lightning protection

[David C. Macy]

House has a lighting protection system and one of the connections is at the gas meter.

I would think that is not a real good place to direct lighting to.

What is the proper way to direct the lighting to ground for this type of system?

What is the correct terminology for this type of lightning protection.

Would it be a good recommendation to have the lighting system removed as I believe the electrical has been updated and ground rod(s) have been added.

[iniquette]

David, I agree with you , gas meter doesn't seem like a real good spot for this to be directed to. I have these on my home, and they are directed to their own grounding rod. I am not sure how deep this rod goes into the ground though. I have one rod on each end of the house. Around here they just call them lightning rods and grounding rods. Not sure if that is the true technical term or just a common name for them, never gave it much thought.

[Michael Roberson]

I agree, and the wire shouldn't be near the gas meter at all.

[Jeffrey R. Pope]

What/where was the primary grounding electrode?

The gas piping is required in most jurisdictions to be bonded to the GE, but cannot be used as the grounding electrode.

250.106 Lightning Protection Systems. The lightning protection system ground terminals shall be bonded to the

building or structure grounding electrode system.

[David C. Macy]

Originally Posted by jpope

What/where was the primary grounding electrode?

The gas piping is required in most jurisdictions to be bonded to the GE, but cannot be used as the grounding electrode.

250.106 Lightning Protection Systems. The lightning protection system ground terminals shall be bonded to the

building or structure grounding electrode system.

The GEC was at the exterior, ground rod(s), recently installed.
The pictured system is a separate lightning system and one of the ground terminals was the gas meter.

I was setting up a radon and was getting a jump on the inspection, going back tomorrow.

[Corlick Mark]

Originally Posted by dmacy

House has a lighting protection system and one of the connections is at the gas meter.

I would think that is not a real good place to direct lighting to.

What is the proper way to direct the lighting to ground for this type of system?

What is the correct terminology for this type of lightning protection.

Would it be a good recommendation to have the lighting system removed as I believe the electrical has been updated and ground rod(s) have been added.

I am really surprised to hear that the lightning protection system is directed toward the gas meter. I suggest you to change it. In general cases, the gas meters are grounded with salt which have very low resistance. This is the same process that is followed in substation.

[Jeffrey R. Jonas]

This is an old thread, but I'll comment anyway...

These systems are typically very old (in my area approx 75+ years) and look just like the one shown, and should be on it's own ground rod. When multiple conductors are used, each usually has it's own grounding rod. From what I see in the pic's, I would bet that the grounding was moved when the metal siding was installed. This is very common, and a mistake made by siding installers that have no clue. Also, was the metal siding bonded to the system? It should be.

[KEVIN WOOD]

I think someone got the bonding mixed up with what is required for GEC.
I agree with Jeffrey P.

[Paul W. Abernathy]

Hello All,

The reason they probably connected to the gas piping is due to the proximity of of it to the system. If lightning were to strike the lightning terminal strikes and then make it's path to ground and for some reason it had an issue at that location then lightning (current) would arc off the lighting protection conductors over to the gas line since it is in contact with the earth thus providing a path and a difference of potential for that lighting. Bonding them together provides an equal potential between both of them which would lessen the chance of an arc situation and possible damage to the gas line. Seems the opposite but those are the hard facts.

While it is not typical in the example shown I would be ok with the bonding. The real risk is the potential between these two grounded points. The danger of a arc due to the potential difference is too great to not bond them together at this point. In a new NFPA780 compliant installation the layout would be much different.

[Jeffrey R. Jonas]

Thanks Paul.

[George P. Wells, CMI]

Originally Posted by pabernathy

Hello All,

While it is not typical in the example shown I would be ok with the bonding. The real risk is the potential between these two grounded points. The danger of a arc due to the potential difference is too great to not bond them together at this point. In a new NFPA780 compliant installation the layout would be much different.

I agree with Paul's comments. A lightning protection system is a Faraday shield. An ideal lightning protection system would be a Faraday cage. Very small differences in impedance in parallel paths can cause extremely large differences in potential with a lightning strike. Putting a lightning protection system on its own ground rod could have disastrous consequences. It is much safer to terminate a lighting lead to a gas line than to a ground rod.

[George P. Wells, CMI]

Originally Posted by iniquette

David, I agree with you , gas meter doesn't seem like a real good spot for this to be directed to. I have these on my home, and they are directed to their own grounding rod. I am not sure how deep this rod goes into the ground though. I have one rod on each end of the house. Around here they just call them lightning rods and grounding rods. Not sure if that is the true technical term or just a common name for them, never gave it much thought.

Ian, if your lighting protection is isolated from your house's electrical system, you could have an extremely dangerous installation. You would be much safer not to have the lightning protection at all than to have it isolated from your electrical power distribution.