Lightning protection requirement
- Thread starter anbm
- Start date
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kwired
Electron manager
- Location
- NE Nebraska
What exactly are you asking about?
There is a difference between surge arrestors installed on the lines to clamp transients (some which may come from lightning events) and a true lightning protection system which is intended to try to eliminate or divert the effects of a direct strike - though the latter is probably not so common for what you are asking about but more common for a building.
There is a difference between surge arrestors installed on the lines to clamp transients (some which may come from lightning events) and a true lightning protection system which is intended to try to eliminate or divert the effects of a direct strike - though the latter is probably not so common for what you are asking about but more common for a building.
drktmplr12
Senior Member
- Location
- South Florida
- Occupation
- Electrical Engineer
As far as i know, there is no NEC requirement for lightning protection of a building or equipment.
Typically MV switches will have lightning arresters to source high frequency currents induced from nearby strikes. You would look for an "LA" on the schematic, where the incoming line is. Or check the shop drawing/as built of the equipment to see if it's specifically identified.
The name of the game in direct strike lightning protection is giving the current a path that doesn't destroy something expensive or important. That said, a lightning arrester wouldn't protect from a direct strike.
One way would be to put an enclosure around the gear and install a UL listed lightning protection system, including grounding counterpoise, on that structure.
Another is to do it is an individual mast/pole with an air terminal at the top and beefy aluminum tied to a low resistance grounding counterpoise.
NFPA 780 provides guidelines of the what and how.
Typically MV switches will have lightning arresters to source high frequency currents induced from nearby strikes. You would look for an "LA" on the schematic, where the incoming line is. Or check the shop drawing/as built of the equipment to see if it's specifically identified.
The name of the game in direct strike lightning protection is giving the current a path that doesn't destroy something expensive or important. That said, a lightning arrester wouldn't protect from a direct strike.
One way would be to put an enclosure around the gear and install a UL listed lightning protection system, including grounding counterpoise, on that structure.
Another is to do it is an individual mast/pole with an air terminal at the top and beefy aluminum tied to a low resistance grounding counterpoise.
NFPA 780 provides guidelines of the what and how.
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