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The fast rise time of the lightning-jolt into an iron core transformer,
results in a high input XL (measured in ohms) which makes
the transformer a somewhat protective device.

The turned OFF lighting flashing ON during a nearby strike might have been EMP effects.
The LEDs are diodes and will convert any strong magnetic field pulse into a short burst of DC voltage.
The wires between the transformer and LEDs (and between LED elements) act like an antenna.
If you had a Ham radio guy living next door, your LEDs might be flashing every night! :eek:

The other explanation for the flash is a high voltage arc jumping past
the switch contacts and charging the primary of the transformer with
one quick jolt of power..

I like the EMP theory, since my Ham HF radio forced me to add ferrite RF blockers on my solar HW controller's sensor lines.
The high resistance of the thermistors and the long wire run up to the roof,
made that circuit a perfect HF antenna. The relays were banging like crazy
when the SSB transmitter was running. :o

~~~
The reason EMP generators are weapons against solid state devices (Computers & LEDs etc)
is because many of the semiconductor junctions in these devices can be badly damaged by a little too much current.
That's also the reason you need to wear a grounded static strap while working on your PC mother board.. :)

EMP is also the reason preppers (and the DOD) build EMP shielded storage containers,
to store their emergency back-up electronic devices.

Nice, thanks!

I was wondering if it was EM. There's about 35 feet of wiring between the switch and the LEDs in the wall, which would make for a pretty good antenna.
It shouldn't be an arc over the switch, since the switch is after the transformer (which is fully electronic, so no iron core/coil).

Anyway, I think with a modern electronic transformer, you'll end up with pretty good protection against power surges and similar mishaps such as short circuits. You could add separate surge protection before the transformer if you wanted to be sure, but I'm not certain what off the shelf options are available.

I think you have wrong information about led lights they generally do have long life span.

I've got 20 120VAC LEDs installed.
 

LEds video by Xringer | Photobucket

And, I've had four go bad, after less than a year.
So, I wouldn't necessarily recommend this brand to my friends.

Which brands went bad on you?
I watched your video and it looks like you have at least two different brands and one looks like a phillips.

We got about 6 of the phillips we've been using for close to year now without any problems but these have a 6 year warranty on them which is nice.

The Phillips LEDs are fine.. But the Lowes Utilitech 40w and their designer blubs aren't so good. Infant mortality maybe..
The last one started to strobe but the others just stopped emitting.