ground a new service box

[Ben Holloway]

ok guys Im a little new at this so dont tear me apart to bad. Im installing new 200 amp service in my garage and Im using a square D all in one service box. Since its going into a building that has been around for 30 years and I dont have any water service out there I only need one ground to the copper rod, My buddy gave me instructions on how do it with 2 grounds but something got lost in translation and Im a little stumped. All I have to do is run the copper wire to the ground/neutral bar and the to the rod right or is there something Im missing?
Like This
http://img235.imageshack.us/img235/7547/box1kz8.jpg (http://imageshack.us)
Maybe This
http://img235.imageshack.us/img235/6717/box2zf9.jpg (http://imageshack.us)


thanks
Ben

[Aces'n'8s]

Every panel comes equipped with a bonding screw. Usually, it looks like a 10-32 screw w/a threaded hole. Look for an offset wire that's flat on one end and has a hole in the other end. It looks like a wavy "S" (about the size of a #8 wire).

Basically, it bonds the nuetral bus to the panel and thereby you only one ground in this case at least a #8 grounding wire, but I'd recommend #6 ground wire.

Hope that helps.

[78bronco460]

Call your local inspector. He'll tell you for sure, but I believe in your location they want two 8 foot rods with a single unspliced grounding electrode conductor connecting them to the service. That's some hard earth in Bend, you'll be beating the hell outta them to drive em in. Here's the Oregon Specialty Code amendments to the NEC on this subject:

"918-305-0160
Amend Article 250 -- Grounding
The following provisions of Article 250 are amended:
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.
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(5) Section 250.52(B) -- Electrodes Not Permitted for Grounding. Insert the following after Section 250.52(B)(2), as follows "(3) In existing electrical installations, when a service change or upgrade occurs, an existing metal underground water pipe shall not be used unless the metal underground water pipe has been verified as suitable for continued use as a grounding electrode. An existing metal underground water pipe shall be bonded to the new grounding electrode system as required by 250.52 and 250.58."

(6) Section 250.56 -- Resistance of Rod, Pipe, and Plate Electrodes. Insert the following at the end of the first sentence: "For permanent installations where the only grounding electrode is a single ground rod, pipe or plate, documented verification of 25 ohms or less shall be provided. Documented verification shall be done by a recognized method, provided by the installer, and made available for the electrical inspector."

The local inspector has the final word, so that's why I suggest calling him and making it easy on yourself.
Good luck.

[Hvy_Chevy]

call the inspector.

use a big hammer drill to punch the rods down with. seen it done a few times that way, worked slick for them.

[Ben Holloway]

I drove the rod already, I just want to make sure I get the box part right, Ill check for that bonded wire, So in that case I should have to ground one bar then right...

Ben

[jdrocks]

is this a subpanel or a new dedicated service?

[Aces'n'8s]

call the inspector.

use a big hammer drill to punch the rods down with. seen it done a few times that way, worked slick for them.

If you use a hammer to pound a grounding rod down, you're setting yourself up for a failed inspection. I'm sure some jurisdiictions are different, but in Memphis, Tn, if an inspector sees a grounding rod that has been hammered flat on its top, he's going to laugh and tell you "Bubbye".

The better way to do it is to use water to loosen the surrounding soil and slowly work the rod into the ground pulling up and then driving down.

I drove the rod already, I just want to make sure I get the box part right, Ill check for that bonded wire, So in that case I should have to ground one bar then right...

Ben

Yes, you should only have to run one ground wire. Sometimes, the bonding wire/screw will even have a little tag on it.

[Ben Holloway]

hehe thats what I did about 60 gallone of hot ass water and 3 hours and I finally got the rod in the ground, thanks for the help

Ben

[Aces'n'8s]

hehe thats what I did about 60 gallone of hot ass water and 3 hours and I finally got the rod in the ground, thanks for the help

Ben

Yeah...sometimes I've hit gravel...sometimes I've had to pull it out and go inboard/onboard of the house wall. Sometimes I've got lucky and it goes in too easy.:D

Looking at your Square D panel, the way you MS Paint'd the neutral lugs, you would be fine attaching your ground to either one. I'm betting there's a bar behind the main buss that attaches both neutral busses to the panel box altogether.

Therefore, the Square D panel might not have the "wavy S" bonding screw/attachment point. I do know that GE Profile, Murray and Seimens usually have those bonding screws.

[Hvy_Chevy]

If you use a hammer to pound a grounding rod down, you're setting yourself up for a failed inspection. I'm sure some jurisdiictions are different, but in Memphis, Tn, if an inspector sees a grounding rod that has been hammered flat on its top, he's going to laugh and tell you "Bubbye".

and how do they know if you cut off the top 1" of that 8' rod?
where did I say hammer? last I checked, a hammer drill is not a "hammer"

[Aces'n'8s]

and how do they know if you cut off the top 1" of that 8' rod?
where did I say hammer? last I checked, a hammer drill is not a "hammer"

You're right...It didn't register that "drill" was in there. So, you've got an 8' rotary hammer bit. Or do you chuck it up in a 1/2"-3/4" rotary hammer?

[Hvy_Chevy]

1/2" rod fits in a 1/2" drill.
I'm sure you can figure out the rest.

[threadkiller]

If you use a hammer to pound a grounding rod down, you're setting yourself up for a failed inspection. I'm sure some jurisdiictions are different, but in Memphis, Tn, if an inspector sees a grounding rod that has been hammered flat on its top, he's going to laugh and tell you "Bubbye".



That's the first I've heard of that. We use hammers and jackhammers to drive ground rods in Nashville and the surrounding counties.

What is the inspector's justification for not allowing hammered ground rods?

[fj40charles]

What is the inspector's justification for not allowing hammered ground rods?

Inspector might think that you cut off the grounding rod.

If this is a subpanel, the neutral and ground should NOT be bonded.

A good way drive the grounding rod into the ground is.. start pounding it in, pull it out and pour some water down the hole. Wait a while and repeat.

[Ben W]

If this is a subpanel, the neutral and ground should NOT be bonded.


Is a subpanel supposed to have its own grounding rod?

[Travis Waldher]

Is a subpanel supposed to have its own grounding rod?

yes.

and he shoule have said, a subpanel must not have the neutral and ground bus bonded.

I'm not sure how they do it in commercial bulidings, maybe they just have to be bonded to a common ground bar system?

[Aces'n'8s]

1/2" rod fits in a 1/2" drill.
I'm sure you can figure out the rest.

Yes it does. If using a rotarty hammer, I ASSumed everyone used a driver bit for the hard jobs...not just chucking it up in an 1/2" drill.

That's the first I've heard of that. We use hammers and jackhammers to drive ground rods in Nashville and the surrounding counties.

What is the inspector's justification for not allowing hammered ground rods?

Jackhammers....jackhammers?:shaking:

Have you ever checked to make sure the ground rod didn't fracture or break entirely? Have those ground rods ever been tested with the proper equipment to check resistence? Did they register <25 ohms?

In the scheme of things, I guess jackhammering ground rods ranks a slightly better that cutting them in half/quarters or trenching them.

But, I'd rather do in a way where I know most of that 8' is INTACT and in the ground.;)

[Ben Holloway]

1/2" rod fits in a 1/2" drill.
I'm sure you can figure out the rest.

Its not a sub-panel, 200amp service requires a 5/8ths rod here so no hammer drill, I got it all hooked up today and ready for the rough in inspection. Hopefully Ill have power in my garage by next week. I bet putting in 200 amp service to power on 30amp plug is gonna raise some eyebrows, I was thinking of buying a bunch of seeding trays and potting soil to see how good of an eye the inspector had:flipoff2:

Ben

[nate379]

All sorts of crazy laws. I've never built something in a place that had inspections.

You get the permit, build what you want and that's it. It if falls down or burns down, your own fault :D

[cnielsen4130]

Inspector might think that you cut off the grounding rod.

If this is a subpanel, the neutral and ground should NOT be bonded.

A good way drive the grounding rod into the ground is.. start pounding it in, pull it out and pour some water down the hole. Wait a while and repeat.

There are stamped markings with a few numbers on the top end of every ground rod, and if the inspector cant see those, he might get worried, we have pretty strict codes here, and i have new been hassled for pounding ground rods with my rotary hammer, or even manually. they DO have a pretty trick ground rod out that is TWO 5/8'' x 4' combined rods that serve the purpose of one 8' that i have seen advertised in electrical magazines. pretty cool when your working around the type of adobe clay soil i have to deal with here. You can also use a eupher ground burried in your concrete as your second ground. If your really new to this stuff, make sure your phasing is correct if your using 3 wire circuits and sharing neutrals. In a service (meter/ main panel) , the neutral bus and ground bus are shared, in a sub panel the neutral and ground bus are seperate. its not code that a sub panel is grounded with its own ground rod, if its grounded from its source with the proper size ground. good luck

[lqCJ5]

If this is a subpanel, the neutral and ground should NOT be bonded.


it's not a sub panel , its got meter clips on top

[Gummi Bear]

and how do they know if you cut off the top 1" of that 8' rod?
where did I say hammer? last I checked, a hammer drill is not a "hammer"


They're looking for the manufacturers stamp, which is near the top.




You don't use a hammer drill, you use a SDS type of drill, with a 'chipping hammer' mode. There is a ground rod driving attatchment that fits right over the top of the rod. No mushroomed head, and it beats the fawk out of swinging a sledge or a T-Post driver.

Water driving is cool, I do it when I can, but often times hit rock.

You can also dig a 8' long trench that is 30"deep, and lay the rod in it and it is perfectly legal.

You can drive the rod at a 45* oblique angle maximum. All 8' must be in contact with the earth.

5/8" is the minimum diameter for a grounding electrode

2 ground rods driven in the earth must be at least 6' apart. They 'leech' out ~30"

3/4" GRC is an approved substitute for a ground rod, should one not be available.

Use #6 to a ground rod

Use a bronze acorn clamp, Al is not acceptable (you can also exothermically weld the wire to the rod)


:D


I had to go to CE yesterday for my license. It was over grounding this year, a nice refresher.

[Gummi Bear]

yes.

and he shoule have said, a subpanel must not have the neutral and ground bus bonded.

I'm not sure how they do it in commercial bulidings, maybe they just have to be bonded to a common ground bar system?

That depends on the municipality.

Some say yes, some say no.

Ask your AHJ(Authority Having Jurisdiction, inspector)