Am preparing to have my local electric company run new underground service to my new shop. Problem is I have dug 15" below my foundation and have hit solid rock. Probably going to rent a jack hammer to break out the rock down to 30" deep to meet code. Any suggestion on how to drive/drill the 8' grounding rod into the rock? Thanks
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Grounding Rod/New Service into Bed Rock
- Thread starter flyfish13
- Start date
Steevo
Well-known member
Get a ladder and use the jack hammer to drive the rod in?
wyliesdiesels
Well-known member
If u hit rock then youre allowed to dig a horizontal trench, bend the rods at 90deg angle and back fill. Dont recall the depth though!
If u hit rock then youre allowed to dig a horizontal trench, bend the rods at 90deg angle and back fill. Dont recall the depth though!
I'll see if I can find out what the depth needs to be.
awdblazer
Well-known member
can you used ground plates?
Speedy Petey
Well-known member
If this new, and there is rebar in the concrete, you would have had to use it as a Ufer and no ground rod would have been necessary.
If you are going to use the ground rod, just attach the wire to it and throw it in the trench. Done.
No need to bend the end up either. Wylie, does your area require this?
If you are going to use the ground rod, just attach the wire to it and throw it in the trench. Done.
No need to bend the end up either. Wylie, does your area require this?
If this new, and there is rebar in the concrete, you would have had to use it as a Ufer and no ground rod would have been necessary.
If you are going to use the ground rod, just attach the wire to it and throw it in the trench. Done.
No need to bend the end up either. Wylie, does your area require this?
Will it pass inspection doing it this way?
Stuart in MN
Well-known member
Will it pass inspection doing it this way?
That's a question for the local electrical inspector. We don't know what state (or country for that matter) you're in so it's difficult to provide good advice.
That's a question for the local electrical inspector. We don't know what state (or country for that matter) you're in so it's difficult to provide good advice.
United States of America.
State of Oklahoma
Here's a map got your reference
http://www.freeworldmaps.net/northamerica/united-states/political.html
It depends on what code cycle you are on. In some states (2011 code) if new construction you must be tied to rebar in concrete. I think Massachusetts is making folks jack hammer concrete to get tied to rebar if it wasn't done to begin withWill it pass inspection doing it this way?
It depends on what code cycle you are on. In some states (2011 code) if new construction you must be tied to rebar in concrete. I think Massachusetts is making folks jack hammer concrete to get tied to rebar if it wasn't done to begin with
2011....my building was bonded to the rebar in the footing but as I understand it I am still required to have a 6' grounding rod.
BillK
Well-known member
FF,
Th ONLY person who can correctly answer this question for you is your local inspector, period. Guys here can tell you what is required in their area or what is required by the NEC etc etc but if your inspector wants you to hang the ground rod from a fishing pole suspended by the roof .... that is what you will have to do. I know that we all would love for everyone to use the same rules, but basically it don't happen that way. Call the inspector and he will give you the only correct answer that you need.
Th ONLY person who can correctly answer this question for you is your local inspector, period. Guys here can tell you what is required in their area or what is required by the NEC etc etc but if your inspector wants you to hang the ground rod from a fishing pole suspended by the roof .... that is what you will have to do. I know that we all would love for everyone to use the same rules, but basically it don't happen that way. Call the inspector and he will give you the only correct answer that you need.
Aceman
Well-known member
2011....my building was bonded to the rebar in the footing but as I understand it I am still required to have a 6' grounding rod.
Did you verify this with your inspector? If you have a UFER ground already the NEC doesn't require you to add another grounding electrode(rods, etc).
spotco2
Well-known member
Don't know codes but do know that a jackhammer will drive those rods through rock pretty easily, at least around here. A Hilti hammer drill does a good job also.
Be sure to slide your clamp on the rod before driving it in the earth. Once you mushroom the end of the rod it's a pain to get the clamp on.
Be sure to slide your clamp on the rod before driving it in the earth. Once you mushroom the end of the rod it's a pain to get the clamp on.
Did you verify this with your inspector? If you have a UFER ground already the NEC doesn't require you to add another grounding electrode(rods, etc).
Yes...he said it was only an additional bonding for the building and that I still needed a grounding rod. My builder did weld the rebar in the footing to a vertical rebar that the inspector placed in the footing upon inspection and then he welded it to the building....does not sound as extensive as what a UFER ground would require.
FF,
Th ONLY person who can correctly answer this question for you is your local inspector, period. Guys here can tell you what is required in their area or what is required by the NEC etc etc but if your inspector wants you to hang the ground rod from a fishing pole suspended by the roof .... that is what you will have to do. I know that we all would love for everyone to use the same rules, but basically it don't happen that way. Call the inspector and he will give you the only correct answer that you need.
Thanks BillK.
Don't know codes but do know that a jackhammer will drive those rods through rock pretty easily, at least around here. A Hilti hammer drill does a good job also.
Be sure to slide your clamp on the rod before driving it in the earth. Once you mushroom the end of the rod it's a pain to get the clamp on.
Thanks for the advice.....rented a jackhammer this evening to hammer out the rest of the rock for the 3" 90.....will try to jackhammer the grounding rod tomorrow.
wyliesdiesels
Well-known member
can you used ground plates?
IIRCC, ground plates are ONLY used in Canada!
There are PoCo's who will not accept a UFER grounding electrode, I think they are in the dark ages but after a inspector passes a service it still has to meet PoCo specs, & they will get their way. Contact the PoCo to find out.
Aint that the truth! Ive had the unfortunate pleasure of dealing with a few of the inspectors at PGE.
If this new, and there is rebar in the concrete, you would have had to use it as a Ufer and no ground rod would have been necessary.
If you are going to use the ground rod, just attach the wire to it and throw it in the trench. Done.
No need to bend the end up either. Wylie, does your area require this?
Now that u mention this, I see its not required to bend the rod at 90deg. When i did electrical work in Santa Cruz county it was required. Maybe they just wanted the end of the rod out of the ground so they could see the bond? I'm living in the central valley now and havent yet had the unfortunate pleasure of hitting rock will driving in a ground rod.
Thanks for the advice.....rented a jackhammer this evening to hammer out the rest of the rock for the 3" 90.....will try to jackhammer the grounding rod tomorrow.
You might want to check with the inspector to see if only one rod is required. The NEC only requires one rod IF the rod has a resistamce of 25ohms or less to earth(the equipment to do this is expensive!) Some AHJ are picky and require this. Otherwise, 2 rods will have to be put in, 6' apart, with one continous GEC(grounding electrode conductor)...
Last edited:
alfredeneuman
Well-known member
Ground Plates are addressed in the NEC, under other acceptable electrodes, in Article 250.52 (A)
(6) Other Listed Electrodes. Other listed grounding electrodes
shall be permitted
(7) Plate Electrodes. Each plate electrode shall expose not
less than 0.186 m2 (2 ft2) of surface to exterior soil. Electrodes
of bare or conductively coated iron or steel plates
shall be at least 6.4 mm (1⁄4 in.) in thickness. Solid, uncoated
electrodes of nonferrous metal shall be at least 1.5 mm
(0.06 in.) in thickness
(6) Other Listed Electrodes. Other listed grounding electrodes
shall be permitted
(7) Plate Electrodes. Each plate electrode shall expose not
less than 0.186 m2 (2 ft2) of surface to exterior soil. Electrodes
of bare or conductively coated iron or steel plates
shall be at least 6.4 mm (1⁄4 in.) in thickness. Solid, uncoated
electrodes of nonferrous metal shall be at least 1.5 mm
(0.06 in.) in thickness
Tried jack hammering grounding rod in two different place. Went about 3 feet down with ease in both places and then to a dead stop. Guess I will call the code inspector on Monday and see what other options he will let me do.
justsam
Well-known member
Tried jack hammering grounding rod in two different place. Went about 3 feet down with ease in both places and then to a dead stop. Guess I will call the code inspector on Monday and see what other options he will let me do.
Good call! Whether he is right, wrong, or indifferent, his opinion is the only one that matters! He will respect you for asking before proceeding with plan B.
Speedy Petey
Well-known member
If your inspector told you this it is either a local amendment or he is wrong and wants it anyway.2011....my building was bonded to the rebar in the footing but as I understand it I am still required to have a 6' grounding rod.
Ask him for an actual code reference, not just what he wants. It is NOT required by the NEC.
Speedy Petey
Well-known member
His opinion matters, but it IS NOT enforceable unless it is written in the code.Good call! Whether he is right, wrong, or indifferent, his opinion is the only one that matters! He will respect you for asking before proceeding with plan B.
He is a code enforcement office, not a code-maker-upper officer.
His opinion matters, but it IS NOT enforceable unless it is written in the code.
He is a code enforcement office, not a code-maker-upper officer.
Thanks Speedy. I talked to an electrician in my area today and he said that I could put the 8' grounding rod in the trench with the main service line (since I am unable to drive it in with the bedrock issue). Others have referred to doing this but is it against "code"?
Sounds like all the sparky guru's have chimed in to resolve grounding rod.
OP you can update you GJ Profile with at least country and state (ie Oklahoma) and next time you'll get best advice for local codes as fellow GJer's can provide.
Also GJ likes pics, so show off your new shop !! You can edit the first post and Go Advanced, then Manage Attachments to attach up to 7 pics per post.
OP you can update you GJ Profile with at least country and state (ie Oklahoma) and next time you'll get best advice for local codes as fellow GJer's can provide.
Also GJ likes pics, so show off your new shop !! You can edit the first post and Go Advanced, then Manage Attachments to attach up to 7 pics per post.
Speedy Petey
Well-known member
The only code issue here is that the trench might not be 30" deep. I highly doubt this is something to get failed over though.Thanks Speedy. I talked to an electrician in my area today and he said that I could put the 8' grounding rod in the trench with the main service line (since I am unable to drive it in with the bedrock issue). Others have referred to doing this but is it against "code"?
At the same time, we still do not know if this supplemental rod is even required, or the whim of an inspector.
ddawg16
Well-known member
Funny thing about the Ufer ground.....it was developed during WWII but is only now really getting some attention......
http://en.wikipedia.org/wiki/Ufer_ground
If your inspector is even close to up-to-date....Ufer should be fine....and is fact, the best way to go.
On my 2-story addition....all of my rebar is bonded to my Ufer ground...which is a 20'+ length of copper wire at the bottom of my footing. Along with that, I have the 8' ground rod at the front of the house bonded to my metal water line coming into the house...and that is bonded to another 8' ground rod in the ground under the new crawl space....and that is bonded to the 'other' end of the 20' copper wire at the bottom of my foundation.
My foundation is 'well grounded'....
As far as I know, the only way you can get by with the rebar being your Ufer...is if you can show at least 20' of connected rebar...
The problem with using just rebar as an Ufer is that it's quite easy for the rebar tied to other parts of the rebar to become 'electrically' disconnected.
http://en.wikipedia.org/wiki/Ufer_ground
If your inspector is even close to up-to-date....Ufer should be fine....and is fact, the best way to go.
On my 2-story addition....all of my rebar is bonded to my Ufer ground...which is a 20'+ length of copper wire at the bottom of my footing. Along with that, I have the 8' ground rod at the front of the house bonded to my metal water line coming into the house...and that is bonded to another 8' ground rod in the ground under the new crawl space....and that is bonded to the 'other' end of the 20' copper wire at the bottom of my foundation.
My foundation is 'well grounded'....
As far as I know, the only way you can get by with the rebar being your Ufer...is if you can show at least 20' of connected rebar...
The problem with using just rebar as an Ufer is that it's quite easy for the rebar tied to other parts of the rebar to become 'electrically' disconnected.
We do several ground rods for tower sites in bed rock all the time . What you need is a SDS 1'' max bit that is 3' and several 24'' extensions. You need ground bed enhancement material or electro ground bed kit that can be purchased from any large electrical outlet or tower supply house like Site pro.
The other option is below grade at 30'' with a soil backfill or dust clay mix, as mentioned to rods 6' apart and using a cad connection or two acorn clamps . Use a old 6'' sewer and drain pipe from the connection to grade for the test well or inspector.
You want a good ground ! I have seen electrical poles hit with lightning and blow the concrete out from the end of rebar cause that was the only ground point.
mac
The other option is below grade at 30'' with a soil backfill or dust clay mix, as mentioned to rods 6' apart and using a cad connection or two acorn clamps . Use a old 6'' sewer and drain pipe from the connection to grade for the test well or inspector.
You want a good ground ! I have seen electrical poles hit with lightning and blow the concrete out from the end of rebar cause that was the only ground point.
mac
Speedy Petey
Well-known member
A tower site is COMPLETELY unrelated to a residential home. You DO NOT need all that **** and expense.We do several ground rods for tower sites in bed rock all the time . What you need is a SDS 1'' max bit that is 3' and several 24'' extensions. You need ground bed enhancement material or electro ground bed kit that can be purchased from any large electrical outlet or tower supply house like Site pro.
The other option is below grade at 30'' with a soil backfill or dust clay mix, as mentioned to rods 6' apart and using a cad connection or two acorn clamps . Use a old 6'' sewer and drain pipe from the connection to grade for the test well or inspector.
You want a good ground ! I have seen electrical poles hit with lightning and blow the concrete out from the end of rebar cause that was the only ground point.
mac
Ground rods do VERY little in a small home setting. A Ufer (CEE) is definitely the best grounding electrode, and is still all you need if you have one.