Danger from a disconnected Ground Rod?

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Minuteman

Senior Member
I must admit, the whole ground rod issue was something I misunderstood, until the articles about Grounding vs. Bonding. Now it makes sense to me.

So, what danger to life is there at a home, if a ground rod wire is disconnected? Say that the neutral is properly bonded with a EGC and so is the water pipes and other metal equipment.

As I understand it, if the ground rod should become accidentally disconnected, there would not be any clear and present danger to the occupants of the home, only maybe the utility transformer during a lighting strike. Right?
 

dereckbc

Moderator
Staff member
Location
Plano, TX
The answer is yes and no. Depends on the situation.

Under the circumstances you outlined where a metal water pipe is used, the driven rod serves no real purpose other than NEC redundant requirements. Removing it would not alter lighning performance one bit because the water pipe is a supperior earth ground.

The danger is when you have an open or high impedance nuetral circuit from the transformer on grounded systems, or any ungrounded system. On the grounded system just using driven rods would present a real hazard to the building or structure. As the joke goes always have the apprentice disconnect the GEC
 
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Minuteman

Senior Member
Okay, so A/C guy (my friend) replaces a unit at a house and doesn't pull a permit. AHJ hammers him for not pulling a permit and also nails him for disconnecting the ground rod. (Panel is outside and the acorn nut came loose from the rod. He was the last one in the panel, so it's his fault.) It's in a suburb town with only two inspectors.

I agree that he should be punished for not pulling a permit. However, the AHJ says that he will loose his license to work in the small suburb for the "life safety" violation.

Is this a "life safety" issue?
 

cschmid

Senior Member
I agree no apparent danager unless you never found it and the other source became open then you would see unstablized voltage during your peak load times..No this is not a life safety issue..

Edited to add last statement..
 
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Minuteman

Senior Member
cschmid said:
I agree no apparent danager unless you never found it and the other source became open then you would see unstablized voltage during your peak load times..No this is not a life safety issue..

If the neutral connection failed, the ground rod and water pipes are not going to carry the neutral load. So, finding the ground rod disconnected has no effect on load.

Nothing about this says, "life safety".
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
The safety issue is when the building feed comes into contact with the utility primary or there is a close by lightning strike. In these cases the lack of a grounding electrode at the service can be dangerous.
 

cschmid

Senior Member
I believe there is more to this picture then what meets out eyes..I think the inspector has a hard on for this guy..yet Don is correct during a lightening strike it is dangerous but under normal conditions which 99.5% of the time it is no big deal..but I can not judge the installer or his actions as I know not of him or the situation more than described..
 

Minuteman

Senior Member
Okay, so it's a million-to-one odds that a lightning stike or the primary line conntacting the secondary.

I'm needing some info to give my A/C buddy to defend himself.
 

Cavie

Senior Member
Location
SW Florida
Minuteman said:
Okay, so it's a million-to-one odds that a lightning stike or the primary line conntacting the secondary.

I'm needing some info to give my A/C buddy to defend himself.

I think he should also have to replace the rotten post holding up the front porch. How about the loose porch railing? What, no smoke detectors!! make him install them too. The A/c has nothing to do with the grounding of the panel. The inspector is asking him to work outside the scope of his license.
 

Minuteman

Senior Member
Cavie said:
I think he should also have to replace the rotten post holding up the front porch. How about the loose porch railing? What, no smoke detectors!! make him install them too. The A/c has nothing to do with the grounding of the panel. The inspector is asking him to work outside the scope of his license.

No, it is just a spitting contest. The inspector had A/C guy's licensed pulled and used the ground wire as his reason.

I say, some punishment is warranted, but taking his license overboard. My buddy just needs some ammo to defend the ground rod issue.
 

dereckbc

Moderator
Staff member
Location
Plano, TX
Minuteman said:
If the neutral connection failed, the ground rod and water pipes are not going to carry the neutral load. So, finding the ground rod disconnected has no effect on load.

Nothing about this says, "life safety".

OK this is where it depends. If the water pipe is metalic, you share a transformer with a neighbor, the neutral current would flow back to the transformer via water pipe if the nuetral conductor opened, and the owner would likely never notice a problem. Also the the CATV coax can carry the current. Both conditions are dangerous.

The right answer is YES disconnecting the GEC can be dangerous under the right conditions.
 

Cavie

Senior Member
Location
SW Florida
Minuteman said:
No, it is just a spitting contest. The inspector had A/C guy's licensed pulled and used the ground wire as his reason.

I say, some punishment is warranted, but taking his license overboard. My buddy just needs some ammo to defend the ground rod issue.

I'll say it again, he has no issue. Even if he had pulled a permit, the grounding of an existing or new panel is not his legal problem. Making him repair the ground rod/egc connection is making him do work outside the scope of his license. Unless the inspector can prove the A/C guy removed the clamp, He should (1) inform the homeowner of the problem (2) Ask the A/C guy if he would please repair the connection. Or do it himself.
 

cschmid

Senior Member
Now we have an issue here..there is more than meets the eyes to this one why does the inspector have it in for this guy..repeated violations of no permits and in our state you can do the ac work but need an electrician to hook and unhook a/c unit..now we can not determine bad blood but the only way you are going to get any respectable weight in this one is by going to an electrical engineer and paying for him to write a statement regarding the purpose of the rod and the dangers associated with it..your friend will have no credibility in this area..I hope it was an electrical inspector hassling him and can you tell me why he is doing mechanical inspections..little out of his scope of work..I hope this witch hunt does not turn the opposite direaction..witch hunts are a 2 way street so the hunter hopefully does not become the hunted..has the inspector ever done the hand the permit without looking thing..Like a wise man once said when throwing stones you best not live in glass house..
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Semi-Retired Electrical Engineer
Riddle me this: If you refuse to wear a seat belt while you are driving alone in your car or truck, are you placing the lives of ?innocent people? (meaning not the one who is driving your vehicle) at risk? We know you would be risking your own life and health, and in my state at least you would be risking a $100+ ticket, but would you be risking anyone else?s life or health?

My answer is the same answer I would give to the question of the ?life safety? risks associated with disconnection of a ground rod. Yes, it is a risk. But the circumstances that would have to line up, for the risk to turn into an actual injury (or worse) are numerous, and are unlikely to all occur at the same time and place. From this I conclude that there really is no ?life safety? risk in either scenario.

Why do I see a risk to others, if you don?t wear a seat belt? Because not all collision events terminate immediately after the initial impact. The vehicles involved do not always come to an instant and complete stop. If you are not wearing your seat belt, the initial impact might knock you unconscious, or at least stun you enough to prevent you from discerning your situation and taking any remaining action that might need to be taken. In that case, your car might still be in motion, and you might not know it, and there might be a person standing in the car?s path with their back to your car (i.e., they are looking at the other cars involved in the collision), and you won?t be able to put on the brakes in time to prevent your car from hitting that person. Unlikely? Yes. Many things have to all go wrong at the same time before a person would really be injured in this manner? Yes.

For a ground rod with its GEC disconnected to place a person?s life or safety at risk, many circumstances would have to go wrong, all at the same time. First, it would have to happen in a house with plastic water pipes, or at least one with no metal piping going from inside to a point at least ten feet into the ground beyond the house. Secondly, it would have to happen in a house with not one other metal object that is both bonded (in some way) to the N-G point in the service panel, and (in some way) connected to the dirt surrounding the house. In other words, there is no danger whatsoever, if there is at least one other point within the house that constitutes an effective ground point, even if the NEC would not give you credit for that method of grounding the service. Third, there would have to be some event that raised the voltage level between the (now ungrounded) ?grounded conductor? and planet Earth to a dangerous level. Lightning might do the trick, but how likely is that? Finally, a person would have to be in contact with a metal object while barefoot (or in general not wearing shoes that have adequate electrical insulation properties) during the time period in which the voltage on the grounded conductor is elevated. Unlikely? Yes. Many things have to all go wrong at the same time before a person would really be injured in this manner? Yes.
 

brian john

Senior Member
Location
Leesburg, VA
Hire a testing firm, measure ground resistance, measure current on ground electrode, have them write a letter stating what they found and what is posted here, get a few Grounding books that explain why electrodes are driven. I forget and to lazy to re-read was the electrodes supplemental?

Go over this guys head and POLITELY explain the situation, to the parties in charge. Explain how this inspector is correct but over reacting (MAYBE).

The problem for me is there are times where this could be an issue. .0000001 may be the odds but, I would not want to hang my license on those odds.
 
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