Been struck by lightning?

I like the jumper cables to ground.

I was in the jumpseat of a 727, sitting behind the Captain, when we got struck twice in about 3 minutes. We were landing at PDX (Portland) and the First Officer was flying. It had been a rough ride already and we were belted in very tight. Still, I could swear the Capt. almost hit his head on the overhead panel the first time we got hit. The Second Officer went down the systems checklist quickly in a very high-pitched voice, then grabbed the cabin PA microphone and, in a very low, soothing, voice told the passengers that all was well. As soon as he replaced the mic, we were hit again on the FO's side window frame about 6 inches from his right hand. Oh, by the way, he was hand flying at the time because the autopilot kept kicking off in the turbulence. We also, due to the high crosswind, were landing on a runway they had never landed on. Once on the ground, the 4 of us in the cockpit started laughing so hard that we had tears in our eyes. Relief of tension. The SO then opened the cabin door as we taxied in. I will NEVER forget the look of fear on the 1st Class pax faces. And that's why I prefer to ride in the pointy end of an airplane. ;)

LS

sleepy wrote:
H...my camper never has any sort of contact with earth except the rubber tires which don't conduct electricity... no ground.. .

How did you put tires on your truck camper?

Lightning will seek the quick ground path. A few years ago we were in the Maryland State Camping Park on Assateague Island when a small class A type was struck. The bolt went thru the vehicle destroyed most of the electronics and much wiring including the shore power cord and outside power box. It appeared that most of the charge, not all, exited thru the built in jacks which were then welded in the down position. A crane was used to put the camper on a carrier.

Fortunately the folks in the camper were not injured physically but were very shaken up. My belief is that it's a reasonable idea to insulate with a pad under our jacks to reduce the ground plain. I think the rubber tires offer a little insulation but steel chords as in 19.5" "H" rated tires work against the principle. Keeping our Karma straight might be our best hope.

camperpaul wrote:

Dweikert wrote:

Interesting that the burn marks are on the power terminals while the ground looks unscathed.

The "burn marks" are what I expect to see after plugging in to a corroded outlet.

Farmerjon wrote:

X2
maybe because the neutral was grounded?

The round pin is "protective ground" not neutral.

(fixed the quote names:))

Properly wired, neutral and ground should be commoned at the distribution panel. The difference being current should not flow through the ground thus maintaining it's ground potential at all outlets. In a circuit drawing power, neutral will have current flow so there will be some voltage potential to ground measured at the outlet due to the drop across the neutral wire between the outlet and distribution panel.

I agree the burn marks look like usage in a corroded outlet, not to mention the terminals themselves look corroded. But I got the impression the photo was showing damage from the lightning strike and, if that is the case, it looks like poor grounding either in the camper or the outlet it was plugged into at the time.

While typing, it dawned that another option is the lightning induced a high voltage onto the power line so the burns could have come from voltage induced onto the panel side of the plug, not from the camper side. Though that would have affected other campers plugged in nearby.

sleepy wrote:

tony lee wrote:

except the rubber tires which don't conduct electricity... no ground.. . no worry maybe.

If lightning can jump several miles through air, a little bit of rubber isn't going to worry it too much.

Lighting will always seek the best ground and the easiest circuit... won't it?

If there are multiple paths to ground at the point of a lightning strike, current will be present in each of these paths. The current in each path will be proportional to the resistance of each of the paths to ground albeit the path of least resistance will carry the bulk of the current.

DWeikert wrote:

Interesting that the burn marks are on the power terminals while the ground looks unscathed.

The "burn marks" are what I expect to see after plugging in to a corroded outlet.

Farmerjon wrote:

X2
maybe because the neutral was grounded?

The round pin is "protective ground" not neutral.

Edited to correct quotation names - thanks Dan.

Not always straightforward. Many boats have very little metal framework inside the superstructure so radio antenna get the first hit and then the electrics cop it. New composite aircraft have similar problems and they have to add conductive paths and use hydraulics and fibre-optics to try and protect the avionics and controls. Any Faraday cage effect is likely to be incomplete

My 4WD living quarters is frameless and built from fibreglass.foam sandwich panel so there may be no Faraday cage effect at all - apart from some aluminium trim around the edges. Still got a radio antenna and wiring so I imagine there is still the same risk of lighting strike, but with increased risk to contents if there is a strike.

DWeikert wrote:

fla-gypsy wrote:

Interesting that the burn marks are on the power terminals while the ground looks unscathed.

X2
maybe because the neutral was grounded?

Supposedly, the structure of the vehicle will transport the lightning around the occupants -- this is an example of a "Faraday cage." Here is an article:

Faraday cage

Quote: "Automobile and airplane passenger compartments are essentially Faraday cages, protecting passengers from electric charges, such as lightning during a thunderstorm."

I would also guess that since the wheels are usually wet during a thunderstorm, the fact that they are rubber is not hugely important. The vehicle may be somewhat less attractive than other nearby targets.