Can a thunderstorm do harm to your DSO

Hi,

I was doing some testing with my DSO when a heavy thunderstorm starts right above my house.I immediately turn the o-scope off because i wasn't sure what the storm can do to it.

What do you think, is it better to turn it off in such weather conditions

When there is severe weather in the forecast I try to go around the house and unplug all electronic equipment such as computers, printers, routers, etc from the wall outlets.

This is not only for protection from lightning strikes but sometimes when there is a power failure there are repeated brownouts and blackouts before the power finally stabilizes.

A lot of my equipment is plugged into a power bar hence I only have to turn off one switch or unplug one power bar for each cluster of electronics.

Just a precaution.

It's not something I worry about in the UK I just carry on as normal and I've never had a problem.

On the other hand your thunderstorms are possibly more intense and your power grid a little less reliable?

If you take a direct strike, or the power pole behind your house takes a strike, lightning can screw up almost anything...

My homeowner's insurance has replaced a TV, several phones, a computer, modem, radio equipment, low voltage yard lighting, house central alarm system.

Turning off the equipment may not be sufficient. A lightning strike voltage surge could arc across the switch connections. It's best to unplug the devices.

In case these guys weren't clear enough, a lightning strike can take out anything it wants. There is no defense against a direct hit. I flip off the main breaker, have a surge protector installed after the main breaker, and unplug those things I hold dear. Usually that's enough. Still, I have had an outlet jump out of the wall and land on the bed, still smoking. I have seen a surge protector case hanging by the wires that used to be connected to the guts of it. I have seen all 3 power terminals of an air conditioning compressor vaporized.

The best you can do is hope you don't get a direct strike and take precautions against a nearby strike. Do not hesitate. Do not hope you will be lucky. Do not stay in the equipment room.

Hi,
Thanks for every one's reply. So even an surge protector isn't enough. I always thought an surge protector will do the thing.

O well, now i know for sure, there's no protection against thunderstorms. Actually i'm very lucky because i've noticed today a tree near my house was cut in half by the lightning.

Even if a direct strike is not very likely to occur. I totaly agree in that the only protection for the latter. Is to remove the plug from the mains outlet. A direct lightning strike in a electrical system will reach havoc.

Hi t06afre,

Isn't there a way the prevent it like a super mains filter with huge MOV's Say for instance two metal o varistors from live to GND and from neutral to GND that can causes a fuse to blow

soda said:

Hi t06afre,

Isn't there a way the prevent it like a super mains filter with huge MOV's Say for instance two metal o varistors from live to GND and from neutral to GND that can causes a fuse to blow

Click to expand...

In a direct hit even those may not be enough. Because so much energy is released.

In my experience there are two classes of damage from lightning strikes, really bad and then there's devastating.
Electrically in the home I lost the alarms, all 3 tvs, the entire Fios system, wireless router, every plug in p/s, vcr's, dvd players, portable telephone bases, hardwired telephones, Roku boxes, hardwired smoke detectors, GFI outlets, my much loved Onkyo A9555s, and some drivers in my Avids and some minor damage to the telephone wiring. Lost the musical organ too. There is evidence of arc over in the light switch box which controls the outdoor mercury vapor lamp up on a yard pole about 100' away.
The surge followed the conductors to the remote garage and destroyed two GFI breakers, the telephone and alarms.
Some electrical appliances did survive so not a total loss.
Structurally the house had two holes blown out of the roof and one hole in a side wall, some of the soffits and rake trim were blown off the house. The missus was home and made comment the power had gone off. Never heard the hit and that mystifies me. It took a week to rid the house of the ozone smell.
The fuse on the power pole transformer opened.
I consider this to be a bad lightning strike.
This would have been devastating but the torrential rain must have extinguished the roof fire just as I arrived not 2 minutes after the strike. The roof was still smoking. Not a good day by any measure but on the bright side we have been here for 30 years and this is the first hit. What are the chances it will happen again? Who knows!
The reason I joined the site was to read up on possible fixes to the electronics. I did manage to replace the ic on the ps for one led tv and it does work but the back light seems to be on all the time even when the tv is off unless unplugged so the control for that is damaged too and probably more as well. I don't use it.
Lightning is a funny duck. To say that protective steps can be taken is a true statement. In the end I believe lightning will take whatever it wants.
From now on I will unplug everything possible when the threat exists.
All the best.

Note also, in the event of a local ground strike, there is a corona around a lightning bolt, quite similar to an " Electromagnetic pulse " weapon, that will raise literal hell with unhardened electronics.
I lost a $6000 Kyoritsu shutter analyser to a lightning ground strike close to the house many years ago, that from onboard evidence, came up through the ground / earth plane, and made " popcorn " out of several chips inside...

We get several very severe thunderstorms every summer - Upstate NY., producing a lot of lightning, I have often considered installing lightning rods on the house...

Antrimman,

Welcome to the forum. Gee it sounds like a war brake loose around your house.

Well i get the picture now and next time i will also unplug the main, mains plug

packratking

What is lightning rods, is it the same as earth spikes

Almost all the horror stories about lightning damage from indirect hits are caused by poor or multi-point grounding in structures resulting in high ground rise potentials. Very good "single-point" grounding also reduces the rise-time induced power surges in local wiring if combined with power-meter whole-house surge protection to stop power line surges.
http://www.dehn-usa.com/manager/fil...eld=publicationId&namePrefix=smImg&idValue=38

nsaspook,

One thing i know for sure is when they build my house about 40 years ago they dig 3m in the ground and lay an earth blanket on the bottom of the hole and then they connect a 3m x 10mm dia copper GND rod to it, so my power setup is quit ok.....i hope!

I've lived in northern Illinois, where lightning storms are quite common, for over 50 years. I'm not aware of anyone around here taking any special precautions against lightning strikes, other than saving your work and shutting down your computer if the storm becomes intense. Everyone uses cheap "surge protectors" but we do not normally unplug things for every storm.

My home has been hit by minor strikes maybe twice. These strikes blew out the sump pumps and in one case caused smoke in the attic. (That was a bit tense for a while, as we tried to figure out where the fire was. The smoke eventually cleared and we never figured it out.)

If you've ever seen the results of a direct strike, you'd realize how futile it is to try to "absorb" one. I've seen 3-ft thick oak trees exploded from the inside out.

Folks around here carry insurance against this sort of risk, and otherwise have a fatalistic attitude - a hit is rare and if you're unlucky, file a claim and get new stuff.

wayneh,

It is like you say. There's no reason to over react because of one storm, but here it happens at least once a month and then it's usually heavy. Here one always loose on insurance payouts. You never get back what you had before.

My sister had a lightning strike a few years ago, took out the stereo, comuter, refrigerator, and more. it came in the phone line and got into the house wireing through the modem, into the comuter, and then everything else.
unplugging the line isnt enough, the phone lines can bring lightning in too.
cliff

soda said:

Hi t06afre,

Isn't there a way the prevent it like a super mains filter with huge MOV's Say for instance two metal o varistors from live to GND and from neutral to GND that can causes a fuse to blow

Click to expand...

With a nearby strike, the problem rarely is line to line or line to ground voltage; it is transient current flow along any conductive object that causes the most problems. The average lightning strike is over 40,000A, with a pulse that lasts only 10s of us. The inductance of conductors causes a voltage gradient of > thousand volts per foot of conductor.

MOVs are hugely over-sold and over-promoted.