Ground rod at Exterior Light Pole

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Gategator37

Senior Member
If a lightning strike can generate over 200,000 volts what is the point of a ground rod that can only dissipate about 6,000 volts?
 
480sparky

480sparky

Senior Member
Location
Iowegia
jumper said:
As i said, in post #4, different specs, but not code AFAIK.

Am I wrong?
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No, you just have different EEs. They're pretty much SOP around here. I try to save the customer money be giving them the option of not installing them, but they're bound & determined it's gonna save 'em millions of dollars.
 
G

Gategator37

Senior Member
I do a lot of design reviews and never commented on the issue because I know it can't do any harm, I just don't see the upside too it. I see it as wasting money, especially when there are several pole lights
 
Dennis Alwon

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
With ground rods a lot has to do with soil conditions etc. Obviously the lower the ohms the better the rod. Theoretically it is suppose to help with lightning strikes, surges, etc and it may help some in some areas but generally they are a waste because of the high resistance. Heck the pole is probably a better rod then the rod. :)
 
jxofaltrds

jxofaltrds

Inspector Mike®
Location
Mike P. Columbus Ohio
Occupation
ESI, PI, RBO
480sparky said:
Bonded (Bonding). Connected to establish electrical continuity and conductivity.

How do you bond something that really has poor conductivity?
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I understand bonding/grounding.

It does not say excellent conductivity just conductivity.

Just look at some of the bonding jumpers in exhibit 250.29.
 
mcclary's electrical

mcclary's electrical

Senior Member
Location
VA
A ground rod driven on average here is about 80 ohms to ground.


There's no way it is helping much compared to an already far superior ground of a huge chunk of concrete and rebar in touch with the earth.

But, keep in mind lighting takes all available paths, who's to say it doesn't help "a liitle tiny, tiny, bit"


It would be hard to prove it.
 
R

Ragin Cajun

Senior Member
Location
Upstate S.C.
Where I used to work they had an incident at a ball park where the hot leg came in contact with the pole but didn't trip the breaker and a kid got hurt. Since then they made VERY sure that the pole was solidly grounded. Lawyers and all that. Now I simply bond the pole to the rebar.

I have seen in Fla. where there are lightning rods, etc. at the top of tall poles.

RC
 
mcclary's electrical

mcclary's electrical

Senior Member
Location
VA
Ragin Cajun said:
Where I used to work they had an incident at a ball park where the hot leg came in contact with the pole but didn't trip the breaker and a kid got hurt. Since then they made VERY sure that the pole was solidly grounded. Lawyers and all that. Now I simply bond the pole to the rebar.

I have seen in Fla. where there are lightning rods, etc. at the top of tall poles.

RC
Click to expand...

an extra ground rod does not facilitate the tripping of the OCPD
 
G

Gategator37

Senior Member
The u-bolts that connect to the rebar in the pole base supplies a better ground than the actual ground rod is what I can recall.
 
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