Ground Rod size

Merry Christmas
Status
Not open for further replies.
W

wireday

Senior Member
Location
New England
Occupation
Master electrician
Are we permitted to at anytime use a ground rod less than 8 feet in length? Particularly in broad band coax installations?Also if a Rod is less than 5/8 in diameter but listed are we allowed to use that? Thanks
 
I know a few codes back,2011maybe that the phone company may have used 5 foot ground rods.I've got a CATV company using them saying there OK.So thats why Im asking.
 
I am not aware of anywhere in the code that allows a ground rod less than 8'. Th code specifically states that a rod less than 5/8" if listed is compliant.

250.52(A)(5) Rod and Pipe Electrodes. Rod and pipe electrodes
shall not be less than 2.44 m (8 ft) in length and shall
consist of the following materials.
(a) Grounding electrodes of pipe or conduit shall not
be smaller than metric designator 21 (trade size 3⁄4) and,
where of steel, shall have the outer surface galvanized or
otherwise metal-coated for corrosion protection.
(b) Rod-type grounding electrodes of stainless steel
and copper or zinc coated steel shall be at least 15.87 mm
(5⁄8 in.) in diameter, unless listed.
Click to expand...
 
I believe yo u will find in 800.100(B) where there is no other electrode available, a communication system grounding electrode is allowed to be 5 ft in length and 1/2" diameter.
The same us true for Network Broadband systems as noted in 830.106
 
Just old.. :) I knew I had seen the 5ft ones on Cable installs,,, The ones I saw were likely illegal as there were other premises electrodes available but at one time it may have been permissible even if other means were available... will take some research to find out
 
We have buried ground rods,our plan is to make them available by removing the dirt over them.The CATV company is going to come back and bond to our ground system.They have the 5 foot ground rod already installed.Are we required to change it to 8 foot? Thanks
 
This is a older building,then a generator was installed with a main/ATS outside.Then it was decided to instal the lateral broadband.But yes there was no provision left.
 
Can you actually use a rod for broadband systems or must it be tied to the building GES?
 
When CATV company got on sight there was no IBT,or exposed GES for them. It looks like they resorted to 800.100(B)(3)(2) which allows them to use a 5 foot rod. Now that it is going to be bonded to our GES 800.100(D), does that mean we should follow 250.50? Im trying to understand if we can keep the 5 foot electrode or change it to 8 foot if required.
 
If they did away with the ground rod,looking at it from another view are they allowed to get GES from our buildings steel beams.there box is mounted to our siding, would they have to bond within 5 feet from entering?
 
Last edited:
wireday said:
If they did away with the ground rod,looking at it from another view are they allowed to get GES from our buildings steel beams.there box is mounted to our siding, would they have to bond within 5 feet from entering?
Click to expand...
250.68(C)(2) says...
The metal structural frame of a building shall be permitted
to be used as a conductor to interconnect electrodes
that are part of the grounding electrode system,
or as a grounding electrode conductor.
Click to expand...
 
Thank you Smart, do you also think if we just bond there 5 foot electrode to our ground electrode with a minimun #6 that would take care of it? thanks

When CATV company got on sight there was no IBT,or exposed GES for them. It looks like they resorted to 800.100(B)(3)(2) which allows them to use a 5 foot rod. Now that it is going to be bonded to our GES 800.100(D), does that mean we should follow 250.50? Im trying to understand if we can keep the 5 foot electrode or change it to 8 foot if required.
 
wireday said:
Thank you Smart, do you also think if we just bond there 5 foot electrode to our ground electrode with a minimun #6 that would take care of it? thanks

When CATV company got on sight there was no IBT,or exposed GES for them. It looks like they resorted to 800.100(B)(3)(2) which allows them to use a 5 foot rod. Now that it is going to be bonded to our GES 800.100(D), does that mean we should follow 250.50? Im trying to understand if we can keep the 5 foot electrode or change it to 8 foot if required.
Click to expand...
A 5' ground rod is only compliant when there is no GES present. To retain it after compliant bonding is a violation.
 
So you are saying I should do away with the ground rod? It would seem we could change it to a 8 foot ground rod and make it part of our GES for the CATV to ground to.
 
wireday said:
So you are saying I should do away with the ground rod? It would seem we could change it to a 8 foot ground rod and make it part of our GES for the CATV to ground to.
Click to expand...
The 5' rod, yes... do away with it. Changing it to a 8' ground rod is compliant.
 
Smart $ said:
A 5' ground rod is only compliant when there is no GES present. To retain it after compliant bonding is a violation.
Click to expand...
Why is it a violation as long as there is other compliant electrodes? Isn't it just a supplemental electrode at that point even though it don't qualify as a stand alone electrode? Sort of like driving a rod at a machine in a plant because the manufacturer wants one, as long as it also has bond to the building electrical grounding system, if that manufacturer only specified a 5 foot rod, so what, you still have other compliant grounding electrodes for the premises wiring as well as a mostly useless piece of metal driven in the earth near the machine.
 
Status
Not open for further replies.
Top