Lightning Protection and Building Ground

[Hobbyist]

I was under the impression that a lightning protection system needed to be bonded to the buildings regular grounding system? The lightning protection can have it's own ground rod but you need to find a point that they can be bonded together. If I'm correct what section of NFPA 780 calls this out?

Thanks in advance

 

[Dennis Alwon]

We are electrical contractors so we deal with NFPA 70.

 

[Dennis Alwon]

This is what I see in 780

4.12.1.1

Each down conductor shall terminate to one of the following:

• (1)
  One or more grounding electrodes dedicated to the lightning protection system
• (2)*
  A grounding electrode system of a building, structure, or facility that has multiple grounding electrodes bonded together with a ground ring electrode meeting the requirements of 4.12.4

 

[Dennis Alwon]

If there is an existing service ground rods then it may not meet this criteria

4.12.2.4.1

The ground rods shall extend vertically not less than 10 ft (3 m) into the earth, as illustrated in Figure 4.12.2.4.1.

Figure 4.12.2.4.1 Typical Single Ground Rod Installation.

 

[Hobbyist]

 

[don_resqcapt19]

250.106 Lightning Protection Systems.​

The lightning protection system ground terminals shall be bonded to the building or structure grounding electrode system.