Grounding Electrodes question (ground rods)

[Walking Anachronism]

While inspecting a service installation I noticed that the grounding electrode conductor (4 AWG) led out from the service equipment unfastened to a ground rod w/clamp from the ground/soil. From there it continued to a second ground rod. Perhaps the contractor wanted me to see the termination of the conductor at the rod, but the top edge of both rods are at least 2" above grade and also the bonding jumper between both of them is suspended in mid air. It looked really unprofessional. Since the rods were installed pretty much right in front of the service equipement (located on exterior side of bldg), the rods and jumper are practically a tripping hazard. They are definitely subject to physical damage.

NEC 2011 states in 250.53(A)(1), "If practicable, rod, pipe, and plate electrodes shall be embedded below permanent moisture level. "

Also 250.64(B) requires the conductor to be protected from physical damage.

Question: Would you interpret the first code reference (above) as the top edge of the ground rod buried under surface of ground, say 12" deep?

Also I'm thinking of having them relocate the first rod farther from the equipment, fasten the electrode conductor along the wall before reaching the first rod, and then bury the jumper to the second rod. (No. 4 AWG isn't required in that text to be run in conduit if not exposed.)

 

[Dennis Alwon]

IMO, the ground rods must be below grade unless they are 10' rods and the wire needs to be fastened down the wall. Generally I just bury the bonding jumper next to the building from one rod to the other. Note it does not need to meet any minimum depth as other conductors.

 

[K8MHZ]

We will leave the rod and connector an inch or so above grade so the inspector can see them. As soon as he does and gives it his blessing, they get pounded the rest of the way into the ground.

 

[Dennis Alwon]

We will leave the rod and connector an inch or so above grade so the inspector can see them. As soon as he does and gives it his blessing, they get pounded the rest of the way into the ground.

Why not go below grade and leave the connection point exposed. I would hate to have to go back to pound it back in.

 

[Walking Anachronism]

Thanks for your comments they were helpful. Dennis, that's the way I'd like it done. (Why can't the contractor just leave it below grade with termination exposed?) They can fill around it afterward.

As far as 250.53(A)(1) goes I figure the the language 'permanent moisture level' basically means to ensure the rod extends below the frost line due to the resistivity of ice.

 

[dhalleron]

We will leave the rod and connector an inch or so above grade so the inspector can see them. As soon as he does and gives it his blessing, they get pounded the rest of the way into the ground.

I just leave a small hole and a pile of dirt. After it is inspected, I can swing by and knock the dirt in with my boot. No tools needed. Most of the time my dirt is still there when I go back.

 

[K8MHZ]

Why not go below grade and leave the connection point exposed. I would hate to have to go back to pound it back in.

We don't go back. We are always there for the inspections. We found that if we pounded them all the way in and just left a hole around the connection point, the hole would usually get filled and that was more work.

 

[Dennis Alwon]

We don't go back. We are always there for the inspections. We found that if we pounded them all the way in and just left a hole around the connection point, the hole would usually get filled and that was more work.

Gotcha-- I rarely ever meet the inspectors.

 

[cowboyjwc]

We ususally see them sticking up here, but many times there is a patio or walkway there so they couldn't bury the connector with out chipping out concrete and then patching the hole.

That being said, I should justify that statement by saying that on new construction we require a UFER ground, so we usually only see ground rods on panel change's.

 

[infinity]

Thanks for your comments they were helpful. Dennis, that's the way I'd like it done. (Why can't the contractor just leave it below grade with termination exposed?) They can fill around it afterward.

As far as 250.53(A)(1) goes I figure the the language 'permanent moisture level' basically means to ensure the rod extends below the frost line due to the resistivity of ice.

No one seems to know what "If practicable, rod, pipe, and plate electrodes shall be embedded below permanent moisture level" actually means. IMO the rod needs to go into the ground 8' and nothing more.

 

[GoldDigger]

NEC 2011 states in 250.53(A)(1), "If practicable, rod, pipe, and plate electrodes shall be embedded below permanent moisture level. "

I see permanent moisture level as a reference to the level at which the soil remains moist even at the end of the dry season. That would be above the water table, which is the level at which water would actually begin to fill in a hole. That could be above the frost line, IMHO. Or the frost line (where the soil temperature goes below 32F) could be above the lowest moisture level seen in the summer.

Where the permanent moisture level is would depend on things like climate, soil type, and maybe even whether there is a lawn sprinkler that keeps the area moist all the way up to the surface. Or a septic tank leach field for that matter.
Also note, that as bicyclists looking at the Motor Vehicle Code often find important, "practicable" is not synonymous with practical, nor does it mean remotely possible. It is probably somewhere in between.

 

[acrwc10]

"If practicable", I would interpret as "if it can be done, it will be done", there are areas that 8 ft down is bone dry. In that case drive 2 rods and be done with it. The issue I have with any of the ground rod being left above grade is, will it be an impalement hazard? Enough people have been injured falling on rebar that you now have to put big plastic caps on the ends if they are exposed,during construction, how is a ground rod any different?

 

[GoldDigger]

The issue I have with any of the ground rod being left above grade is, will it be an impalement hazard?

Or a tripping hazard.
I would be less concerned if the rod were 4" from the wall and under a surface mounted meter main than if it was 12" or more from the wall and next to a walkway. And it would depend on the details of the area where it is located. But I agree that it is not a great idea, and if you need to make a rule to avoid frequent decisions, then burying it completely seems to be the better choice.

 

[iwire]

If it is an 8' rod it is a violation to have any of it sticking up. It is required to be in contact with 8' of earth.

 

[mike1061]

Around Chicago we leave them a few inches above ground.
An inspector once told me that I could not cover the ground connection to the water pipe with drywall. That even ground connections are a connection and there for need to be acessable. So I thought the same applied to the connection at the ground rod.
Thanks
Mike

 

[infinity]

Around Chicago we leave them a few inches above ground.
An inspector once told me that I could not cover the ground connection to the water pipe with drywall. That even ground connections are a connection and there for need to be acessable. So I thought the same applied to the connection at the ground rod.
Thanks
Mike

Connections to rods, plates, ground rings and CEE's are permitted to be buried.

 

[K8MHZ]

Connections to rods, plates, ground rings and CEE's are permitted to be buried.

The connectors need to be marked DB, though.

 

[mike1061]

Got it.
Thanks
Mike

 

[acrwc10]

The connectors need to be marked DB, though.

Really any ground clamp that is in a wet location should be DB (even above grade), because the screws on the other ones rust out over time.

 

[electricmanscott]

Other mentioned issues aside, the connection to the rod is required to be flush with or below ground level unless you protect it from physical damage. It would be foolish to build something to protect two ground rod ends rather than just drive them flush.