COMMUNITY FORUM

tbone20tnt

06:07PM | 11/24/02
Member Since: 11/07/02
9 lifetime posts
Bvelectrical
I have read several books that say the top of the ground rod needs to be 1 foot below the ground. Mine sticks up about 3 inches. Now that I think about it I have never seen a residents that didn't have a ground rod sticking a few inches above the the ground. Can someone please clear this up for me?

electricmanscott

01:07AM | 11/25/02
Member Since: 11/05/01
101 lifetime posts
National electrical code requires ground rod end to be below the surface unless protected from physical damage. No particular depth required just below the surface.

rpxlpx

02:27AM | 11/25/02
Member Since: 03/13/00
1678 lifetime posts
If a ground rod is close to a brick wall, is it "protected from physical damage" ?

JonathanGennick

02:39AM | 11/25/02
Member Since: 11/02/02
72 lifetime posts
Why a ground rod? I seem to recall the water pipe being used as a ground back when I grew up. What's the reason to not use water pipes today?

Tom O

09:21AM | 11/25/02
Member Since: 09/17/02
487 lifetime posts
Jonathan,

In an acronym "PVC". Also, you still have to use the metal water line if it extends at least 10 feet underground.

The minimum length of a ground rod is 8 feet. This accounts for the majority of rods sold.

Rod & pipe electrodes are required to have at least 8 feet in contact with the soil. Therefore, the rod, at the very least, must be driven flush with grade and any 8 foot rod that protrudes above grade is not in compliance with the NEC.


gs99

11:19AM | 11/27/02
Member Since: 11/18/02
30 lifetime posts
NEC 250.53(G) "The upper end of the electrode shall be flush with or below ground level ..." and Exhibit 250.23.
Exhibit 250.9 seems to indicate a connection made above ground level.

The comment in section 250.53(G)says "Ground clamps installed above ground must be protected where subject to physical damage." In this case, the electrode itself must be longer than 8 ft.?
What kind of protection and damage? Any examples?


Tom O

04:35AM | 11/28/02
Member Since: 09/17/02
487 lifetime posts
GS99,

If the connection is above grade, the rod must be longer that 8 feet.

Damage means what it says, in many instances from a lawnmower.

Protection- Sleeve it with Schedule 80 pvc pipe or IMC or RMC. Other methods may be fine, but it would be up to the AHJ.


gs99

03:13AM | 11/29/02
Member Since: 11/18/02
30 lifetime posts
Tom O,

Is there any concern about "damage" due to weather (ie. freezing/thawing cycles) degrading the clamp connection over years?


Tom O

04:36AM | 11/29/02
Member Since: 09/17/02
487 lifetime posts
gs99,

Never heard of any concerns dealing with freeze & thaw as regards ground rod conections.

Keep in mind that if this is a ground rod sticking up, chances are it is already a violation. Concerns about damage can be alleviated by pounding the rod flush or below grade.

You seem to be interested in grounding. "Soares Book On Grounding" is highly regarded in the trade. Plenty of diagrams & pictures. Well worth the $$$.

Tom

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