Lightening protectors\Grounding

[rpearson]

I will be installing 2 Marconi lightening protectors for 100pr.outside plant phone feeder(direct bury) next week.Will I be able to ground each end(protectors) to structural steel(perlins,v-bar,I-beams,etc.)?Is there a current governing code or standard per EIA\TIA,NEC for this type of installation?In anycase,I would rather pull a #6 to the nearest TGBB.However,Im installing this in one of the Harley-Davidson powertrain plants and the run will be quit long,and I may have to pull the #6 about 1,000',from the furthest protector to the nearest TGBB.As you can imagine this building is huge.I want to cut a corner in pulling the conductor in,but make it legal.Thanks.

 

[daronwilson]

You want to be looking at the NEC first to make it electrically safe. Good Luck, the grounding section is confusing at best. Secondly if you are interested in standards compliance, the EIA/TIA standards certainly will cover what should be done.

I'm on vacation and have both documents on CD with me, when I sit down to sip coffee I'll browse and see if I can give you any specific direction. Off the top of my head, I think I would drive a ground rod, bond it to the structural steel ("I" beam) and feel like it was well protected against a lighting strike/power hit. However, I'm pretty sure that won't meet code for bonding, and I know it won't be standards compliant.

I'll try and look some of it up.

Good Luck! It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[rpearson]

That would be great!Thanks.

 

[executone]

I have always grounded the protector boxes and the shield of the barried cable to a grounding rod using #6 cable between the two. Put a grounding rod as close to each protector and cable.

Good Luck!!

 

[shipwright]

The shorter the ground wire the better the protection.You can test the ground ohms with an impedence meter.

 

[daronwilson]

I will look, really, just still doing the family participation thing. Basically what I think you want for your protection is a ground rod and short ground wire bonded to the shield as stated above. That will do the protection you should have, and actually if you do not bond this ground to other grounds, you may not have to tackle the whole bondage issue. In a perfect world, ground should be ground. When you go between two buildings, with potenially two different ground potentials, and you tie them together (bonding), you need to do that with a large enough conductor to handle it.

I suppose, if you bonded the shield to the building ground on each side, the shield it self could carry potential current that would be the difference in ground between the buildings. An open ground/neutral in one building could cause a huge amount of current flow on that shield. So it may actually be better to just ground it to a ground rod and not connect to either building.

Still thinking... It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[daronwilson]

Ah never enough time for research. After reviewing things, here is what I would do if I were in that situation (not making it right, mind you). Drive a ground rod where the cable comes up, bond it to the ground block with a #6. Take a #6 from the ground rod to the building steel, and if an electrical panel/service ground were within 50 feet or so, I'd pull another #6 and bond to that ground as well.

Sorry, I just don't have the time right now to quote you chapters from the standards and codes, but I think that is reasonably close.

Good Luck! It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[Bobg1]

Number 1 rule keep it short. If you would have to go 1000'
you might as well not even put it in. If you have to you can even punch a hole through a floor to install a ground rod.