Need help with lightning rods

[sspradling]

Inspected a nice old victorian 3 story today. When I got on the 1-5 year old roof, I saw the lightning rods had been nicely cleaned up, but there was no grounding straps, cables, conductors, nothing. My question is: Would the owners be better off re grounding them, or would they be ok to just be a decorative bauble? I haven't seen that many lightning rod systems except in the country, and they have all been intact, all the way to an electrode in the ground. My gut feeling is that if the rods are up there, there should be a properly installed, complete system. Anyone know of any specs or references? Any first hand advise? Thanks in advance.
Stu

[Jay Moge]

i'm with you there. but i don't have a reverence either. if it's not grounded and is the highest point around, lightning hits it during a rain storm ( the rain giving it an electrical path to the earth.) are they helping or hurting?

[Jeffrey R. Pope]

This may help. . .


250.60 Use of Air Terminals. (Lightning Rods)

Air terminal conductors and driven pipes, rods, or plate electrodes used for grounding air terminals shall not be used in lieu of the grounding electrodes required by 250.50 for grounding wiring systems and equipment. This provision shall not prohibit the required bonding together of grounding electrodes of different systems.

FPN No. 1: See 250.106 for spacing from air terminals.
See 800.40(D), 810.21(J), and 820.40(D) for bonding of electrodes.

800.40(D) Bonding of Electrodes.

A bonding jumper not smaller than 6 AWG copper or equivalent shall be connected between the communications grounding electrode and power grounding electrode system at the building or structure served where separate electrodes are used. Bonding together of all separate electrodes shall be permitted.

[sspradling]

Jeff, thanks for the reference, I didn't know the code name was air terminals. Do you think an incomplete system for these things is cause for calling it out? Who do I defer this to, an electrician? I'd really like to get it right the first time. Again thanks for any help.
Stu

[Gerry Beaumont]

Stuart,

When many of these older Victorians were built they were the tallest things around, and they commonly had Air terminals installed, these days you only tend to see them on Highrises, commercial structures and comunications towers.

Whenever I have seen them I have defered them to a licensed electrician. I would certainly recommend that you note in your report that the Lightening rods were not connected at the time of inspection. Should they be re-connected frankly I don't know

Regards

Gerry

[Jeffrey R. Pope]

Originally Posted by gbeaumont

Whenever I have seen them I have defered them to a licensed electrician. I would certainly recommend that you note in your report that the Lightening rods were not connected at the time of inspection. Should they be re-connected frankly I don't know

What he said. . .

I don't think I've ever seen a lightning rod, other than at the golf course

[sspradling]

If I could figure out the new photo upload for my (previously not too large) images, I would be sharing. Maybe I'll figure it out some day..
Thanks for your help on this topic.
Stu

[jtedesco1]

NFPA 780 Standard for the Installation of Lightning Protection Systems 2004 Edition

Chapter 1 Administration

Chapter 2 Referenced Publications

Chapter 3 Definitions

Chapter 4 Protection for Ordinary Structures

Chapter 5 Protection for Miscellaneous Structures and Special Occupancies

Chapter 6 Protection for Heavy-Duty Stacks

Chapter 7 Protection for Structures Containing Flammable Vapors, Flammable Gases, or Liquids That Can Give Off Flammable Vapors

Chapter 8 Protection for Watercraft

Annex A Explanatory Material

Annex B Principles of Lightning Protection

Annex C Explanation of Bonding Principles

Annex D Inspection and Maintenance of Lightning Protection Systems

Annex E Ground Measurement Techniques

Annex F Protection for Trees

Annex G Protection for Picnic Grounds, Playgrounds, Ball Parks, and Other Open Places

Annex H Protection for Livestock in Fields

Annex I Protection for Parked Aircraft

Annex J(Reserved)

Annex KProtection of Structures Housing Explosive Materials

Annex L Lightning Risk Assessment

Annex M Guide for Personal Safety from Lightning

Annex N Informational References

Formal Interpretation

Index

[Jeffrey R. Pope]

Well that certainly made it clear Joe

I know nothing about lightning rods (and may never have the need). Can you give some insight as to some of the basics?

[jtedesco1]

http://www.nfpa.org/aboutthecodes/Ab...asp?DocNum=780

Preview this document.

I posted this for review: Display the Table of Contents of this document.

My intention was to identify the standard that may have some information to be used for a reference only. See Chapter 3.

NFPA allows a review of all of their codes and that's where this is found, see www.nfpa.org codes and standards.

[Paul W. Abernathy]

The grounding electrode for a lightning protection system cannot be used for the building or structure grounding electrode system as required by 250.50. Figure 250–110

Author’s Comments:
• Where a lightning protection system is installed, it must be bonded to the building or structure grounding electrode (earthing) system [250.106].
• A lightning protection system installed in accordance with NFPA 780, Standard for the Installation of Lightning Protection Systems, is intended to protect the building structure from lightning damage. It isn’t intended to protect the electrical wiring or equipment within the structure from lightning damage. To protect from high-voltage transients, proper transient voltage surge-protection devices must be installed in accordance with Articles 280 and 285.

• GROUNDING ELECTRODE CONDUCTOR. Grounding metal parts of the electrical installation to earth is intended to reduce voltage on the metal parts from lightning so as to prevent fires from surface arcing (side-flashes) within the building or structure [250.4(A)(2)]. In addition, high-voltage distribution systems (typically electric utility wiring) are grounded to the earth to help limit high voltage on system windings from lightning, unintentional contact with higher-voltage lines, or line surges [250.4(A)(1)].

[bkelly1]

In laymens terms. lol ... it should be bonded to something or lighting will find its own path. Ground or remove, that is my opionon. Have installed a dozen of these and they have to be grounded. We installed them on the many water and waste water plants I have wired, as well as all steeples on the churches I did. Back in the day.

[rwand1]

They are not functional. No ground does it still draw lightening?
I think lightening does not always hit the hightest point, it may go for transformer/pole, tree, ground.

Are you suppose to ground metal roofs?

[bkelly1]

That is just my thoughts. There are companys now that are making plastic rods for this reason. My sister looked into them while building her house. The state inspector sais if they were copper, they would be grouded. Period. But maybe that is just him ?

[bkelly1]

http://www.furse.com/elp/howtolp.htm