Lightning Art

[Chad Fabry]

Schedule 40, 3-inch steel pipe. The overhead stranded triplex was completely blasted away save for a 2 foot piece dangling from the pole.

This building is a hundred feet from mine.

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[Marc]

Electrical service riser?

Marc

[Chad Fabry]

Yes, service riser

[Marc]

Being so close to the utility lines with nothing but the utility super lag fuse on the xformer primary to stop it, the power is available to vaporize considerable metal, shoot drops of molten metal out and cause serious flash-burns on anyone who happens to be around.

The utility has instrumentation at the power plant that records these short circuit spikes. More than once, at a forge plant where I once worked, they would call and ask if everything was ok when our 1,000 amp, 480 V buss duct would short out.

Marc

[Tom Raymond]

So how does it feel to win the lottery?

[mjr6550]

I am looking at the photos on my phone. It appears that the strike was near the ground.

I like how the current melted the pipe and left the coupling intact.

Quite a few years ago my chimney was hit. Bricks flew about 150 feet.

[Rob Amaral]

Sound made: "frrzzzzintISHLAPP"

(Courtesy Don Martin Mad Magazine/1960's)

[Marc]

I am looking at the photos on my phone. It appears that the strike was near the ground.

I like how the current melted the pipe and left the coupling intact.

Quite a few years ago my chimney was hit. Bricks flew about 150 feet.

So this was a lightning strike?

Marc

[Chad Fabry]

The thread title is "Lightning Art" Is that too subtle?

[Les]

I was thinking it was a quote from a movie. "lightning, Art!"

[Marc]

The thread title is "Lightning Art" Is that too subtle?

That sort of damage is typical of a short between an ungrounded SE conductor and the metallic conduit. It isn't typical of a lightning strike.

Marc

[Chad Fabry]

The thread title is "Lightning Art" Is that too subtle?

That sort of damage is typical of a short between an ungrounded SE conductor and the metallic conduit. It isn't typical of a lightning strike.

Marc

The top of the mast was completely gone and, as I stated earlier, also missing/ vaporized was about 50 feet of stranded triplex. It wasn't on the ground, it was gone. I assume the triplex was hit. I can imagine a scenario where that occurred and subsequently the insulation on the SE conductors was compromised inside the riser.

Edit: Notice that both sides of the riser are gone.

[Marc]

A lightning bolt is characterized by extreme voltages which can translate into extreme energies developed if the resistance of the path is high. That's why brick explodes when hit: It is not a good conductor. Triplex and the steel conduit are both excellent conductors and 'grease' the path for lightning currents to safely reach the earth where it dissipates. That's why lightning rods, braided cable and ground rods of lightning systems remain undamaged by even the greatest of strikes: their conductivity is excellent.

I can see how a lightning strike may have initiated the short in the triplex but only the ensuing fault current in the triplex itself could have vaporized that much metal.

Marc