Lightning: Not Always a Hit

Lightning is a very unpredictable force of nature. The voltage is varied and severe. There is cloud to cloud lightning and cloud to ground lightning. In the world of consumer electronics, when lightning "strikes" damage our equipment, we concern ourselves mostly with cloud to ground lightning.

This phenomenon happens when negative electrons accumulate in the clouds and look for the shortest route to ground. In large cities, skyscrapers are equipped with lightning rods on top of the building in order to shunt the lightning to ground. This usually prevents any damage. However, in the consumer or residential area there is really no protection with the exception of high towers, trees, etc. When I was a young man, I witnessed a direct strike on an oak tree. This tree was probably a hundred years old. The lightning immediately boiled the sap in the tree causing it to explode into splinters. This is a horrifying and deafening example of Mother Nature's fury.

My point to this article is damage to consumer electronics with regard to lightning strikes. Lightning does not have to make a direct strike to your home to damage electronics or appliances. It is indiscriminate and unpredictable.

I worked in the consumer electronics industry for over 10 years and had many experiences with lightning damaged VCR's when they were popular and other electronic devices. These basic priciples are applicable to todays innovative electronics.

What happens are lightning strikes close to a home and these strikes"induce"electrical spikes in your equipment, sometimes rendering the equipment unrepairable. Picture this scenario...the wiring in your house goes all the way through the home and although it doesn't make a circle, it is equivalent to the side of a transformer in which high voltage is induced. This causes a spike in voltage that will do what lightning does...what it wants. It is unpredictable.

There are safety devices in your consumer electronic power supply that are installed to quell damage from lightning, but they do not always work. There is usually a fuse, which should "blow" but doesn't always do so. There are isolation transformers (these are transformers with the same winding that separates incoming voltage and induces the exact same voltage in the secondary for your unit to operate), these transformers are often "fried" or just jumped altogether by the high voltage. This allows the high spike to destroy your power supply and possibly jump it altogether and damage circuits further into the operations of the unit. There is also a thermistor that should immediately shunt the spike to ground, but doesn't always work.

The rule of thumb I used in diagnosing lightning strike damage in electronics is, if it somehow jumped the primary side of the power supply, odds are you would have trouble in the future with your machine. Maybe not, but it is best to exercise on the side of caution. This is the reason: Integrated circuits are connected by microscopic pieces of gold wire. The lightning could have caused a "nick" in the circuit line, and even though it operates properly, there is a high probability that the heat from the integrated circuit could cause the nicked connection to open in the near future. This would render the unit useless or cost another repair bill. The strike could have done the same type damage to the multiple integrated circuits in today's electronics.

After several experiences of this sort, I began to rule a unit terminally damaged by lightning if it "jumped" the primary power supply. It is safer to say that lightning has damaged the unit beyond repair than to experience tremendous trouble and expense to the consumer down the road. There is no way to be absolutely certain but, it is best to be cautiously pessimistic where lightning is concerned. Lightning induced through a TV cable wire is a common route. Please disconnecte cable and unplug your electronics in the event of a storm. Remember your computer as well.