Automation system hit by lightning

[kurtmccaslin]

Recently my detached garage was hit by lightning.   Here was the damage:
 
In the garage:
1 Omni Pro expander module
1 network switch
2 garage door openers
1 motion detector
2 electric window operators
2 UPB wall switches
1 solar panel monitoring system
 
In the house:
2 keypads
1 network switch
1 water circulating pump
1 Amazon Fire TV
 
I have lightning rods installed on the house and separate garage.

I have a whole house surge protector installed on each of 3 sub panels.  Those seemed to work because the lightning did not travel from the garage to the house on the power line.   However, it did hit the house through the data wiring on the Omni Pro, and on my wired ethernet.    It also seems that I got a jolt through the water system as the water circulating pump was the only damaged item in the house which was not on a low voltage line.
 
I have secondary surge protectors on my automation panels, but not on the garage door openers or on the water pump.
 
There is a cat 6 cable running 140 feet from the house to the garage.   Shielded burial grade wire in conduit.   The shield is not grounded, but there is a ditek surge supressor on both ends.   I know that the shield should be grounded but just have not gotten around to it.   The network switch at both ends of this wire was fried.   
 
There is an unshielded 1 pair data cable from the Omni pro in the house to the expansion boards in the garage.  There is a ditek surge supressor on both ends grounded to the building ground on both ends.   I lost one expansion board (out of 4) and 2 keypads (out of 4) on my data network.   Strange, but the keypad in the garage still works.
 
There is a shielded cat 6 cable from garage to the house.   This is my DSL and phone line.    This cable is not grounded and does not have a surge protector on it.   Nothing was damaged on this line.
 
I have a ground wire running from the Omni Pro to the expander module, and it is tied to the house ground on both ends.
 
Here are my thoughts:
 
- I will upgrade my network to fiber between the house and garage.   I was planning to do this but now it has a higher priority.
- I will put surge protectors on the garage door openers and on my water circulating pump.
- I plan to replace all of the Ditek surge protectors because they failed to protect the system.  (but may have mitigated the damage?)  
- I plan to earth ground my shielded cables at the house end only.
- I will earth ground the Omni panels at the house end only.   (cutting the earth ground at the garage)
 
The only earth ground that is available to my panel is the building ground.   The building ground is a Ufer ground buried in my slab, but it is about 12 feet from my panel via the 12 ga wire to the panel.   
 
Any other ideas on how to protect against this kind of damage?    My house is on a hill, so this could very well happen again.
 
 

 

[RAL]

No lightning protection system (lightning rods) and surge protectors are going to be able to protect your equipment from a direct or close-by lightning strike.  There's just way too much energy to be handled by relatively puny surge protection devices.
 
SPDs are designed to protect equipment from everyday power surges or relatively distant lightning strikes.  The lightning rods will provide a "safe" path to ground for the lightning, which might otherwise pass through the building materials and start a fire and/or cause other damage.

 

[Del91574]

With a good enough hit, no matter what the protection installed is, there's usually going to be damage.
 
The question is whether or not the path to ground was shorter than the protected side of the surge connected devices. Secondarily, the shield on a cable should not be connected to EG on both ends...that's creating an antenna. Same if you extend an EG conductor too far. You also need to look at the clamping voltage that the suppressors have. Too high and you'll damage components before it shunts to ground.

Without knowing the entire details, it sounds like the nature of your install created some of the potential between the grounds and conductors, and when there's a difference in potential, that's voltage and what causes the damage.
 
You can set the systems to be "islands" and protected, but rules of thumb to isolate them need to be followed. Enough transient voltage can be found in any strike or event, but the key is to get it to clamp to ground before the damage, which sometimes still isn't possible. I've pulled cameras that were charred out of service with everything done right from a supression standpoint.

 

[pete_c]

Here have had two (?) hits of lightning (in the last 13 years).
 
1 - one damaged the irrigation controllers (both got zapped).  Nothing else got zapped including the Digi Edgeports that were serially connected nor the solenoids on the manifold.
 
2 - damaged the outdoor HVAC condenser.  Shorted out the 220VAC, fused it, melted the freon lines and started a small fire.  The 220VAC back feed electric to the the fuse panel kicking most of the fuses off plus took out a majority of the Insteon switches.  The contactor and stuff there all melted and fused together.
 
I did add a surge protector for the HVAC unit outside plus I have a commercial one inside (with monitoring circuits).
 
Grounding inside is to ingress water pipes and outside grounding is adjacent to a stake (antennas, lighting arrestors et al).  It is just these two that I am using today.  (satellite, anything coming from the roof, et al is there).
 
In the old house with probably bad grounding I would hear the alarm panel reset itself during a storm with much lightning.
 
Never did lose the programming on it way back (1980's-1990's)

 

[westom]

Any other ideas on how to protect against this kind of damage?    My house is on a hill, so this could very well happen again.

 
Protectors are installed to protect from  destructive surges including direct lightning strikes.  Protectors that do not claim  such protection are wasted money - are for protection from  surges already made irrelevant by protection inside appliances.
 
But no protector does protection.  Apparently you missed THE most important aspect of surge protection.  
 
For example, best protection for TV cable is a hardwire low impedance (ie less than 10 feet) from that cable to single point earth ground. Cable needs no protector to have best protection.
 
Telephone cannot be earthed directly.  So your telco installs a 'whole house' protector (NID) where their wires meet yours.  This protector does not do protection. It connects to earth ground.  That telco 'installed for free' is only doing what the cable's hardwire does better.  Make a low impedance connection to earth.
 
This applies to everything.  Otherwise effective lightning protection does not exist.  Even every 'whole house' protector in each subpanel must make a low impedance (ie hardwire has no sharp bends) connection to that structures single point earth ground.  Not just any earth ground.  The earth ground must be specific, dedicated, and upgraded to both meet and exceed electrical code requirements.
 
No earth ground means no effective protection.  Since so many are sold mythical (near zero) plug-in protectors that have no earth ground, then many just *know* nothing can protect from lightning.  Protection from direct lightning strikes is so  routine that damage is considered a human mistake.  Now start looking for where that mistake was made.
 
If the Ditek protector (at each end) does not make a low impedance (ie hardwire has no splices) connection to single point ground, then it is not doing any protection.  If structures are separated, then each must have its own single point ground.  And any wire inside every incoming cable must connect low impedance (ie less than 10 feet) to that ground.  Either directly (ie cable TV, satellite dish) or via a protector (ie telephone, AC electric, ethernet).
 
An investigation to locate a human mistake always begins with the single point earth ground. Because damage from direct lightning strikes means a human made mistakes or did not learn what was well understood even 100 years ago.
 
Every protection layer is defined only by what  absorbs hundreds of thousands of joules.  That is never a protector.  That is earth ground.  Earth ground for a house is the 'secondary' protection layer.  Also inspect your 'primary' protection layer.  Pictures after the expression "open vertical grounds" are relevant in:
http://www.fpl-fraud.com/
Demonstrated is what to inspect in your 'primary' protection layer.  Every layer of protection is only defined by an earth ground.  And not by any additional plug-in protectors that have no earth ground.  A protector is only as effective as its earth ground.  A term 'low impedance' is also critical.

 

[ecborgoyn]

Protectors are installed to protect from  destructive surges including direct lightning strikes. 

 
I'm sorry to disagree, but even the best SPD/TVSS device isn't going to shunt a direct (or even very close) lightning strike.  Even a low impedance ground could vaporize.  A lightning strike is on the order of 10**9 joules of energy...  SPD's can shunt some amount of energy, perhaps enough for the induced currents from a close strike.  It could depend  on what you are calling 'direct'.  But I don't want to get folks hopes up too high and think that the best SPD's with the best ground path are perfect.

 

[dementeddigital]

The ARRL published some interesting articles about lightning protection for amateur radio, and many of the principles apply here.  It sounds like you've done a lot already.  You might want to bond your water line to earth ground at your main panel too, as it sounds like there was a large potential across the water pipes and your pump's electrical ground. 
 
Here are the ARRL articles:
 
Part1
Part2
Part3

 

[westom]

I'm sorry to disagree, but even the best SPD/TVSS device isn't going to shunt a direct (or even very close) lightning strike.  Even a low impedance ground could vaporize. 

 
Reasons based in emotion are why so many have damage even if using plug-in protectors; that do not claim to protect from destructive surges.  Electronics atop the Empire State Building suffer about 23 direct strike annually without damage. Some techniques used to protect homes were pioneered in munitions dumps - so that direct lightning strikes need not cause explosions.  Telco COs suffer about 100 surges with each thunderstorm.  How often is your town without phone service for four days after each thunderstorm while they replace that $millions computer?  Never?  Because direct strikes without damage is routine when SPD/TVSS/VPR/arrestor/MOV/suppressor/GDT/avalanche diode/etc are installed using concepts well understood even 100 years ago.
 
But again, since many used ineffective (plug-in) protectors and suffered damage, then many just knew nothing can protect from lightning.  They would blame the protector rather than damage due to ignorance.  Protection has been routine since first demonstrated by Franklin in 1752.  Amazing how Franklin's ground conductor also did not vaporize.   "Even a low impedance ground could vaporize" when one knows without first learning facts.
 
One must learn numbers long before making any conclusions.  For example an 18 AWG (lamp cord) wire can conduct something less than a 60,000 amp surge. That number directly from the QST articles that describe how surge protection from direct lightning without damage is done.
 
Since lightning (typically 20,000 amps) must not cause damage, then we use a wire that is four times thicker (ie 6 AWG). 
 
So many professional contradict what was only an emotional belief.  For example:
 

Well I assert, from personal and broadcast experience spanning 30 years, that you can design a system that will handle *direct lightning strikes* on a routine basis. It takes some planning and careful layout, but it's not hard, nor is it overly expensive. At WXIA-TV, my other job, we take direct lightning strikes nearly every time there's a thunderstorm. Our downtime from such strikes is almost non-existant.  The last time we went down from a strike, it was due to a strike on the power company's lines knocking *them* out, ...
Since my disasterous strike, I've been campaigning vigorously to educate amateurs that you *can* avoid damage from direct strikes.  The belief that there's no protection from direct strike damage is *myth*. ...
The keys to effective lightning protection are surprisingly simple, and surprisingly less than obvious. Of course you *must* have a single point ground system that eliminates all ground loops. And you must present a low *impedance* path for the energy to go. That's most generally a low *inductance* path rather than just a low ohm DC path.

 
Many who did not learn these concepts will emotionally deny what was a well understood fact even 100 years ago.  Protection from a direct lightning strike is so routine that damage is considered a human's mistake.

 

[westom]

I'm sorry to disagree, but even the best SPD/TVSS device isn't going to shunt a direct (or even very close) lightning strike.  Even a low impedance ground could vaporize. 

 
Reasons based in emotion are why so many have damage even if using plug-in protectors; that do not claim to protect from destructive surges.  Electronics atop the Empire State Building suffer about 23 direct strike annually without damage. Some techniques used to protect homes were pioneered in munitions dumps - so that direct lightning strikes need not cause explosions.  Telco COs suffer about 100 surges with each thunderstorm.  How often is your town without phone service for four days after each thunderstorm while they replace that $millions computer?  Never?  Because direct strikes without damage is routine when SPD/TVSS/VPR/arrestor/MOV/suppressor/GDT/avalanche diode/etc are installed using concepts well understood even 100 years ago.
 
But again, since many used ineffective (plug-in) protectors and suffered damage, then many just knew nothing can protect from lightning.  They would blame the protector rather than damage due to ignorance.  Protection has been routine since first demonstrated by Franklin in 1752.  Amazing how Franklin's ground conductor also did not vaporize.   "Even a low impedance ground could vaporize" when one knows without first learning facts.
 
One must learn numbers long before making any conclusions.  For example an 18 AWG (lamp cord) wire can conduct up a 60,000 amp surge.  Since lightning is typically 20,000 amps, then a wire that is four times thicker (ie 6 AWG) connects direct lightning strikes harmlessly to earth.
 
So many professionals contradict what was only an emotional belief.  For example:

Well I assert, from personal and broadcast experience spanning 30 years, that you can design a system that will handle *direct lightning strikes* on a routine basis. It takes some planning and careful layout, but it's not hard, nor is it overly expensive. At WXIA-TV, my other job, we take direct lightning strikes nearly every time there's a thunderstorm. Our downtime from such strikes is almost non-existant.  The last time we went down from a strike, it was due to a strike on the power company's lines knocking *them* out, ...
Since my disasterous strike, I've been campaigning vigorously to educate amateurs that you *can* avoid damage from direct strikes.  The belief that there's no protection from direct strike damage is *myth*. ...
The keys to effective lightning protection are surprisingly simple, and surprisingly less than obvious. Of course you *must* have a single point ground system that eliminates all ground loops. And you must present a low *impedance* path for the energy to go. That's most generally a low *inductance* path rather than just a low ohm DC path.
 
Many who did not learn these concepts will emotionally deny what was a well understood fact even 100 years ago.  Protection from a direct lightning strike is so routine that damage is considered a human's mistake.

 

[westom]

I'm sorry to disagree, but even the best SPD/TVSS device isn't going to shunt a direct (or even very close) lightning strike.  Even a low impedance ground could vaporize. 

 
Reasons based in emotion are why so many have damage even if using plug-in protectors; that do not claim to protect from destructive surges.  Electronics atop the Empire State Building suffer about 23 direct strike annually without damage. Some techniques used to protect homes were pioneered in munitions dumps - so that direct lightning strikes need not cause explosions.  Telco COs suffer about 100 surges with each thunderstorm.  How often is your town without phone service for four days after each thunderstorm while they replace that $millions computer?  Never?  Because direct strikes without damage is routine when SPD/TVSS/VPR/arrestor/MOV/suppressor/GDT/avalanche diode/etc are installed using concepts well understood even 100 years ago.
 
But again, since many used ineffective (plug-in) protectors and suffered damage, then many just knew nothing can protect from lightning.  They would blame the protector rather than damage due to ignorance.  Protection has been routine since first demonstrated by Franklin in 1752.  Amazing how Franklin's ground conductor also did not vaporize.   "Even a low impedance ground could vaporize" when one knows without first learning facts.
 
One must learn numbers long before making any conclusions.  For example an 18 AWG (lamp cord) wire can conduct up a 60,000 amp surge.  Since lightning is typically 20,000 amps, then a wire that is four times thicker (ie 6 AWG) connects direct lightning strikes harmlessly to earth.
 
So many professionals contradict what was only an emotional belief.  For example:
 
 

Well I assert, from personal and broadcast experience spanning 30 years, that you can design a system that will handle *direct lightning strikes* on a routine basis. It takes some planning and careful layout, but it's not hard, nor is it overly expensive. At WXIA-TV, my other job, we take direct lightning strikes nearly every time there's a thunderstorm. Our downtime from such strikes is almost non-existant.  The last time we went down from a strike, it was due to a strike on the power company's lines knocking *them* out, ...
Since my disasterous strike, I've been campaigning vigorously to educate amateurs that you *can* avoid damage from direct strikes.  The belief that there's no protection from direct strike damage is *myth*. ...
The keys to effective lightning protection are surprisingly simple, and surprisingly less than obvious. Of course you *must* have a single point ground system that eliminates all ground loops. And you must present a low *impedance* path for the energy to go. That's most generally a low *inductance* path rather than just a low ohm DC path.

 
 
Many who did not learn these concepts will emotionally deny what was a well understood fact even 100 years ago.  Protection from a direct lightning strike is so routine that damage is considered a human's mistake.

 

[kurtmccaslin]

The ARRL published some interesting articles about lightning protection for amateur radio, and many of the principles apply here.  It sounds like you've done a lot already.  You might want to bond your water line to earth ground at your main panel too, as it sounds like there was a large potential across the water pipes and your pump's electrical ground. 
 
Here are the ARRL articles:
 
Part1
Part2
Part3

Thanks for the valuable article.   It is interesting that it shows the tower coax earthed at both the tower and at the building.   This is similar to my situation where I am grounded at both the house and the garage.   I am still confused if grounding the shield at both ends is a good practice.   It certainly could result in current flowing through the shield, but it also gives stray current a shorter path to ground.
 
I looked and found a ground on my water pipes.   My system is all plastic, but has a 5 ft section of copper with a ground wire attached.   However, this section of pipe is more than 75 ft from the single point earthing for the house.   It is quite possible that the current found a shorter path through the pump.

 

[kurtmccaslin]

If the Ditek protector (at each end) does not make a low impedance (ie hardwire has no splices) connection to single point ground, then it is not doing any protection.  If structures are separated, then each must have its own single point ground.  And any wire inside every incoming cable must connect low impedance (ie less than 10 feet) to that ground.  Either directly (ie cable TV, satellite dish) or via a protector (ie telephone, AC electric, ethernet).

This is great advice, but my problem is that the house is already built.   There is a buried conduit from the house to the garage with my data lines in it.   This line comes out of the slab in the center of the house and the center of the garage.   In the garage, the single point earth ground is 50 feet from where the conduit comes out of the slab.   In the house, it is less than 10 feet away.   I tied my surge protectors into this the best I could, but I doubt it is a "low impedance" ground, as there are splices and bends in the wire.   

 

[kurtmccaslin]

Here is an update...
 
We had another storm today.   The lightning was so intense that it sounded like a continuous rumble.  Multiple strikes in the close vicinity.    
 
This storm knocked out an Omni Pro expansion panel and one keypad.   It is interesting to note that the panel and the keypad were the only items in the garage that I did not replace last week.   Apparently, they were weakened by the first thunder storm, and wiped out by the second.   
 
It is also interesting to note that the only items that were destroyed by this storm were on the HAI data bus.  Therefore, I am looking at what I can do to strengthen the protection on the data bus.
 
The data bus is 18/2 stranded burial grade wire with ditek surge protectors at both ends.   (I dont know if the surge protectors are still working)   I wonder if it would be beneficial to upgrade this to shielded wire?

 

[kurtmccaslin]

One more interesting tidbit.
 
I found 2 magnetic contacts that were taken out by the strike last week.   They were melted in the closed position.   It appears that there was a lot of induced current running through the wires in the garage.   Every wire on the west side of the garage seemed to have some kind of damage to the connected electronics.

 

[westom]

he data bus is 18/2 stranded burial grade wire with ditek surge protectors at both ends.   (I dont know if the surge protectors are still working)   I wonder if it would be beneficial to upgrade this to shielded wire?

 
Ditek does not do protection.  Ditek (like all protectors) either connects to what does protection (what absorbs energy).  Or it is ineffective.  You must create a single point earth ground. Even if that means surrounding the house and garage with a buried wire to convert all earth under each building into a single point ground.  Or expanding that earth ground with many interconnected earthing electrodes.
 
Or maybe implementing a ground mesh or incorporating steel inside a concrete floor (if it exists).  But understand. None of what was cited is an induced current. In every case, a damaged item was a direct electrical connection from that cloud to distant earthborne charges.  
 
Induced currents are so tiny that even an NE-2 neon glow bulb would conduct that milliamp current without damage.  Damage means that item was somehow in a path that connected a cloud to distant earthed charges.
 
A shield is grounded only at one end to shield from noise.  View pictures.  If shield is not grounded at both ends for a surge, then the current current will increase voltage as necessary to blow through into other paths - such as into interior wires.
 
More examples of how to create good, bad, and ugly (preferred, wrong, and right) single point earth grounds:
http://www.duke-energy.com/indiana-business/products/power-quality/tech-tip-08.asp