Lightning strike

[ct03911]

A week ago I sat in my kitchen during a heavy thunderstorm. Actually saw a bolt of lightning thru my skylight which had to have either hit my detached garage or right next to it from the angle.

The noise and flash were tremendous and I ran out expecting a fire. Nothing. No smoke, no ozone smell. No marks anywhere to be seen, even on the copper cupola.

It cooked my home ADT alarm motherboard, three smokes and the detached garage motion sensor. Also killed one garage door opener in the main home.

As to the rest of the detached garage it's interesting. Besides the motion sensor, three 20amp breakers were tripped for three walls of outlets. On each of those circuits was 5-7 outlets but every outlet in the garage is a GFI.

The first outlet in each tripped circuit was toast but then one or two others in that circuit were damaged too. A total of 8 GFI outlets were damaged. It would kill the first one and then skip one or two and then kill another one. Weird. I can't see any wire damage in the boxes but the insulation covers all the other runs. Not sheetrocked yet.

I also had one 30amp 10ga wire running 220 across the garage to a window ac outlet. That breaker was not tripped and tests good but the outlet does not have power. I must have that wire run damaged somewhere behind the insulation.

I replaced the three 20amp and one 30Amp breaker (to be safe) and all the affected outlets obviously. All set out there now except I'll have to run a new 10ga wire from the box to the window ac. Pull my stuff out, pull insulation down, yank the bad wire and replace etc etc.

I also need the new door opener and I'll be all set.

I'm most surprised by the fact I can't see where it hit and how the damage kind of skipped around some outlets and not others.

 

[dragrcr890]

With the voltage of a lightning strike, it wouldn't necessarily have to hit the house to do damage. I'm no expert on lightning but I do work inside substations. I can stand 25 feet under a 345,000 energized line and hold my multimeter referencing ground and reach as high as I can and measure 300vac steady... so with a few millions volts...? you could have 1000volts of induced voltage on random items and fry things randomly. pretty impressive!!

 

[TractorJeff]

When I was young, it hit the TV antenna pole which went to ground. Still blew out an electronic battery charger in a detached shop and raised the hair on my arm. So, yes it does skip around!

 

[wyliesdiesels]

I use to work on dispatch centers and radio towers.

We had an AMR dispatch center with a 100+' tall tower on top which took a direct hit but nothing got damaged.

The reason? Everything was properly grounded and at the same potential.

We had to do a grid of grounding electrodes for the tower and building and make sure all dispatch stations, consoles, rack equipment, transmitters, servers, etc were all bonded and were at the same potential.

Motorola spec'd it all out and we installed it.

The point of my story is that you should make sure that your GES(grounding electrode system) is up to snuff.

What type of electrodes do u have for the detached garage and home?

What parallel pathways do u have between the 2 buildings?

 

[ard]

I'd have talked to my insurnace and gotten a fat estimate from an electrician, to make sure EVERYTHING that might have been affected was addressed/replaced. If I did it or had it done, I'm thinking I would want the claim in place. Even with a 2500 deductible, it might have been worth the exercise....

 

[CoogarXR]

One of the last places I worked as an IT guy, we had a good lightning strike. It came in through the cable modem. Blew them modem, blew the NICs on the linux router, blew the 24-port switch, jumped to the 32-port serial server that served a bank of high-speed (expensive!) multi-part-form printers. Cooked the serial server and all of the serial interfaces on the printers.

That was an expensive storm...

I spent many years doing electronics repair too, and I would say that phone and cable lines take a hit more often than power lines. I saw so many modems with holes in them, lol. And tuner boards on TVs. Good times.

 

[sberry]

Yes, old modems to phone lines were bad especially if they were hooked to puters which were grounded thru the electric.
One reason or maybe even the main one as Wylie pointed out was an issue with the uffer, it was hunting for a ground. The strike hit something ungrounded. I saw this on a metal skinned wood framed shed, wasn't grounded but for the electric and the rods at the pole rotted off, finally found its way to the well pump as the casing wasn't electrically grounded either.
This happens all the time. I used to get hit thru phones all the time till I figure out wtf and properly ground the arresters on the service, all wo0rked as sposed to since, never another hit. I talked to the phone guy and he pretty much clueless and "just don't understand why" which is all th more reason to follow the instructions,,,, but no one in the whole company has had a class or read the book.

 

[penright]

Lightning does some weird things at times. My bother-in-law's house was "hit". You could see the arc path in the sheetrock, where if followed the moisture /sap that was in the 2x4. It popped nails out of the wall. Then he installed "lightning rods" and have not had a issue. One thing we learned, "lightning rods" is not to carry a strike, but prevent one. As the charge tries to build, it keeps letting it find ground, so it never builds enough to strike. At least that what we were told.

 

[bigcreek]

My inlaws live next to a small river and found a place in the riverock where they believe lightning must have hit because there was a roughly 3' circle where the river rock was literally melted together into a glass looking substance with the outer portion of the melt obvious rock. Not exploded but melted. Very strange thing to see. Pretty cool. That rock is from a few inches to around 10" in size and all smooth.

 

[ct03911]

The house and detached garage are both grounded to earth.
They are connected by 100amp underground copper service.
A separate conduit holds the alarm wires.
It's just funny how not just the first gfi but others on a circuit were effected.
I have 5 +/- outlets in each circuit. All gfi.
It killed the first one on three walls and then skipped to another one or two further down that circuit.

 

[ct03911]

While my detached garage is not done, lighting and a few other minor issues before drywall, it's mostly done. My main home 2-car garage is a mess and on the upgrade list.
Now that I'm having new door openers installed I took the time yesterday to pull out all the old exposed door opener wiring and recess it.
I also pulled some old questionable outlets.
I am now motivated this get going on the wiring upgrade in there and get it ready for insulation and drywall.
Bolt of lightning motivation.

 

[rlitman]

With the voltage of a lightning strike, it wouldn't necessarily have to hit the house to do damage. I'm no expert on lightning but I do work inside substations. I can stand 25 feet under a 345,000 energized line and hold my multimeter referencing ground and reach as high as I can and measure 300vac steady... so with a few millions volts...? you could have 1000volts of induced voltage on random items and fry things randomly. pretty impressive!!

There's that voltage field issue for sure. But because the lightning current comes in the form of powerful pulses, there is also a lot of induced current in anything nearby as well. Enough that pieces of iron outside the current path may become magnetized.

Lightning does some weird things at times. My bother-in-law's house was "hit". You could see the arc path in the sheetrock, where if followed the moisture /sap that was in the 2x4. It popped nails out of the wall. Then he installed "lightning rods" and have not had a issue. One thing we learned, "lightning rods" is not to carry a strike, but prevent one. As the charge tries to build, it keeps letting it find ground, so it never builds enough to strike. At least that what we were told.

That's the idea behind those "poofball" looking lightning rods (the ones with lots of points).

I'd have talked to my insurnace and gotten a fat estimate from an electrician, to make sure EVERYTHING that might have been affected was addressed/replaced. If I did it or had it done, I'm thinking I would want the claim in place. Even with a 2500 deductible, it might have been worth the exercise....

One thing I'd do is unplug EVERYTHING, remove anything electronic (down to dimmer switches, GFCIs, even circuit breakers), and use an insulation tester on any wiring you plan to leave in service. Just to be sure that wiring that appears ok does not have some invisible carbonized path to ground that will start a fire down the road.

 

[ct03911]

Thanks rlitman.
I probably need to call in an electrician to check everything.

 

[Junkman]

I live in Northeast CT, and had a number of terrible experiences with lightning. Almost every time that we had a lightning storm, our well pump would be blown out. I replaced them a number of times, and it was so frequent, that I purchased a spare. Then we moved, about a 1/4 mile away, and haven't lost another well pump in the last 30+ years. The only thing that I can think of is that when this well was drilled, that they hit a different vein of water. We never saw the actual lightning strike, but we always saw the effect of it. At the new home, there are about 6 ground rods that are connected together from the electrical panel to the service entrance, and then to the well casing. The old electrician that I consulted with about the lightning strike problem, said that the more ground rods that you install, the better they work. Don't know if that was sage advise, but it was inexpensive insurance.

 

[marinusdees]

Lightning doesn't have to strike directly to do damage. It induces current of varying voltage in any conductor. The farm boys where I grew up in Michigan would come to school laughing about how the phones rang all night. It took about 70 volts to ring the bell, and the lightning could be several miles way. Sometimes blue flame would shoot out of the phone. Where it hit directly in the field, it would burn and severely stunt the plants (celery, pickles, potatoes, etc.) in a circular pattern of varying diameter.
I have a clothes line of plastic covered wire, endless loop on pulleys. Years ago, lightning struck the tree to which one end was fastened. Blew out the TV distribution amplifier I had in the attic, little other damage. You could see the spiral pattern in the bark of the Doug fir. We weren't home at the time.

 

[remauto1187]

Lightning does NOT take the least path of resistance to ground. It takes ALL paths of resistance to ground or just some of them. This is why when a house gets it in the service entrance you could lose your refrigerator, tv, microwave but the alarm clock and dishwasher are just fine.

 

[Jeepster04]

Parents house took a somewhat direct hit 5-6 years ago. We started finding shingles laying out in the yard and thought some loose singles were getting blown off. After checking out the roof we found a ~6" diameter hole right at the peak of the house. I was certain someone had fired a cannon ball straight up into the sky and it went through their roof. Even went into the attic to try and find some object that went through their roof.

At the time, they weren't living in the house so we didnt find everything immediately. Directly below the hole was a half bathroom. The bulb had exploded in the light for the bathroom. Then we found a garage door opener wasn't working and the stove igniter was bad. After awhile we figured out lightening had blown a hole in the roof... Kinda wild..

 

[ard]

Lighting takes the path of most expensive resistance....

 

[bgarrett]

How many of you have lightning rods on your house or shop? I'm going to guess 'not many'.

 

[softailgarage]

How many of you have lightning rods on your house or shop? I'm going to guess 'not many'.

I make the wife wear a tin foil hat and sit on the roof when there's a thunderstorm...helps with TV reception as well.

 

[larry4406]

I don't.

The above posts are an interesting read.

In my current house, been here 4+ years, we have had two different lighting events that I am aware of.

First fried my desktop which was connected to a surge protector/UPs. We were in the room when it happened and could feel the static and quickly smelled the burnt smell. Connected to Comcast gateway/modem Replaced computer and moved on.

Also had a "Hot/Ground reversed" condition which suddenly appeared after the computer fried. I am guessing collateral damage from the first strike.
https://www.garagejournal.com/forum/showthread.php?t=296706

Later we had an event that fried the HDMI inputs on my Sharp TV and a blueray player which was connected to the TV.

After the HDMI/bluRay fry event, I discovered that although the Comcast signal was grounded, it had its own ground rod where it entered the house, not the same ground as the main panel; this has now been fixed. I have also installed a TV antenna and researched its grounding.

I need to put in surge protector breaker in my main panel. I have a Cutler Hammer CH panel 200A.

 

[wyliesdiesels]

How many of you have lightning rods on your house or shop? I'm going to guess 'not many'.

Why would you guess not many?

Do you have any actual experience with that?

In all my years of being in the field, Ive only come across 2 houses that didnt have rods out here.

And BTW, rods are not the only code permissable electrode...

 

[Lelandwelds]

everything was properly grounded and at the same potential.

. . . were all bonded and were at the same potential.

The Comcast signal . . . Had its own ground rod where it entered the house, not the same ground as the main panel; .

My understanding is you can have an ufer, bond a bunch of metal pipes together willy nilly, or drive half a dozen ground rods. You just must have a single wire connecting to panel box. All others connect to first rod.


My grandparents house had a lightning strike follow the copper propane line, blow a hole in living room floor, and provide an exciting 5 ft tall flame while they were cooking dinner.

 

[ripperd]

Why would you guess not many?

Do you have any actual experience with that?

In all my years of being in the field, Ive only come across 2 houses that didnt have rods out here.

And BTW, rods are not the only code permissable electrode...

I'd guess he was referring to aerial lighting rods, not ground rods.

 

[bgarrett]

I'd guess he was referring to aerial lighting rods, not ground rods.

Sorry. I thought I was speaking Standard easy to understand English when I said 'lightening rods'. I am amazed that anyone would confuse a lightning rod with a ground rod.

 

[larry4406]

everything was properly grounded and at the same potential.

. . . were all bonded and were at the same potential.

My understanding is you can have an ufer, bond a bunch of metal pipes together willy nilly, or drive half a dozen ground rods. You just must have a single wire connecting to panel box. All others connect to first rod.

In my case the Comcast ground was an isolated independent ground rod. That rod and Comcast is now grounded common with the house ground.

My understanding is you want a common single point ground.

 

[sberry]

My neighbors took a hit. The insurance adjuster and them figured it "hit the well" but they just guess. What did happen was it hit an ungrounded tin shed they had hooked thru an outside outlet. It zig zagged thru the place, took out a couple fixtures, a tv and went thru the panel, on to a main panel on a pole which had a broken conductor to the rods and terminated thru the wire feeding the well.
There were several things wrong with the electric that added to it.

 

[Chukster]

We had a strike to the trees in the back yard; about 3 or 4. A lot of the strike came down the biggest/tallest tree, then jumped out of the tree at about the 3 ft level and went to the 14ga. wire for the dog's invisible fence; followed that into the house & blew the controller off the wall, leaving the soot mark on the paneling. We also found bits of wood that looked like the old excelsior wood shavings, but in about palm-sized pieces all over the back yard and deck. Looked kinda like expanded sheetmetal, but of wood; I figure it was the water flashing to steam as the strike traveled thru the wood.

Younger DD had just got home from school. She related it this way: "There was a flash and a boom, same time. All the windows were purple. And the next second, both dogs & I were under the kitchen table, my arms around them & we were all quaking!"

Poor kid, she's generally completely fearless, but ever since then she's been agitated by storms, until her best friend made her sit thru a a North Carolina T-storm one afternoon, telling her "It's OK. You're alright. And it will be over soon."

For some light reading on grounding and such, look up "Motorola R-56 Telecommunications Site Standards"

 

[ard]

My father-in-law worked designing and installing lightning protection systems for a solid rocket motor production facility.

You get that wrong, and a blown up TV is the very smallest of your concerns.....