lighting rod bonding

[MissLiz]

I have a home that had lightning rod installed on the roof but I quess because the installer could not get to the ground rods or the panels the system was never bonded. the question I have is there is no way to get to the panels due to the construction of brick and block drive ways etc.. I had a lightning strike and burned up generator circuit board which is only 3 ft from the lightning grounding electrode, can I run a bond wire from the electrode to metal frame
of generator or would this create a more dangerous condition?

 

[weressl]

I have a home that had lightning rod installed on the roof but I quess because the installer could not get to the ground rods or the panels the system was never bonded. the question I have is there is no way to get to the panels due to the construction of brick and block drive ways etc.. I had a lightning strike and burned up generator circuit board which is only 3 ft from the lightning grounding electrode, can I run a bond wire from the electrode to metal frame
of generator or would this create a more dangerous condition?

You should install a 'downcomer' from the lightning rod to the ground rod in the most direct vertical run as possible with bending radii not less than 8". Lightning protection material is also somewhat different than regular conductors for better performance. (Eg. braided conductor instead of just stranded.)

 

[BAHTAH]

Lightning Protection

Lightning Protection

I have a home that had lightning rod installed on the roof but I quess because the installer could not get to the ground rods or the panels the system was never bonded. the question I have is there is no way to get to the panels due to the construction of brick and block drive ways etc.. I had a lightning strike and burned up generator circuit board which is only 3 ft from the lightning grounding electrode, can I run a bond wire from the electrode to metal frame
of generator or would this create a more dangerous condition?

Lightning protection systems need to be properly designed and installed. As mentioned the materials are not just what you usually find at the local wholesale house. Typically
one lightning point will not protect an entire roof structure. I would suggest you contact a major lightning protection company as they will have an installation guide for
materials and layout. IEEE has a publication you can get on-line. I always used Thompson Lightning Protection INC., they had an excellent guide. Their phone number is
1 (800) 777-1230. You can also find them on-line.

 

[dereckbc]

I have a home that had lightning rod installed on the roof but I quess because the installer could not get to the ground rods or the panels the system was never bonded. the question I have is there is no way to get to the panels due to the construction of brick and block drive ways etc.. I had a lightning strike and burned up generator circuit board which is only 3 ft from the lightning grounding electrode, can I run a bond wire from the electrode to metal frame
of generator or would this create a more dangerous condition?

OK I am going to take a different approach, and you will probable not like my comment with an Attitude Adjustment upside the head with a 2 x 4. Take the lightning rod and everything associated with it off the building and trash it. It will only cause you problems as you have already experienced. Most likely will be more incidents down the road.

OK now that you are hot under the collar allow me to explain. What you have up does not comply with any known lightning protection system or electrical codes. It is actually making you a target looking to destroy something like a generator control board.

Even a single Air Terminal system requires two down conductors going to a COMMON Ground Electrode System like a ground rods or even a ground ring system. It must also be bonded to the AC service ground electrode. There is a very good reason which you have discovered why 250.58 exist which basically states all ground electrodes Shall Be bonded together to form a single common Ground Electrode System. Immediately following is 250.60 for Air Terminals which tells you the air Terminal electrode Shall Be Bonded to the building GES.

What is happening is when lightning strike the Air Terminal and enters the dirt a Step Rise Potential difference develops along the surface of the dirt placing the Air Terminal electrode at one potential and you AC electrode at a much higher magnitude potential. In other words up to 10's of thousands of volts difference. That potential is looking for a path to equalize and it found one right through your genny.

So from my point of view you have two options:

1. Remove the Air Terminal and all associated equipment which will take the Bulls Eye Target off your building.
2. Fix it and make it right bringing it up to code and acceptable Lightning Protection Practices which exceed NEC code. FWIW get a copy of NFPA 780 aka Lightning Protection Bible.