump, and connected to the connections thereafter place after place and connected to the neutral/ground bus. These connections all have resistance, and it is vital that the ground resistance measured from ground to the neutral is more than the ground connection at your box tested across the neutral.

The ground connection from the pool will have several connectors along the way from the breaker box to feed it's ground, then, back from the pool to the neutral/ground bus again. The added resistance assists with eliminating the pool from being struck by lightning.

The same goes for pipes, but, in most cases, cast iron or metallic pipe that is direct buried into the home, especially copper is grounded all at the same place, and the power company grounds should equal or be a better ground to be a less resistance to be the attractant for the lightning instead of a home or pool since it has the needed protection to safely discharge the bolt, a swimming pool does not , as well, kids swim in a pool.

If we carry a ground from our well back into our home, some wells are 300 feet deep. This would be a massive hazard as pipes, electrical boxes and outdoor receptacles would be a better choice for the bolt of lightning to hit, possibly killing a pool full of children, etc. Use your heads before you ground in a fashion it isn't supposed to be, like adding ground rods when they are not necessary. We have all of these rules for a reason, too bad they don't tell us why, that is why we go to school or have very extended bonified apprenticeship programs to follow.. A simple resistance check could be done but, a ground resistance meter is supposed to be used by the power company, or, is supposed to be used by the electrical contractor/personnel before trouble is started.

To check the resistance in the box, to the source, there may be an exposed ground next to the pole, or a down ground on the pole. The ground resistance meter is connected to this and also grounded a distance away, usually where other rods are driven. If a water pipe has a better earth than the power's ground, then by connecting them together in the street usually eliminates the issue. Like I said, connections add resistance and the connections are vital because they are engineered into the formula when the designs are studied originally . If lightning protection is used, it means there is either a massive change in topography, or, the ground has saturation making it a well suited spot to attract cloud to ground lightning.

I have one of these meters at my disposal, it is vital to use these when homes or any other dwelling is built in a sandy area. Some poles or transformer pads need excavation to bring the ground to a good spot that is actually an accepted and approved level to discharge lightning through a set of lightning arretors, and high voltage bleed off from shielded cables since they always slowly dissipate to the grounded sheath and it is very important to follow these guidelines. DONT GROUND MORE THAN NECESSARY. The fault current relies on a grounded conductor to be used for the breaker to pop, nothing more, but, it has to lead from your breaker box, not from a driven ground ever because a voltage drop would be created and the breaker is designed to open at the rated voltage, when voltages are reduced amperage climbs, netting the same wattage, but, the breaker isn't designed for wattage, it's designed for amperage at only a given voltage.

Marc
 
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