air terminal installation

[Todd Dorer]

Following is the information on the location for the subject question:

50' steel pole (installed via anchor bolts in a concrete foundation) with a closed circuit television camera attached approximately 30" below the top of the pole.
3' copper, pointed air terminal attached to the top of the pole by threaded connection into the top of the pole.
No down wire for path to earth.

Question:
Does this air terminal provide any protection for the structure or attached devices? Or does it simply extend the height of the pole by the length of the air terminal.

 

[markstg]

Per NFPA 780 Standard for the Installation of Lightning Protection Systems, section 5.2 seems to cover this. It reads:

5.2 Masts, Spires, Flagpoles.
5.2.1 These slender structures shall require one strike termination
device, down conductor, and ground terminal.
5.2.2 Electrically continuous metal structures shall require
only bonding to ground terminals.


It seems 5.2.2 allows the pole to be the strike termination device and down conductor. The base of the pole needs to be bonded to the ground rod/terminal/grid. So adding an air terminal would only extend the height of the pole as you say.

 

[Cavie]

Following is the information on the location for the subject question:

50' steel pole (installed via anchor bolts in a concrete foundation) with a closed circuit television camera attached approximately 30" below the top of the pole.
3' copper, pointed air terminal attached to the top of the pole by threaded connection into the top of the pole.
No down wire for path to earth.

Question:
Does this air terminal provide any protection for the structure or attached devices? Or does it simply extend the height of the pole by the length of the air terminal.

They make a 3" wide copper band/strip to lead down to the ground rods. See your lightning protection supplier. There should be a #6 bare ground imbeaded in the pole for grounding that eliminates the copper strip.