Lightning Protection-Proximity to Roof-mounted equipment

[PaulHartley]

I'm looking in NFPA 780 for rules on the proximity of roof-mounted electrical equipment to lightning rods (air terminals).

Does anyone know where this type of rule may be found?

Thank you,

 

[cdafd]

from 2014 edition

not sure if this is what you are looking for


4.7.11* Chimneys, Vents, and Other Objects on Roofs Not in a Zone of Protection. Strike termination devices shall be required on all objects not located within a zone of protection, including metal objects having a metal thickness of less than 3/16 in. (4.8 mm) except as permitted in 4.7.11.1 through 4.7.11.4.


4.7.11.1 Metal objects with a metal thickness of 3/16 in. (4.8 mm) or more and not located in a zone of protection shall require connection to the lightning protection system using a main-size lightning conductor and a main-size connector in accordance with the following:


(1)
It has a surface contact area of not less than 3 in.2 (1940 mm2) or a minimum of 1 1/2 in. (38 mm) of contact along the axis of a round surface.


(2)
Two or more paths to ground are provided, located as is required for strike termination devices.





4.7.11.2* Required strike termination devices shall be installed on objects, as shown in Figure 4.7.11.2, so that the distance from a strike termination device to an outside corner or the distance perpendicular to an outside edge is not greater than 2 ft (0.6 m).

















View Large






FIGURE 4.7.11.2


Print



Air Terminals on a Chimney.








4.7.11.3 Where only one strike termination device is required on an object, at least one main-size conductor shall connect the strike termination device to a main conductor at the location where the object meets the roof surface and provides two or more paths to ground from that location in accordance with Section 4.9 and 4.9.2.



4.7.11.4 Objects on roofs that are less than 10 in. (254 mm) above the surface of the roof shall not require strike termination devices unless they are located within 3 ft (0.9 m) of the ridge or roof edge.




4.7.12 Metal Roof Top Units. Strike termination devices shall be required in accordance with 4.7.12.1 through 4.7.12.3.2 on all roof top mechanical units with continuous metal housings less than 3/16 in. (4.8 mm) thick, such as air-conditioning/heating units, metal air intake/exhaust housings, and cooling towers, that are not located in a zone of protection.


4.7.12.1 Air terminals shall be installed in accordance with 4.7.2 through 4.7.5.



4.7.12.2 The air terminals shall be mounted on bases having a minimum contact area of 3 in.2 (1940 mm2), each secured to bare metal of the housing or mounted by drilling and tapping to the unit's frame in accordance with 4.19.3.2 and 4.19.3.3.



4.7.12.3 At least two main-size conductors shall be installed to connect the unit to the lightning protection system.


4.7.12.3.1 The connection shall be made to bare metal at the base or lower edges of the unit using main-size lightning conductors and bonding devices that have a surface contact area of not less than 3 in.2 (1940 mm2) and shall provide two or more paths to ground, as is required for strike termination devices.



4.7.12.3.2 The two main bonding plates shall be located as far apart as practicable at the base or lower edges of the unit's electrically continuous metal housing and connected to the lightning protection system.

 

[PaulHartley]

Thank you CDAFD,
This was slightly helpful, but what I'm not finding are rules on how close a metal device (in this case a Solar Panel) that is not bonded to the Light. PRot. System can be to
an air terminal (strike termination device).

Thanks again

PH

 

[cdafd]

from the 2014 edition


""(3)
Locating strike termination devices (including air terminals, masts, and overhead ground wires) adjacent to the solar panels in such a manner as to place the solar panels in a zone of protection as defined in Section 4.8 ""



12.2.2 Protection shall be provided by one or more of the following methods:


(1)
Direct mounting of strike termination devices to the solar panel


(2)
Direct mounting of strike termination devices to the solar panel framing


(3)
Locating strike termination devices (including air terminals, masts, and overhead ground wires) adjacent to the solar panels in such a manner as to place the solar panels in a zone of protection as defined in Section 4.8









4.8 Zones of Protection. The geometry of the structure shall determine the zone of protection.


4.8.1 One or more of the following methods shall be used to determine the overall zone of protection:


(1)Air terminal placements, as described in Section 4.7

(2)The angle method, as described in 4.8.2

(3)The rolling sphere method, as described in 4.8.3

 

[PaulHartley]

Thank you for your input...I appreciate it.
Paul