NEC 800-30 a 1
- Thread starter karnold
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- Bremerton, Washington
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Re: NEC 800-30 a 1
Draw a line from the top of the building to the ground. A round ball that could just fit inside the line would define the cone. for more information, Polyphaser has a book "The grounds for lightning and emf protection" plus white papers at their web site.
Draw a line from the top of the building to the ground. A round ball that could just fit inside the line would define the cone. for more information, Polyphaser has a book "The grounds for lightning and emf protection" plus white papers at their web site.
Re: NEC 800-30 a 1
The "cone of protection" extends from the top of the object to the ground in a circle and it starts at an angle of 45 degrees from vertical. Unfortunately, with objects taller than 30 meters, the size of the cone's maximal ground radius will remain fixed at about 30 meters. Of course, this is not perfect, and there are no good scientific studies of the safety of this "cone of protection."
An definition from the Lightning safety institute: CONE OF PROTECTION: A conic space around a vertical lightning rod used to define a region of protection. The cone whose height equals the height of the rod and whose base radius is equal to the rod height. Regarded as an obsolete term.
[ March 21, 2003, 06:48 PM: Message edited by: dereckbc ]
The "cone of protection" extends from the top of the object to the ground in a circle and it starts at an angle of 45 degrees from vertical. Unfortunately, with objects taller than 30 meters, the size of the cone's maximal ground radius will remain fixed at about 30 meters. Of course, this is not perfect, and there are no good scientific studies of the safety of this "cone of protection."
An definition from the Lightning safety institute: CONE OF PROTECTION: A conic space around a vertical lightning rod used to define a region of protection. The cone whose height equals the height of the rod and whose base radius is equal to the rod height. Regarded as an obsolete term.
[ March 21, 2003, 06:48 PM: Message edited by: dereckbc ]
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