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I have a building which regularly experiences nearby lightning strikes. The backup diesel generator is located 10 meters away from the building. Can induced currents from the EMP be reduced within the wires connecting the building to the generator, if they were made to run through a grounded metal pipe? The pipe will run above ground.

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    \$\begingroup\$ I think the EMP is also induced into the ground. Once my home was struck by EMP, the first strike opened the main circuit breaker, the next blinked all the high efficiency lights in the house, even with switches and circuit breakers open. \$\endgroup\$ – Optionparty Feb 23 '15 at 7:42
  • \$\begingroup\$ Not sure you can do anything useful, there's a narrow margin between "close enough to cause trouble" and "so close, nothing can save you". What is the symptom of strikes you are trying to prevent? \$\endgroup\$ – John U Feb 23 '15 at 11:28
  • \$\begingroup\$ @JohnU, the symptom manifests itself in the form of a dead generator control panel. However, there is no noticeable damage to the electronics. The panel is within the building and connected by external wiring to the genset. \$\endgroup\$ – Vasco V. Feb 23 '15 at 12:01
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    \$\begingroup\$ What is "dead" then - is it some sort of cutoff (RCD / fuse) in the panel, control electronics blown, circuit shutdown, exploded... there could be anything in a "control panel" depending on the generator. \$\endgroup\$ – John U Feb 23 '15 at 13:12
  • \$\begingroup\$ This may not be EMP so much as a step voltage increase of the ground itself. When the local ground becomes a few thousand volts for a microsecond, most attempts to engineer around that become frustrated. But that's not a near strike, that's usually a direct hit or a power line laying nearby. \$\endgroup\$ – Sean Boddy Feb 23 '15 at 17:27
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Strictly speaking, in regards to your original post, yes - grounded metallic piping will act as a Faraday cage and can shield wiring and electronics from EMP. To be useful, the whole system must be encased, which may be practical or not. Likely, a conduit could be run directly from the generator to the control panel/annunciator.

Watch out for other signal paths, though. Generators having wiring harnesses that would be impractical to encase, and may need shielded wiring.

As an aside, EMP damage has been assumed here, and may not actually be the case. I still urge that you have the board closely analyzed. Having to replace the board anyway, you might be able to get one with better isolation that isn't susceptible to the kind of failure the original board suffered.

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