The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Sprinklered equipment 26-008
by bigpapa
12/02/16 04:24 PM
On Delay Relay with Auto Reset
by Potseal
12/01/16 09:59 AM
Wow, that was close!
by jraef
11/28/16 07:06 PM
Earthquake in New Zeeland
by RODALCO
11/27/16 11:25 PM
Calling all Non-US members!! (Non-US only)
by Tjia1981
11/27/16 06:33 AM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 13
HotLine1 9
Texas_Ranger 8
sparkyinak 7
Trumpy 6
Who's Online
0 registered (), 133 Guests and 5 Spiders online.
Key: Admin, Global Mod, Mod
Page 1 of 3 1 2 3 >
Topic Options
Rate This Topic
#81903 - 09/30/02 07:02 PM Ground Rod Woes Revisited...
sparky66wv Offline
Member

Registered: 11/17/00
Posts: 2339
Loc: West Virginia
A picture is worth 1000 (curse) words...



The above pic shows the consistency of the um, "soil"... for want of a more descriptive word... The groundrod visible is resting upon the back-fill pile.



Shown above, one ground rod will lie in the trench at 30" deep, as far from the 1-1/2" PVC conduit as practical.



The second rod will be in the as yet non-existent trench, which will extend another 15' from the end of the existing one.

How would you tackle this?

Does your PoCo accept Ufers, plates, rings or other electrodes? If not by default, how do you gain acceptance of alternate means?

This is but the first of many possible services I'll do in the general area of these photos, so I'll be tackling this problem many times. Large, powerful, and dangerous machines and methods will also be considered!

[This message has been edited by sparky66wv (edited 09-30-2002).]
_________________________
-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI

Top
2014 / 2011 NEC & Related Books and Study Guides
#81904 - 10/01/02 03:48 PM Re: Ground Rod Woes Revisited...
txsparky Offline
Member

Registered: 05/25/01
Posts: 578
Loc: Magnolia,.Texas U.S.A.
Where I'm at,we have sand or clay or any combination in-between.Haven't had to deal with rock.None of the PoCos I deal with(5 different ones) would ever know to look for a second rod.Can you drive a rod there with a roto-hammer?I asked because I noticed someone was able to auger in the trailer tie down rods(Hmmm.... I wonder....nah)Anyhoo,what are you doing your trenches with now?That trailers gonna need water and sewer;any chance of working something out with the plumbers? I've gotten many a trench dug for a case or two of their favorite beverage
_________________________
Donnie

Top
#81905 - 10/01/02 04:08 PM Re: Ground Rod Woes Revisited...
sparky66wv Offline
Member

Registered: 11/17/00
Posts: 2339
Loc: West Virginia
I've tried a rotary-hammer once and wasn't very impressed. The combination I was using may have had something to do with it. I had better luck with a sledge. The rotary hammer was one of the big bosch's, can't remember the #... SDS Max, I believe. I'd used it to core drill a 2" hole and figured, that since I'd paid the damage waiver on the rental, I'd give driving a rod a shot. (I know, that probably wasn't a cool thing to do...)

It didn't work well.

The only thing that has actually impressed me is a Bosch electric jack hammer. But I ain't liftin' 90 lbs eight feet up! Besides, they're a couple grand I think!

Would a ground plate require a smaller hole, and would it offer less resistance/impedance and be a more effective electrode?

What about Ufers?

Txsparky, No problem on this particular one, the trench was extended and back filled today. Plus this installion will only be here about a year. Since this is a future golf course, (the Greenbrier) I'm trying to plan for better grounding options if/when the time comes and I'm called upon. I'm just trying to explore more options for the not-too-distant future, but I want to really offer electrodes that work.

Am I right to assume that ground rods are practically useless in these soil conditions?

[This message has been edited by sparky66wv (edited 10-01-2002).]
_________________________
-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI

Top
#81906 - 10/01/02 05:24 PM Re: Ground Rod Woes Revisited...
Bjarney Offline
Moderator

Registered: 04/10/02
Posts: 2561
Loc: West-Southern Inner-Northeast ...
Shot from the hip, but any chance a chemical rod/counterpoise would do the job? http://www.lyncole.com/html/Rod.asp#lshaped

Top
#81907 - 10/01/02 05:39 PM Re: Ground Rod Woes Revisited...
Fred Offline
Member

Registered: 04/30/01
Posts: 461
Loc: Straughn, IN 47387
Sparkywv,
I've went to Ufer grounds everywhere in the last 2 years. It took some educating of the local inspectors but it's worth it. It does make the telephone guys mad that they don't have my ground rod to tag on to but that's life. It can be such a crap shoot when driving a rod around here. It always seems like the drains, gas line sleeve or water line ends up in the same corner as the UG service does and it's a gamble to start ramming 8' of anything in the ground there. Not to mention what nature or someone has burried there. I did a new house once and couldn't get anything deeper than 3'. The excavator who dug the foundation later told me he uncovered 6'x10' sections of concrete sidewalk. The building site had once been a dumpsite for the city when they re-did Main Street. On a rural new home job that had been a farm years ago, the excavator dug up a 1947 Plymouth sedan while digging the basement for the new house!
Ufers all the way!

Top
#81908 - 10/01/02 06:09 PM Re: Ground Rod Woes Revisited...
sparky Offline
Member

Registered: 10/18/00
Posts: 5545
to be honest Virgil
i can rarely cut 250.53(G), save for an 'oblique' angle myself.... (puff...puff..pant...)

aw, just throw 'em in the ditch...


 Quote:
What about Ufers?


well, the NEC does not quite come out and say it, but 250.52(A)(3)sounds Uferish ....
it almost sounds as if the 1-7 are in order of preference....

 Quote:
250.50 Grounding Electrode System.
If available on the premises at each building or structure served, each item in 250.52(A)(1) through (A)(6) shall be bonded together to form the grounding electrode system. Where none of these electrodes are available, one or more of the electrodes specified in 250.52(A)(4) through (A)(7) shall be installed and used.


 Quote:
Formal Interpretation 78-4
Reference: Article 250.50
Question: Is it the intent of 250.50 that reinforcing steel, if used in a building footing, must be made available for grounding?
Answer: No.
Issue Edition: 1978
Reference: 250-81
Issue Date: March 1980


right... ever try convincing the concrete dudes? i just did a ufer last month, & was dubbed loco sparky'......

now the poco engineers recognize the efficy , seems the linecrew traditionally look for rods..... i guess you'll need to talk to the poco boss..

sometimes a 250.52(A)(4) "ground ring" is spec'd out by architects. i just don't know how to 'encircle' a structure with only 20' though...

 Quote:
Am I right to assume that ground rods are practically useless in these soil conditions?


comparitively i'd vote yes, useless...

i'm sure there's a Soares ditty about the efficy of 'made' electrodes, i've heard of some who drive excessive depths and/or distances apart to achieve a decent ohmic value.

I also heard the IAEI did a study....



[This message has been edited due to blistered fingers}

[This message has been edited by sparky (edited 10-01-2002).]

Top
#81909 - 10/01/02 06:13 PM Re: Ground Rod Woes Revisited...
HotLine1 Online   content

Member

Registered: 04/03/02
Posts: 6804
Loc: Brick, NJ USA
Hey 66
I have to ask....what the x@#$ is a "ufer"
Some of us boys up here in the "cities" ain't heard of that.

In a serious note; what is a ufer???

John
_________________________
John

Top
#81910 - 10/01/02 06:16 PM Re: Ground Rod Woes Revisited...
sparky Offline
Member

Registered: 10/18/00
Posts: 5545
 Quote:
excavator dug up a 1947 Plymouth


no, no... Fred, put it back....i can make it work..


(7) Other Local Metal Underground Systems or Structures. Other local metal underground systems or structures such as piping systems and underground tanks.

Top
#81911 - 10/01/02 06:18 PM Re: Ground Rod Woes Revisited...
sparky Offline
Member

Registered: 10/18/00
Posts: 5545
read here John

Top
#81912 - 10/01/02 08:12 PM Re: Ground Rod Woes Revisited...
sparky66wv Offline
Member

Registered: 11/17/00
Posts: 2339
Loc: West Virginia
Beej, as a last resort, I've had to make my own L-shaped rods (good 'ol MAP gas!) after hitting limestone or granite. The hammer gets to be like hitting a brick wall with an aluminum baseball bat! Ouch! The sandstone in the pics above is relatively soft in comparison!
I could drive 'em at about 100 strokes per inch, but I'm getting to old for that crap!

I've even been crafty enough to actually dog-leg a rod so that the top of it looks like it's going straight down, just in case the AHJ likes it that way...

John, A Ufer is a Concrete Encased Electrode. I've never used one, but I'm told they are the default and primary grounding means in Oregon (Someone here said that, I think). So a Ufer is, what 20' of copper in atleast 2" of concrete? What size copper? Pipe, Rod or wire?

Fred, shoulda bonded to the Plymouth like Steve is eluding to! Hee hee!



Steve, gimme a minute to read all those links! You da man, BTW! (What you got, like 3100 posts or something?!!? *jealous*)

BRB...
_________________________
-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI

Top
Page 1 of 3 1 2 3 >



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals