250.106 Lightning Protection Systems.

[bhellmer]

250.106 Lightning Protection Systems.
"The lightning protection system ground terminals shall be bonded to the building or structure grounding electrode system."

To comply with 250.106, I typically specify rods to ground either the building or lightning protection system and a ring to ground the other with a bonding jumper between each rod and the ring. Alternatively, each lightning protection ground terminal could be bonded to structural steel.

A colleague has suggested after reading NFPA 780, that this is unnecessary. He insists that we only need a single bonding between a lightning protection conductor and the facility's main grounding bar.

Our debate is about how literally to take 250.106.

Does 250.106 require the direct bonding of each ground terminal or is a single bonding adequate for the entire system?

 

[bphgravity]

It appears your colleague is referring to Section 4.14.5 in the NFPA 780 which allows ONE connection to other building grounded systems.

 

[bhellmer]

I have always practiced compliance with the most stringent applicable code.

I wish 250.106 was the following:
"The lightning protection system shall be bonded to the building or structure grounding electrode system according to NFPA 780."

 

[bphgravity]

I wish 250.106 was the following:
"The lightning protection system shall be bonded to the building or structure grounding electrode system according to NFPA 780."

CMP 5 awaits your public input for the 2020 NEC code cycle...