What’s inside a lightning arrestor?

What is inside one of those things? The folks over at Northstreetlabs have set out to answer just that question. You’ve seen these things before, and if you’re uneducated on the subject like myself, you just assumed they were there to stop a possible connection from a power line to the pole/building to which it is attached. Apparently that is part of their purpose. When presented with lightning, however, they turn to conductors allowing the lightning to pass to ground.

You can see their teardown in video form, as well as an explanation of how exactly they work on their site.


  1. fartface says:

    And they explode quite violently when hit with a mazzive strike.

    I was 1200 feet away from a substation when it was struck with a really fat lightning bolt. Most everything looked like it exploded, but later it was found that all the Suppressors like this blew up and then the safety breakers released too slow causing extra arcs.

    http://youtu.be/SBzRmWeC6Ds This is what it looks like when those safetys fail, and those happened on 4 of them after the lightning strike.

  2. Rob Lister says:

    I am smarter for having read and seen that. I thought they were strictly for insulating the power line from the pole. And I always wondered what was inside. Now I know!

  3. jwk says:

    Fascinating, thanks for posting. I’ve also seen the results of what happens when they blow up and arc, but never knew what was inside.

  4. truthspew says:

    Wow – that vid above is interesting. Back about ten years ago a transformer down the street from me got blown off a pole due to a lightning strike. But the lines sat there are arced away for a good 2 minutes until the power went out.

  5. Timbob says:

    At the utility I work for, lightning arrestors are used inside the substation (in addition to spark gaps) to protect substation equipment like circuit breakers and transformers.

    The lightning arrestors are the grey insulators to the left and right of the picture.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


Get every new post delivered to your Inbox.

Join 96,387 other followers