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Is it true that a concrete foundation pile is acceptable for use as lightning down conductor, but that the leakage current could crack the concrete? What does code say about this?

Hi Salim,

Thank you for your question regarding lighting protections systems and concrete pile foundations, it is our pleasure to help.

If you read the NFPA 780 (US Lightning Standard) it would appear to not allow the use of pile foundations for use in lightning protection, however it is commonly done within the United States.  The IEC 62305 allows it as long as the impedance from end to end of the pile is below 0.2 ohms and there are welding overlaps in the rebar.  Here are some links with information you may want to review discussing this topic.

https://www.esgroundingsolutions.com/about-electrical-grounding/lightning-protection-systems-nfpa-780.php

https://www.esgroundingsolutions.com/blog/755/how-do-you-support-a-lightning-protection-down-leads-run-in-a-plenum-ceiling

https://www.esgroundingsolutions.com/blog/516/do-i-need-down-conductors-to-be-bonded-to-the-re-bar-in-concrete-column

https://www.esgroundingsolutions.com/blog/290/is-it-safe-to-use-structural-steel-as-a-down-conductor-for-a-lightning-protection-system-at-a-school

But you are correct in being concerned about using the building you are trying to protect as part of the Lightning Protection System (LPS).  It is the official position of E&S Grounding Solutions to discourage the use of building structures as part of any Lightning Protection System (LPS).  Not only do you risk damage to the concrete, but you also risk injury to personnel and equipment.

Feel free to call us at 310-318-7151 California time should you have any further questions, someone will be glad to speak with you about your project free of charge.

Best regards,

The Engineering Team at E&S Grounding Solutions

 

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