Driving ground rod through rock

[lakeroadster]

If the inspector says the work is acceptable, the homeowner did his/her part, hired a licensed professional, paid for a permit, the work was inspected and passed, so what else is the homeowner expected to do?

Nothing. Many times in life ignorance is bliss.

But if you are the kind of person who is on this forum be aware that if somebody says "we got a permit and it was inspected, so it meets code" it may indeed not meet code.

Every inspector is tasked with inspecting to the governing code. Sometimes that's the NEC, sometimes it's the IBC, or a PE stamped drawing, or a local spec that is stricter than a national code.

In this case there are very valid reasons to have the ground rod deep into the earth... and not just under the surface... and if the inspector says differently, tell him you are going to modify the drawings to meet his specifications and want him to sign and date it... you'll see him change his mind real quick.

"A driven ground rod must be buried at least 8 ft. in the ground. With an 8 ft. ground rod, the connection to the grounding electrode conductor must be made flush with the ground or below ground. If bedrock is hit when driving the rod, it may be installed at a 45 degree angle. When driving the rod at a 45 degree angle, if bedrock still prevents the rod from being driven, the ground rod may be buried in a trench which is at least 30 inches deep."
https://jadelearning.com/jadecc/courses/UNIVERSAL/NEC05.php?imDif=2424

 

[Ji m]

If there was ever a good question for a local inspection dept this is one.

^this

 

[TheEquineFencer]

LOL, 8ft pile of topsoil outside, drive it through the top of the pile....

 

[Lelandwelds]

Nothing. Many times in life ignorance is bliss.

But if you are the kind of person who is on this forum be aware that if somebody says "we got a permit and it was inspected, so it meets code" it may indeed not meet code.

Every inspector is tasked with inspecting to the governing code. Sometimes that's the NEC, sometimes it's the IBC, or a PE stamped drawing, or a local spec that is stricter than a national code.

In this case there are very valid reasons to have the ground rod deep into the earth... and not just under the surface... and if the inspector says differently, tell him you are going to modify the drawings to meet his specifications and want him to sign and date it... you'll see him change his mind real quick.

"A driven ground rod must be buried at least 8 ft. in the ground. With an 8 ft. ground rod, the connection to the grounding electrode conductor must be made flush with the ground or below ground. If bedrock is hit when driving the rod, it may be installed at a 45 degree angle. When driving the rod at a 45 degree angle, if bedrock still prevents the rod from being driven, the ground rod may be buried in a trench which is at least 30 inches deep."
https://jadelearning.com/jadecc/courses/UNIVERSAL/NEC05.php?imDif=2424

Fascinating reading guys. I do make an honest attempt to shut up and pay attention when I am clueless.

How big a deal is 12 inches vs. 96 inches if I have a lightning strike?

I have burned 7/16" E7024. I have been in a cross country sub station when the switch is closed. I have been close enough to a lightning strike to see bark fly.

I am aware how much power is there and I dont "play electrician". I already own two more ground rods. Should I be planning some holes?

 

[henrysgarage]

Here is a link to using a ground plate in place of a rod.
https://s2.renewityrma.com/leg2/FrontLines247Service/EU_S1c.asp?FaqID=24 and

https://s2.renewityrma.com/leg2/FrontLines247Service/EU_S1c.asp?FaqID=109

 

[Lelandwelds]

Here is a link to using a ground plate in place of a rod.
https://s2.renewityrma.com/leg2/FrontLines247Service/EU_S1c.asp?FaqID=24 and

https://s2.renewityrma.com/leg2/FrontLines247Service/EU_S1c.asp?FaqID=109

My internet toy doesnt like your links.

I have been reading the electrical forums about bonding jumpers and grounding rods. It reminds me of Clinton's husband arguing the definition of "is". Quoting code sections and arguing the meaning of "sole" and "a" in multiple sections. Ye Gods!

You guys arent so bad after all.

It appears I should add another grounding rod more than six feet away and connect it to the first grounding rod but never the electrical panel. If I cant hit less than a measured 25 ohm resistance, I can keep adding rods as long as I only connect them to each other and keep at least six feet apart.

It also seems fairly common to cut the damn thing off when you hit rock.

My last house had romex, cotton covered, and knob wiring. It had fuses and impossible to find circuit breakers. ( It had galvanized, copper, and three kinds of plastic water supply lines. It had cast iron, PVC, and clay bell pipe for waste water. ) ( Negative roof slope in one spot when it rains. Doors that wont latch when it hasnt rained. Sinks and tub that had to be replaced when a faucet died. Ceilings that fall in the very, very early morning.)

I never want house drama again. ( And yes, I had a home inspection.)

 

[rpcraft]

if worse comes to worse and you can get down 18 inches you may be able to use a ground plate but the rod is preferred because with the ground plate you also have to dig a hole about 2 x 3 feet wide. When I worked for a lightning protection company we used a fairly large jackhammer with the rod attachments and I would take an angle grinder and sharpen an 8 foot stretch of reinforcing steel rod to a sharp point, drive it in and then sink the copper rod right next to it. It was a pain in the *** and I hated it because it was double work but the steel rod usually did a good job of breaking the path and making a guide path for the copper rod to follow without getting too twisty, and this was down in the San Antonio area, where after about 12 inches you were already using the jackhammer to finish getting your 18 inch hole chipped out. Just go rent yourself a t yourself a heavier jackhammer, a good sturdy step ladder and an equally sturdy helper to help hold and guide it. Let the jackhammer do the work on the steel rebar and it will break the path up, and after that you should have a fairly easy time to get the copper bar in (sharpen the tip on it too so it is more prone to follow the path of the rebar.

 

[sberry]

I was hoping someone like Westom who is an engineer in this field I believe jumped in here and added a dollars worth. I wonder how much good it all does?
Back in the day no one fussed quite as much and often outbuildings and some services were installed with a single rod, not saying it met code but it was done regularly especially where they went right in to standing water lots of times, some p[laces dam near hit ground water with a rod. I have footing and rod in water to the acorn in one corner on a loading dock.
But some of these other places is about like the consensus that going to the camp site and driving a rod in to 18 inches of dry dirt for your travel trailer really doesn't help much.

 

[rpcraft]

Fascinating reading guys. I do make an honest attempt to shut up and pay attention when I am clueless.

How big a deal is 12 inches vs. 96 inches if I have a lightning strike?

I have burned 7/16" E7024. I have been in a cross country sub station when the switch is closed. I have been close enough to a lightning strike to see bark fly.

I am aware how much power is there and I dont "play electrician". I already own two more ground rods. Should I be planning some holes?

If you are just talking about grounding your electrical and plumbing loops then customarily I have only seen one ground rod used but that is why getting that one ground rod staked properly is super important.

 

[Lelandwelds]

When I worked for a lightning protection company we used a fairly large jackhammer with the rod attachments and I would take an angle grinder and sharpen an 8 foot stretch of reinforcing steel rod to a sharp point, drive it in and then sink the copper rod right next to it.

Well, that's new to me! They used to drill water wells by impact. In other countries, the rebar would be acceptable.

Drive a ribbed steel into rock was a PITA? Sir, you have a gift for understatement.

I used to install fence in my twenties with a Pionjar jackhammer. Physically toughest year of my life.

I wonder how much good it all does?
Back in the day no one fussed quite as much and often outbuildings and some services were installed with a single rod, not saying it met code but it was done regularly especially where they went right in to standing water lots of times, some p[laces dam near hit ground water with a rod. I have footing and rod in water to the acorn in one corner on a loading dock.

I was hoping it was a belt and suspenders thing. There's a code where you need to ground your engine driven welder frame to earth ground if you stay in one spot too long.

If you are just talking about grounding your electrical and plumbing loops then customarily I have only seen one ground rod used but that is why getting that one ground rod staked properly is super important.

Yes, well, I dont know everything about everything. ( Don't tell the wife.) This isn't the first time professional has not equaled qualified.

I use to lurk on an electronics forum. They discussed eliminating noise from different resistances from parts of a grounding system. With all the inductive and reactive loads my neighbors and I have, I learned it was peanuts. Tiny, tiny peanuts.

I am more concerned about fire, death, and destruction than noise on my occilliscope.

 

[ard]

40 years back Id drive it until it was bending, and the head mushroomed. Cut it off, beat it some more until mushroomed- call for inspection.

 

[strutaeng]

Wow, thanks for all the tips and recommendations.

So the garage is existing. I ran PVC that I dug to rock and then covered with 2" of concrete cover, more like 3-4", with caution tape then backfilled. I've got a buddy of mine that is a master electrician and he's helping me on out.
I had copper 1/2" diameter pipe that was used for ground. Don't know how deep that goes.

As fas as foundation for garage it appears to be just a slab, probably cast directly on the rock. It's roughly 25ft x25ft.

I tried with my Dewalt 22 lb SDS Max and ground rod driver and it as only went in another few inches, total embedment about 24". The end was very mushroomed. I cut off the rod, sharpened with an angle grinder and tried again 5 feet away, with same results.

My friend said in this area he drives them at an angle. I'm going to try that next.