When Lightening Strikes an Automated Home

August, 2014

I live in an area that sometimes gets strong thunderstorms.  It’s a relatively flat area and I live on top of a small hill making my house a prime target for lightening strikes.  Over the course of the past few years, the house has been hit directly by lightening at least once, and has several near misses.  I’d like to share my experiences on the impacts of these lightening strikes on my automated home.  In fact, lightening has been the single largest cause of damage to my home automation system over the years.

Aside from the typical, expected impacts from power disruption (brown-outs or black-outs), The most common impacts of near miss lightening strike include:

  • False readings on magnetic sensors at the time of the strike
  • Wiping the memory of some Insteon switches (which means they don’t function properly)

In these instances, the fix for correcting the Insteon switch is to do a factory reset and re-program the switches.  The only switches I have set up with memory settings are those on a 3-way switch configuration.  Resetting them does not take long, but it’s a bit annoying to have to keep resetting them.

When the lightening causes false readings on the magnetic sensors, the house kind of “freaks out” and triggers multiple audio feedback sounds in rapid succession which scares the kids.  I’ve made some attempts to have the home automation system automatically identify and suppress the false data readings on the magnetic sensors, but still have work to do on this.

In one rare case, about 6 years ago, a direct lightening strike caused significant damage to my home automation components including:

  • 1 24-port Ethernet switch not working
  • 1 Russound Source Central Control/Amplifiers not working, and 3 connected wall switches not working
  • 1 external security camera not working
  • 1 Digital Video Recorder (DVR) (used to record the security cameras) not working
  • 2 Measurement Computing Digital IO USB devices (used connect the IO sensors in the house) not working
  • 1 Measurement Computing Temperature USB device (used to connect the temp sensors in the house) not working
  • 2 car presence infrared sensors not working
  • 2 Televisions not working
  • Several AC electrical fuses were popped

This direct lightening strike, while devastating, could have been worse.  It appears the network switch absorbed the surge and prevented other devices on the wired network from being impacted.  Also, the DVR absorbed the surge and prevented other cameras from being impacted.  The Measurement Computing devices absorbed the spike and prevented the home automation servers from being impacted.  Finally, it appears the UPS battery backups connected to all the home automation equipment absorbed the surge and, surprisingly, continued to function normally.

Since the direct strike incident, I’ve taken extra steps to reduce the severity of a direct strike if/when it happens again:

  • Added surge suppression power strips on all major electronics in the house and unplug them when unused for an extended duration
  • Upgraded the Measurement Computing devices to the USB-1024HLS model.  The “H” stands for “High Current” and can handle an electrical surge better.
  • Added fuses to some sensors like the 2 car presence infrared sensors
  • Installed a surge suppressor for the CCTV coax lines
  • Added small 4-port network distribution switches throughout the house

Note:  The AC power strips with surge protection that I purchased included RJ45 ports for connecting network circuits.  Unfortunately, this prevented the NIC from connecting at 1Gbps (the max I could get was 100Mbps) which was frustrating.  So, Instead, I bought small 4-port 1Gbps switches that could serve the same purpose without sacrificing network bandwidth.

Since making these changes, I’m happy to report that I’ve not experienced any additional damage/loss due to lightening.  I feel the added cost for these additional safeguards have been well worth the investment.  Routine monitoring and maintenance seems to keep things running well.

I do have a series of soil moisture sensors buried throughout the yard that I reference when decision to run the irrigation system.  When building this system, I was especially concerned with lightening strikes, so I used some optical isolation relays to protect the circuitry inside the house.  I suppose they’re working well since I’ve never had an issue with this system related to lightening storms.  I guess no news is good news in this case.


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