Generator Grounding

[NhcoastalJ]

I have a free standing Onan Cummins generator that I have installed in a shed approximately 35 feet from my house.
Can I use my well casing as the generator ground?
Do I risk destroying my well pump?
It is grounded back to the house panel but they want two ground points also my water comes in through a plastic pipe.

The ground is extremely rocky and I'm having major difficulty getting the grounding rod in any considerable depth.

Thanks!

 

[jonyyuma]

Try using water with the rod and jog it up and down quickly. Or borrow an impact hammer and drive it with ease? Use a fence post driver to pound it in. Lots of forceful ways??Bury it horizonal...

 

[moeh1]

They sell an adapter to go in an hammer drill for driving ground rods. I've never used it, but they are supposed to work great.

 

[RadarTech]

Check out the local tool rentals... A rotary hammer will really be the way to go...
I used one and put 15 feet of ground rod down in minutes is clay.. And 10 feet in rocky dirt in 20 minutes..... With a couple of heat breaks on the hammer....

 

[MF1652]

The suggestion to bury the rod horizontally won't work in NH because of our winters. It has to be vertical to get below the frost line at 5'. Otherwise once the ground freezes you no longer have an effective ground source. You just have an insulated ground rod serving no purpose.

Are you hitting ledge? Would it be possible to move the ground rod to a less rocky area?. Then you could just run a burried copper line to the ground rod.

My buddy who is a commercial electrician just chucks the ground rods into a rotary hammer and drives it into the ground but that wont sink it into ledge if that is your problem.

 

[hr3]

I have a free standing Onan Cummins generator that I have installed in a shed approximately 35 feet from my house.
Can I use my well casing as the generator ground?
Do I risk destroying my well pump?
It is grounded back to the house panel but they want two ground points also my water comes in through a plastic pipe.

The ground is extremely rocky and I'm having major difficulty getting the grounding rod in any considerable depth.

Thanks!

NEC says you do NOT ground a generator other than the ground going back to the service ground...

 

[jonyyuma]

The suggestion to bury the rod horizontally won't work in NH because of our winters. It has to be vertical to get below the frost line at 5'. Otherwise once the ground freezes you no longer have an effective ground source. You just have an insulated ground rod serving no purpose.

Are you hitting ledge? Would it be possible to move the ground rod to a less rocky area?. Then you could just run a burried copper line to the ground rod.

My buddy who is a commercial electrician just chucks the ground rods into a rotary hammer and drives it into the ground but that wont sink it into ledge if that is your problem.

I have used the big Hilti hammers to sink them over 50 feet around here. We have the meter to take a reading for it. The steel rods screw together..

 

[Clyde]

Nhcoastal - I live in sand country and two groundrods driven 6' apart as required by state law wouldn't budge the ohn meter one iota when reading resistance across the two rods. I left the rods in to pass inspection and after that pulled them out and ran #2 copper to the well casing. A bit expensive but I ran a rather circuitous route to the house and all of my grounds tie into that copper. Have no fear with your well pump as it is also grounded and lightning is only looking for the fastest route to ground it can find. Your pump is somewhat isolated because of the water around it and the steel casing and water makes that the "perfect" ground supply. Don't shortchange yourself on the ground. Go for the best ground you have and you'll thank yourself many times over. Without moisture in the sand and rock - you have nothing! Even the power companies admit they don't have decent grounding available to them in certain areas so it is up to you to protect yourself.

Best of luck to you and you are going in the right direction in my book - Clyde

 

[Rock knocker]

NEC says you do NOT ground a generator other than the ground going back to the service ground...

I think the issue becomes the fact that it is a permanent standby, installed in a separate outbuilding. In such a case, I believe the NEC would require a ground at the panel in the detached building

 

[hr3]

I think the issue becomes the fact that it is a permanent standby, installed in a separate outbuilding. In such a case, I believe the NEC would require a ground at the panel in the detached building

Read this... Generator Groundig

 

[Rock knocker]

You are missing the point. I think that the inspector is saying that a ground rod is not needed because of the generator, but that a ground rod is needed because it is a seperate building.

 

[techman]

Also don't confuse grounding the generator frame with grounding/bonding the neutral leg.

paul

 

[Rock knocker]

Also don't confuse grounding the generator frame with grounding/bonding the neutral legl

Which can only happen in one place

 

[hr3]

Man you guys ,,, A great quote here would be " If I can't convince you I'll at least confuse you".. The poor OP wanted to know about grounding a non portable generator,,, Not about grounding an out building,,or grounding and bonding of the neurtal ,,, "In one place only ??? didn't get that part..."

 

[Rock knocker]

Man you guys ,,, A great quote here would be " If I can't convince you I'll at least confuse you".. The poor OP wanted to know about grounding a non portable generator,,, Not about grounding an out building,,or grounding and bonding of the neurtal

You brought up the fact that the NEC did not require the genny to be grounded except at the service panel. I pointed out the probable reason the inspector was requiring another ground, which in fact had nothing to do with the gen set.

"In one place only ??? didn't get that part..."

Really. Wow, that speaks volumes

 

[hr3]

I read to OP's question several times,, There was no inspector.. He asked a simple question..

 

[Rock knocker]

There was no inspector...

Or was there

I but they want two ground points also my water comes in through a plastic pipe!

And you were the one who brought up the NEC. So either the manufacturer wants two grounds, or a inspector does

 

[NhcoastalJ]

To try and clarify.

The actual connection from the Gen head to my house panel is a 4-wire 3AWG copper line and I am using all 4 wires including the ground and neutral wire. (I tried using a 3-wire but that was not to code) I use an interlock switch on my house panel as to not back feed.
In my installation manual for my Gen they call for an additional ground that gets connected to my Gen's grounding point on the frame. I did consult with the code inspector but never had him actually come out and inspect anything and it's been over 2 years since my consultation. Because my shed is up on blocks it is not considered a permanent structure and does not need its own ground. (I do not expect any surprise visits at this point)


So it looks like one person is saying gen ground to well casing is okay to do and everyone else wants me to rent a hammer drill and pound the rod into the ground.
I don't think I have ledge in that area but I do have a ton of rocks. :-(

The question was more about can I ground to a well casing and not blow my water pump not how many grounds I need. Just googling I come up with mixed results online.

 

[TCJatko]

I'm certainly not an expert, but to me the well casing seems like an ideal ground. After all, it probably goes into the ground 30 or 40 feet. I don't think it would possibly harm your pump.

 

[dmccarty]

...


So it looks like one person is saying gen ground to well casing is okay to do and everyone else wants me to rent a hammer drill and pound the rod into the ground.
I don't think I have ledge in that area but I do have a ton of rocks. :-(

The question was more about can I ground to a well casing and not blow my water pump not how many grounds I need. Just googling I come up with mixed results online.

I followed the directions that came with the genset and put in a ground rod next to our out building. The soil at our place is mostly a bit of dirt that spaces out the rocks. What passes for "soil" is clay. I was able to pound in the ground rod with a sledge hammer without much problem.

Later,
Dan