Thunder and Lightning safety

[Coldicote]

Is it wise or necessary to disconnect TVs and computers during a thunder and lightning storm? Sometimes, just to be on the safe side, I unplug my PC from the power socket and its phone connection, and also the TV from its power socket and the aerial. I really don't know whether this is necessary and would welcome comments.

[ojread2]

I sit at my PC awaiting any replies myself
I've always thought this largely to be untrue. But I suppose your house can be struck by lightening, but that is hardly a common event and I suspect the odds are somewhere in the region of a zillion - 1
I don't know - interested to hear though

[chas2008]

thats the official line (apart from the phone line) but in reality few people do including me and i did have a TV wrecked by a lightening strike to my aerial a few years ago so i should know better..(at least the house insurance covered it)...
Thats basically what a surge protector is for...

[gingejbee]

Not sure about the zillion-to-one. Several years ago, my aerial WAS struck during a storm and "goodbye TV" (didn't have a VCR). No visible damage, but TV completely dead when switched on in the evening. Repair man confirmed lightening strike and insurance paid out in full, just four days later (MoreThan).

[gingejbee]

...well, that's TWO of us!

[deggers316]

i do but only if it getting very near, not when the gap between the flash and thunder is around 5 seconds
but its best to be on safe side if your not sure

[emmie]

Lost the radio completely for 10 minutes, don't know what happened but we are in middle of big storm. It keeps on going off station as well, no idea.

[Coldicote]

Interesting answers here thank you, and I'm glad that I'm not the only one to be a bit 'on edge' about it. Who actually fits a surge protector - is it something to do with the mains service providers or can one be fitted in my own home?

[scotman]

Most of the trailing multi-plug things come with some degree of surge protection. Belkin seem to be one of the main manufacturers.

Maplin sell them and other stuff

http://www.maplin.co....eria=surge+protection

[Berkshirelad]

@deggers.

Absolutely not as the storm is coming nearer. You do not know either teh speed or direction of travel and yoiu certainly do not want to have hold of the aerial lead if the antenna is struck.

[redcrx]

suffolk fire service seems to have at least one lightning strike on a house being attended at moment. The storms are quite big here.

[chas2008]

large companies do as a must, imagine the hassle if say a hospital took a strike...
http://www.amazon.co....20protection/products

[emmie]

we have had this storm most of the afternoon, haven't tried the tv, if it doesn't work, there will be hell to pay. The radio is on and off, and i don't find it particularly comforting.

[237SJ]

When I was little we lived in a fairly remote place and about 500 feet above sea level. I don`t know whether that has any bearing but when there was a flash of lightening, the phone used to `ting`. I was scared of thunder and found the phone tinging spooky. Did anyone else get that?

[painterman32]

When I was a little boy, (well before the second world war - around 1935, I remember quite clearly I was sitting in the garden playing, suddenly my gran came flying out of the kitchen, and started grabbing the washing off the line and then huge drops of rain began to fall - all of a sudden there was a huge flash of lightening and it hit the tree in the field right next to the garden, that happened to have a cow under it - it earthed itself via the cow and she gave a bellow and fell on her side - the thunder was deafening - poor old Bessie bought it - she had a scorchmark from her horn all the way along her body and down her back leg. They had the 'man from the ministry' come and confirm she'd been killed by lightening - my grandad was really annoyed as she was one of his best milkers after that my gran used to grab what she could (usually me, mum and my sister) and hide under the stairs cupboard whenever there was a storm. I never bother to unplug things - and don't know anybody who does!

[237SJ]

There was a farmer from our village (before my time) who took all his milk churns on the back of his horse and cart to deliver the milk. On the way home a thunderstorm blew up and the metal churns attracted the lightening. They were obviously struck and the horse took him all the way back to the village, dead.

[Coldicote]

Some sad stories here, but it just shows what lightning can do. From childhood I was told never to shelter under a tree in a thunderstorm as it could attract lightning. Pointerman's experience proves the wisdom of that. Scotman's website link gives useful information. Thank you everyone.

[Maydup]

We haven't had a storm here in years and years, I miss them really.

But when we did have a serious one, I did unplug the TV aerial cable. The aerial always seems quite vulnerable and I've heard how it can blow up the TV if strick or even start a fire. Never unplugged anything else.

[beso]

I worked designing a wind turbine for a few years. Lighting is a huge issue in this industry so I do know what I am talking about. You should definitely unplug your modem during thunderstorms.

Direct strikes are extremely destructive. I have seen huge trees turned to splinters by direct strikes. The sap boils and blows them apart. The danger to anyone sheltering greater from the explosion than the lightning itself.

Most lightning damage to electrical devices is caused by voltages induced by ground currents.

A lighting strike is in the order of hundreds of thousands of Amps. This current also flows through the ground to feed the strike and the resistance it encounters flowing through the earth can produce hundreds of volts per metre on the ground.

This is why the feet should be kept together when outside in a storm and you should stay well away from any conductive object. It is imperative that you do not cling onto another person but stand well clear of each other.

Never ever place yourself or any equipment between two conductors that are connected to the ground in different places.

In the case of the computer the two connections are the power ground and the telephone ground (through the modem) which may be separated by kilometres especially in rural areas.

I unplug the modem during storm and have seen a substantial arc jump from the telephone socket to the case of the computer a few inches away. At the time the storm had already passed and the actual lightning strike was so far away that we did not hear the thunder. The ADSL filter on the telephone was destroyed. The modem and probably the at least the Ethernet port in the computer would have been too if it was still plugged in.

Although a surge diverter offers some protection the potential in the lightning is so huge it may exceed the capacity of the diverter. It is much safer to disconnect the modem.

05:21 Wed 29th Jun 2011

[beso]

The television antenna may be grounded through its mounting to the house. It is generally less of a problem on wooden houses but some houses use metal fascia which can be grounded through the stormwater pipes. The bracket may also be braced to a metal roof. Best unplug the antenna. But as Berkshirelad says, don't leave it too late. You would be unlucky to get a strike right at the moment but it certainly would not be pleasant.

It is generally quite safe to leave the devices connected to the power so long as there is no other connection to the ground. However a house on a slab may be a problem. Wooden floors are the best protection.

[beso]

237SJ's story sounds unlikely. It would be very unusual for for the horse to survive a close strike because the ground voltages between its feet.