How do I connect ground rods to my panel ground bus bar?

[bobinyelm]

I have completed wiring my shop, but need to connect the ground bus bar to my 2 8ft ground rods.

I am running the #6 solid, uninsulated wire from the ground bus (isolated neutral) to the ground rods, by running the wire out of the box through a 1/2" cable clamp, but from here I need to exit the building (a pole building with metal skin) to the ground rods immediately below and outside of the breaker panel.

Do I just drill a hole in the metal and run the solid copper through it (with a dab of silicon caulk to prevent moisture and insect intrusion), or do I have to use some sort of anti-abrasion grommet so the steel skin cannot damage the copper wire?

Once outside I plan to run the wire through a ground clamp on rod #1, and thence to termination at rod #2. I left about 8" of the 8ft rods (8ft apart and 8" from the building's slab) exposed for easy connections via the bronze clamps

If I run the ground wire out high-up, then down, can I tie-wrap it to the 1 1/2" PVC conduit that leads from the LP down into the trench, or does it need to be fastened to the building with some special code-acceptable attachments?

I'd ask the inspector assigned to me, but his motto is, "I am here to inspect, and not to instruct." It's obvious he would prefer lay people be made to hire professionals who need little or no supervision (Though I found several violations on my brand new, professionally wired new home built/inspected just a year ago, so even pros make mistakes.), but for the $3k savings on my shop I am more than willing to do the research and appreciate the advice kindly offered here, and am appreciative for it.

Thanks,
Bob

 

[wyliesdiesels]

Are u saying that u connected the GEC(grounding electrode conductor) to the isolated neutral bar?

u can run the GEC through a hole in the metal siding or bring it out of the LB.

Rods are suppose to be pounded flush.

Make sure wire is not subject to damage.

Did u run a 4-wire feeder?

 

[bobinyelm]

Are u saying that u connected the GEC(grounding electrode conductor) to the isolated neutral bar?

No, I meant to say the neutral is not bonded to ground, and is isolated, so the ground wire (GEC) is only connected to one ground bus bar (The ground bus bar on the other side makes ground through the panel box frame I guess). Do I need to connect the two ground bus bars together with a copper jumper (I'll have some #6 bare left if I do)

The two neutral bus bars are bonded to each other with a very heavy (#4 maybe?) removable jumper that came already hooked up inside the box.

u can run the GEC through a hole in the metal siding or bring it out of the LB.
OK, so I can run the ground wire in the same conduit holding the feed cable, then perhaps drill a small hole at the bottom of the LB and route the wire outside the vertical conduit to the ground rods (maybe attached to the conduit using tie-wraps/zip-ties)?.

Rods are suppose to be pounded flush.
OK, after I attach the wires to the rods, I will pound the tops of the rods flush so the clamps are an inch or two underground so all you will see are wires coming out of the ground, and no grounding rod then. On second thought, maybe I'll leave the clamps above ground so the inspector can see they are properly attached, then pound them the last 2" while he looks on?

Make sure wire is not subject to damage.
Other than keeping it close to the building, not sure how to do that unless I put it inside a small conduit itself. How "not subject to damage" does it have to be?

Did u run a 4-wire feeder?
Yes, I used 2/2/4/6 MHFC per the inspector's approval (I couldn't locate 2/2/2/4 of the proper type-it was all URD and the inspector said non-fire rated URD cannot go into a building even if it is inside conduit and totally inside the breaker panel. Everyone here seems to use 2/2/4/6 for 90a service to a detached building. Even Platt Electric, the "big" electrical supply house only had this stuff saying they had never even seen 2/2/2/4. The inspector said that the only time one needs the same gauge for the neutral is for 3 phase.

Last question (I forgot to ask above):

On the supply end inside my main panel for the house (in the garage), I hooked up the ground wire, the neutral wire, and installed the 90a feed breaker, and cut to length and stripped the two hot wires, but have not attached them to the breaker terminals since I did not want to take the chance someone might close the breaker and supply power to the shop panel* since all of the various circuits are exposed outside of their boxes for the initial, or rough-in, inspection.

I left the cover off the main panel, naturally, since the two feeders for the shop ate bent outward so they cannot accidentally contact anything.

Is this how most inspectors expect to see when they arrive?

*All of the breakers in the shop panel are also open, but that box is completely wired (or will be when I attach the ground I asked about). Cover is naturally not attached on that one either.

Thanks-

 

[zmaxmotorsports]

Is it a sub or a main panel with its own main and meter?

 

[dw1]

Bob, usually the inspector will want power on for his final inspection, it has to be on to check GFI's. I would not drill a hole in your feed LB fitting (you can stub a 1/2" pvc LB out and a short piece of pvc pipe if you want), or you can run the ground wire by itself, you can drill a hole down low and then caulk or foam as you said, and as wylie said, make sure it is protected ect (from a weedeater ect) run the ground wire in one continuous piece, loop it through your first ground rod clamp and then at least 6' between rods. I would go ahead and connect the feed wires to the breaker in your house, put the cover on, if the inspector wants to look inside, he can take the cover off.

 

[bobinyelm]

Is it a sub or a main panel with its own main and meter?

The detached shop is a sub panel fed through the 90a breaker in the main panel as detailed in the post thence in underground conduit via 2/2/4/ MHF to the sub panel I was asking about for the grounding conductor.

Sorry if I was confusing.

 

[bobinyelm]

Bob, usually the inspector will want power on for his final inspection, it has to be on to check GFI's. I would not drill a hole in your feed LB fitting (cant do that around here), run the ground wire by itself, you can drill a hole down low and then caulk or foam as you said, and as wylie said, make sure it is protected ect (from a weedeater ect) the ground wire needs to be one continuous piece, loop it through your first ground rod clamp and then at least 6' between rods.

The last time I did this many year's back, I had 2 inspections-

The first inspection was just the trench w/ conduit and cable, panels, and all rough in wiring to all boxes to get the OK before I was allowed to sheet rock and cover up the in-wall wiring, or obscure view inside all of the boxes /with covers or receptacles, so I assumed this first would be that type of inspection so didn't want to take the chance of making anything hot.

The second was a final after sheet rock w/ everything hot and operational.

I have had no inspections on this job to date.

 

[dw1]

The last time I did this many year's back, I had 2 inspections-

The first inspection was just the trench w/ conduit and cable, panels, and all rough in wiring to all boxes to get the OK before I was allowed to sheet rock and cover up the in-wall wiring, or obscure view inside all of the boxes /with covers or receptacles, so I assumed this first would be that type of inspection so didn't want to take the chance of making anything hot.

The second was a final after sheet rock w/ everything hot and operational.

I have had no inspections on this job to date.

OK, I thought you were getting a final inspection, carry on!!

 

[bobinyelm]

OK, I thought you were getting a final inspection, carry on!!

Let me ask this then-

Does it sound that what I have done and reported thus far sounds proper for the first inspection?

Hopefully everything I did is acceptable, of course.

I'll add a thumbnail of my shop panel to this later for any suggestions, but it's late to make huge changes there at this point, of course.

 

[zmaxmotorsports]

The detached shop is a sub panel fed through the 90a breaker in the main panel as detailed in the post thence in underground conduit via 2/2/4/ MHF to the sub panel I was asking about for the grounding conductor.

Sorry if I was confusing.

That what I was wondering,if it was a main with a seperate meter I would connect it through the lug inside meter socket to the ground rods.

 

[bobinyelm]

That what I was wondering,if it was a main with a seperate meter I would connect it through the lug inside meter socket to the ground rods.

Thanks, yes I have LOTS of grounds.

My electric use meter is at the pole on the street (2 ground rods), my main panel 125 feet away at my garage has rods (connected to rebar) in the foundation walls connected to my main panel lug, and my shop will have 2 ground rods.

Thankfully, where I live we have sandy loam and no rocks to make inserting the rods difficult.

 

[dw1]

Let me ask this then-

Does it sound that what I have done and reported thus far sounds proper for the first inspection? Yes, I didn't realize that you were covering the walls inside your barn, so you will need a rough in and final Inspection

Hopefully everything I did is acceptable, of course.

I'll add a thumbnail of my shop panel to this later for any suggestions, but it's late to make huge changes there at this point, of course.

By feeding your barn from the panel in your house, you can get by with one inspection, that is with everything surface mounted in the barn (not covered up) that's why I said in above post about power being on to check GFI operation. You did it correctly with two inspections, since walls/wiring will be covered.

 

[bobinyelm]

By feeding your barn from the panel in your house, you can get by with one inspection, that is with everything surface mounted in the barn (not covered up) that's why I said in above post about power being on to check GFI operation. You did it correctly with two inspections, since walls/wiring will be covered.

Yes, part of the building (a 3 room office/waiting room, walls and ceiling occupying one "bay") will be insulated and sheet rocked, while the remainder (4 service bays) is out in the open and not insulated beside the blanket installed under the sheet metal siding/roof.

Do I have to leave all of the receptacle boxes in the shop area open so the inspector can examine all of the splices/ground connections, or can one install the receptacles/switches and covers on that area and leave the boxes in the area to be insulated/covered open?

I wasn't sure if the inspector would actually want to drag and climb ladders to inspect the overhead boxes for ceiling lighting and other purposes. I have about 45 or so boxes above 8ft that serve lights and "T" down to receptacle boxes at the 4ft level.

Thanks for the clarification!

 

[Cmreschke]

Let me ask a question? Is the lb that you want to come out of metal or plastic. If metal you cannot drill and go through the lb. Plastic you can.

 

[mm08822]

Passing a conductor thru a drilled hole in any lb is not permitted. I would exit the bottom of the panel with rx con and go thru the metal wall as low as i could near the conduit with another rx con instead of a bushing. Pass the conductor thru the wall and cable tie to pvc (on building side) until it got into earth. Then connect to the ground rods. Rtv the rx con in wall. Use Uv resistant ties.

Pound rod a few inches below ground. They need full contact with soil. Leave a few shovels of soil out from around rods so inspector can see conductor, clamps, rods.

 

[Cmreschke]

Drilling out a pvc lb is fine, it is done quite frequently and imo not truly a violation. In some instances drilling an lb is recommended, think weep hole. Clearly not in this situation but still ok. Drilling a metal lb and running a ground thru it is however highly illegal. You would have to choke the geound and that can't be done through an lb.

 

[Cr0ck1]

My shop


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