The Power of Lightning

[MtnDon]

Not sure how this relates to a travel trailer, but we had our high mountain cabin struck by lightning. Many electric / e;electronics devices were toasted. Cabins and homes are grounded, connected to earth, trailers are not. And rubber tires are not actually good lightning insulators. Hard metal shells protect the contents some.

anyhow for those who may be interested...

Lightning struck the cabin and three tall pines nearby. It seems likely this happened Wednesday evening, July 16. There was a severe thunderstorm warning for the area that evening. We were not at the cabin; we had left on the 11th. The rain gauge indicated 1.75" of rain and the water tracks on the slopes would seem to back that up.

We arrived Thursday morning the 17th. While Don was outside turning on the power to the inverter, Karen was inside puzzling over the pieces of plastic debris on the floor inside the cabin. When Don closed the breaker to power up the inverter he was greeted by a pop from inside the inverter and then a curl of smoke; the breaker then popped open. Don went inside. He noticed the plastic on the floor was from the wall plate cover for the 24 volt ceiling fan. Looking at the wall he saw the fan control dangling from the wall box. The wall was slightly blackened at one corner of the box and electronic parts were blackened as well.

Damages we discovered included:

The Outback VFX3524M power inverter / charger is non functional and has something burnt inside; smells like the magic smoke escaped.

The Outback FM60 charge controller is non functional and we can see some small electronic parts have been blown open. The magic smoke has definitely escaped. When unmounted from the wall various plastic and semi conductor shrapnel fell out.

The data cables interconnecting the charge controller, hub4 and inverter / charger have blackened connectots. The socket at the charge controller end blew off the circuit board.

The circuit breaker between the PV panels and the charge controller exploded. The top of the casing blew off and a hole was blown out one side. The breaker to the batteries tripped but is apparently undamaged.

The PVC conduit that carries the wires from the PV panels up to the cabin charge controller exploded open in ten different spots over a hundred and forty foot run. At one point the insulation on one of the wires is melted. All breaks occurred at the glue joints. ??? Only two joints in the 140 feet were undamaged. Further up the hill the conduit was undamaged.

The lightning arrestor on the PV mount pole has the end blown out of it. The ground wire from the arrestor to ground lug has melted insulation.

One fuse in the 24 to 12 volt converter blew violently, incinerating the fuse housing and leaving mostly ash behind. The second fuse housing was intact but very blackened. Unfortunately replacing the fuses did not restore functionality.

The LED Christmas lights strung along the porch and north wall to the shed were severely damaged. One 5 foot stretch had all the LED’s and their sockets blown over a 7 to 10 foot radius. At the back end of the cabin the light wire was blown apart, completely severed. There are flame or electric arc marks on a one foot length of fascia board along the roof gable end.

A join in the aluminum gutter on the south side of the roof was blown apart. There are light grey ghostly trace marks like contour marks on a topo map on the white paint.

There are black scorch marks around the bolt head where a ground wire connects to the metal roof.

At the gazebo where the 120 VAC electrical conduit emerges from the buried line there used to be a 90 degree PVC elbow fitting where the wires enter the gazebo wall. That elbow was blown apart and pieces found up to 40 feet away. That circuit is entirely external to the cabin. The circuit breaker buzzed loudly when trying to reset it. Testing indicates the GFCI outlet that is first in the chain of electrical connections, blew. At least with the GFCI temporarily jumpered the breaker resets.

Three trees approximately 20 to 30 feet from the SW cabin corner show ample evidence of lightning strike. Bark chunks, strips blown off and many small branches littered the ground. We can see strips blown off way up the trunks and closer to the ground. Strangely in the more or less center area of the three trees that were struck there is an equal sized tree that was untouched.

When I rewired things to by pass the toasted inverter / charger and temporarily connect generator power to the cabin the fan on the propane wall heater ran and would not shut off. That fan is only supposed to run when the heater is hot. There are small scorch marks on the receptacle and heater fan power plug ground connector. One thought is that the lightning power entered the heater via the exterior direct vent ductwork. The ground wire from the fan cord connects to the fan motor which is bolted to the metal combustion chamber. The thermostat switch is mounted to the exterior of the combustion chamber. That switch was found blown apart. ....

The LCD TV will not power up at all. The DVD-R clock lights when plugged in but the unit will not power up. Both were plugged in but the wall outlet was turned off. The TV antenna cable was connected though. The TV antenna lead in wire was connected to a ground rod via one of those coax wire terminal blocks.

The Yamaha inverter generator was connected to the cabin power system via the inverter / charger. The engine starts, but the engine races at maximum speed and there is no power at the outlets. The outlet that is supposed to provide 12 VDC for battery charging produces approx 36+ VDC. It would appear the magic smoke escaped from the generators electronic speed and power control system.

The portable air conditioner ran for 5 seconds and then the LCD display went dark and the motor ceased running. It has not wanted to resume operation.


The good news is that the PV panels are still producing power. The batteries were fully charged with a reading of about 25.3 volts on our arrival and in seemingly good shape. Neither the cabin, out-buildings or the forest caught fire. I wired up a temporary jumper to provide 12 volt DC to the DC powered lights and water pumps. The microwave works as do the other small appliances...using generator power.

Photos to come

[lrrowe]

MtnDon,
Wow, what a story! I am sorry to hear about all the damage.
But I am glad to hear that you did not have a fire and that you and your wife were not there and not hurt.

[MtnDon]

Christmas tree LED lights; LED's blown apart, slight scorching on fascia, hard to see with the string still in place




Must have been some big sparks flying here. LED light string blown apart. The LED string made a 90 turn at the eye where it then ran to the shed along with the TV coax and a carrier rope. I'm thinking of spraying a clear coat on that to preserve the memory.




Bottom of one of the struck trees. It's difficult to get good photos of the strips torn off in 8 foot lengths farther up thr trunk. Those extended 50 feet or so up the tree.




One of the other struck trees. We'll have to wait and see if they are affected.




Power line entrance to the gazebo.



That was a fitting similar to this...




The fan speed control. The pot (with the black knob) blew apart and slifgtly scorched the wall as it fragmented the wall plate.




The DC breaker that exploded. This was the breaker at the charge controller in the incoming line.




The FM60 charge controller connections panel. The green data cable connector socket was blown apart. Other assorted debris, some of which is in the bottom of the CC. Scorch marks.

[MtnDon]

The smallest conduit fracture




One of the longer fractures




And the one section where the insulation was melted




Assorted souvenirs. The white pieces are the fan speed control wall plate. The black device is the DC circuit breaker. 150 VDC 15 ampere. In the center are gazebo box parts and some conduit.




The propane heater fan thermostat




The plug and receptacle it was plugged into




The roof panel; 24 gauge steel. The photo was taken after I gave the bump a couple of whacks and tried to tighten the screw which was backed off or pulled out about 3/4 inch. I need to get some larger gauge screws to be able to tighten that down correctly.

[bobhenry]

Lot to be said for lightning rods !


Might be a good lesson for others to isolate the dc circuits
during long absences with a series of knife switches ?????

[Shadow Catcher]

You have your work cut out for you but at least no fire. How much will be covered by insurance?

[MtnDon]

You have your work cut out for you but at least no fire. How much will be covered by insurance?

First of all we have a very high deductible; probably close to a wash, so we're not going to bother doing fine calculations.
Also we're not going to claim as being in an area with high wildfire danger we'd rather save any claim in case we need it if the whole thing goes up in smoke.

[angib]

Wow! I'm amazed at how many separate bits of damage were caused.

Should I send you a bottle of this?

wiring-harness-smoke-1.jpg (22.28 KiB) Viewed 2449 times

[tony.latham]

Good grief! You sure it wasn't Al-Qaeda?

Glad nobody was home and the place didn't burn down. Quite the project you've got but I know you well enough from reading your posts that you're the man to handle it. Even with the remoteness to your place. Quite the list of parts you're going to have to develop.

I'd suggest this winter (after you've almost got the place rewired) have a photobook of the near-disaster made up to keep at your cabin. Someday this will just be a bizarre story for your house guests to absorb by flipping the pages.

Sheeeeeesh.

Tony

p.s. we were pounded by lightning last night... probably new fires this afternoon...

[MtnDon]

Should I send you a bottle of this?

Dang, I could have really used that back in the days when I had a BR Green Sprite I called Froggy. Maybe if it is sorta generic smoke it might work on todays electronics.

[GuitarPhotog]

The replacement smoke only works on wiring harnesses. Don needs solid state device smoke and circuit breaker smoke ;-)

<Chas>

[48Rob]

Don,

I'm glad to hear you weren't adjusting the fan speed when the lightning hit...

Rob

[bdosborn]

Should I send you a bottle of this?

No, it's earthed wrong.

Scarey stuff Don, you could might into a Lightning Protection system. Kind of expensive but then again so is what happened. It's been quite a while since I designed a LPS but here's what used to be the best website for design info:

Thompson Lightning Protection

Bruce

[MtnDon]

Thanks for the link Bruce. I found that site earlier today. I've been using it and a few others following design suggestions and what is required by code in some locales, making a list of materials, broken down into categories that are divided into; Cabin, Shed / antenna, Barn, Gazebo and PV pole. Divided up so I can see if we do an all at once or prioritize. There are even ground enhancement devices and materials to ensure better electrical conduction to earth. Never had any clue about that before. So far the costs to protect the cabin structure seem to be much less than the value of the contents that don't work anymore. I have also ordered several of the Midnite Solar suppressors today along with one of their charge controllers.

[citylights]

Wow, great story. Back to the question about grounding...

Is it better to ground a teardrop, in the hopes that the lightning will follow the ground?

Or is it better to not ground a teardrop, hoping that the tires will insulate it and not get struck by lightning?