Need help with lightning rods

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.

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?


[/size][/FONT]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.[size=2][FONT=Times-Bold]




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.


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 :wink:



What he said. . .

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

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.

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

Well that certainly made it clear Joe :roll:

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

Preview this document.

I posted this for review: [Display the Table of Contents of this document.](http://javascript<b></b>:openWindow( ‘/catalog/toc/780-04-toc.html’))

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 codes and standards.

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)].

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.

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?

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 ?

The older lightening rod systems, at least in my area used braided copper cable. Don’t see many anymore. Does anyone know why it would be braided? Something to do with disappating heat?

Lightening rods and glass bulbs, some where hand painted are collectors items. Most farm houses had white glass balls. I believe decorative not functional.

You still use the braided on many properly installed commercial applications. I beleive you are right , it is for disippating heat.

This is because if the skin effect. High frequency current tends to flow down the skin of the wire. Fine stranded, braided wire has more skin.

That copper would be quite expensive. I hate to think how much of it is burried on the farm so to speak… Good explanations thanks!

We wired an airport about five years ago. 10ft, 3/4 ground rods everywhere. Lighting wire in the ground for MILES! The most expensive thing on the job was the lightning protection. MAny areas had "10ft triangles " with the ground rods also.