Is Your Home Safe From Lightning Stikes?

[brahmburgers]

just a reminder: about lightning strikes

Last night, lightning struck - literally! It knocked out a football sized chunk of asbestos roof panel in my storage shed - on its way to knocking a fist-sized chunk of masonry out of a wall where some electrical wires were. In a millisecond, it tripped all circuit breakers in four neighboring houses and burst a flourescent bulb in one.

Three reasons I'm writing this:

1. make sure all your electric is fused.

2. consider getting a lightning rod installed. I had things grounded (or 'earthed' for Brits) - but will now install a lightning rod.

3. back up your important computer files on to disk. One of my neighbors lost his hard drive, even though his computer was not on at the time. I didn't suffer damage to my computer - I think it's because it was grounded with a heavy wire.

[toonarmygeorge]

Just a reminder for when you carry out repairs to your roof. Mask up, so you don't get any of that asbestos fibres in your lungs. Nasty stuff that asbestos.

Caring member

[TBWG]

just a reminder: about lightning strikes

Last night, lightning struck - literally! It knocked out a football sized chunk of asbestos roof panel in my storage shed - on its way to knocking a fist-sized chunk of masonry out of a wall where some electrical wires were. In a millisecond, it tripped all circuit breakers in four neighboring houses and burst a flourescent bulb in one.

Three reasons I'm writing this:

1. make sure all your electric is fused.

2. consider getting a lightning rod installed. I had things grounded (or 'earthed' for Brits) - but will now install a lightning rod.

3. back up your important computer files on to disk. One of my neighbors lost his hard drive, even though his computer was not on at the time. I didn't suffer damage to my computer - I think it's because it was grounded with a heavy wire.

Hi brahmburgers

Trust you are OK.

I have thought about lightning strikes and had lightning conductors put on the roof.

But I do also have a whopping great stainless steel water tank mounted on the roof and feel that this is an invite to get a hit!

Is it a big risk? has anyone experienced a strike to their tank? What where the consequences?

But hey brahmburgers they say lightning never strikes twice, but don't push your luck

TBWG

[thedi]

... they say lightning never strikes twice, but don't push your luck

'They' are wrong. Lightnings have a tendency to come down at same places again and again. There s a very famous place in Switzerland (Monte Bre, near Lugano) where lightnings come down very regularly. Some people go to Lugano to watch this spectacle from a save distance.

The biggest problem of a lightning is the high voltage that hits at the ground at one place. It will distribute in all directions, always following the best conductor.

If you stand close to a point where a lightning hits the ground, the electric charge difference between your feet may be several thousand volts. If you would stand on a metal plate, the current would pass through the metal plate and you would feel nothing of it. If, on the other hand, you would stand on a isolator, the current would rather flow through your body and kill you.

A computer may be damaged by the fields. This may happen with or without proper grounding. A save protection would be a metal cage with the computer not connected to any cable that leads outside of the cage. The cage should be grounded.

Proper grounding of your house should reduce the risk of a fire and lead the high electricity to the ground without using you or your house as an easy way. If your house is hit by a lightning, your TV, refrigerator etc will most probably be gone. A fuse may not react in the short time.

Regards Thedi

[Jai Dee]

Topic moved to housing forum - not really farming related.

/Moved.

[brahmburgers]

update : upon closer inspection: the storage shed got pummeled in 3 seperate spots, about 1.5 meters apart. In only one spot was there some wire on the other side of the masonry wall (it disintigrated). All 3 spots look as though someone fired a high powered rifle with uranium tipped bullets - the fist-sized holes go right through the 4 inch thick wall.

collateral damage: the farang across the street lost his laptop even though it wasn't on. the picture on his giant TV became about 40% smaller. A few little electronic things got zapped in my house. Methinks that anything that had a stand-by provision (red LED light) is susceptable to damage. Lightning acts in odd ways. Some electrical things got spared, some got a current surge even when off. 3 out of 4 HW on demand units got zapped - costing average 550 baht per unit to fix. I had previously put heavy ground wires on some things, and they were spared.

Worst was the submersible pump that provides waster for four homes. It's a 1 hp with a thermal switch - which should have been enough of a protection. It wasn't. The control box, the pump motor and even the float switch all got it - costing about 15,000 baht to repair. If I hadn't shopped around and/or had a professional do the work, it would have cost double that amount (I installed water systems in California in a former life). I just now put a 40 amp breaker on the pump control box.

one more thing: the lightning voltage is so intense that it seemed to have bypassed (jumped) some breakers and even some switches that were off at the time. In other words, some lights and appliances that were off and were protected by breakers that tripped - were damaged.

I guess you can't be too careful, in the sense of heavily grounding all things electrical.

[Khun Jean]

I thought lighting went from the ground UP.

[Naam]

I thought lighting went from the ground UP.

only on alien planets... like mine.

[percy2]

collateral damage: the farang across the street lost his laptop even though it wasn't on. the picture on his giant TV became about 40% smaller. A few little electronic things got zapped in my house. Methinks that anything that had a stand-by provision (red LED light) is susceptable to damage. Lightning acts in odd ways. Some electrical things got spared, some got a current surge even when off. 3 out of 4 HW on demand units got zapped - costing average 550 baht per unit to fix. I had previously put heavy ground wires on some things, and they were spared.

one more thing: the lightning voltage is so intense that it seemed to have bypassed (jumped) some breakers and even some switches that were off at the time. In other words, some lights and appliances that were off and were protected by breakers that tripped - were damaged.

I guess you can't be too careful, in the sense of heavily grounding all things electrical.

Anything that is plugged in/connected to the electrical system can be fried by lightening.

Unplug/disconnect anything you can't afford to lose.

Cheers

[dsfbrit]

Anything that is plugged in/connected to the electrical system can be fried by lightening.

Unplug/disconnect anything you can't afford to lose.

Cheers

This is the best and most simple advice in my opinion. Include aerials as well, in the UK I went away on holiday, unplugged everything, but forgot the aerial on the downstairs TV - the neighbours said there had been a massive lightning storm whilst we were away and the repair guy said several neighbours sets had also been damaged.

In Thailand last year, the house was struck and the burglar alarm was damaged as we had a telephone line going into it - to call the security firm if the house was burgled when we were away.

I have also fitted line surge protection plugs and power-backup/ line filters to my computer etc... Dont know how much use they will be if the house is hit when my computer is switched on though?

[quiksilva]

I was thinkin the same dsfbrit, I use surge protectors on any electrical equipment I care about (namely computer, TV and home theatre etc) however I dont really know if it will help but I hope it will.

I'll have to look into lightening rods, a friend of mine runs a company called Risk Protection and Im pretty sure they carry these items.

[jackr]

Anything that is plugged in/connected to the electrical system can be fried by lightening.

Unplug/disconnect anything you can't afford to lose.

Cheers

Cock on

Install a lightning rod and if you hear thunder (lightning exploding air molecules ) still unplug everything and wait for the storm to bog off. You can still use your laptop on battery and hack into the neighbours' wireless router for your internet until it passes. You may still lose any earth-monitoring device but at least your appliances will be ok. If you want to be really anal, remove the tails out the bottom of your Safe-T-Cut, but knocking the thing off beforehand of course

[AlbertTatlockDeceased]

For my penny's worth, you need lightening rods on the roof (i believe they need to be no more than 12 feet apart - i.e. if you have 36 foot roof or more, then you will need 3)

Use heavy guage copper conductor insulated from the roof to link the rods, the conductors should be insulated in conduit (remove any insulation from the conductors i.e the pvc coating if using copper cable(The conductor is not cheap at about 5000/100m) where they descend from the roof.

They should have NO SHARP bends, keep smooth rounded turns.

The conductors should (there really needs to be two) descend from the roof at diagonally opositte corners from the roof.

They should be bolted to grounding rods copper is good but steel wll do almost as well. There shold be 3 of these (3m long) driven into the ground approximately 1 metre apart in a triangular pattern, linked together and covered over with earth.

A second set of 3 of these at the other diaganol corner in the same pattern.

The final item is a surge protector for the consumer unit/fuse box, it needs to be right where the main electric joins the house, individual surge protectors will not handle the massive voltages from a lightening strike. The current induced in your internal cabling is enough to damage eqipment NEAR the cables - disconnection is by no means a definate safety catch.

[brahmburgers]

lots of good responses. The point I was making, was that even items that were off at the time of the strike - were damaged.

Either the charged field was so intense, or the mega voltage momentarily jumped closed switches and tripped breakers. it only takes a tiny fraction of a second.

and standby mode counts as ON. Most big ticket electronic items stay on in stand-by and we take it for granted.

couple other effects of the 'sheet-lightning' strike: car alarm went off. It's electric triggered, not pressure-triggered. you would think a dry vehicle in a carport wouldn't be a conductor.

A neighbor, 100 meters away had their Electric Company installed meter box catch fire. completely fried the meter and the connecting cables.

I wonder what electric storms are like on Jupiter, where just the 'eternal storm' red spot alone could swallow the earth.

[elkangorito]

To find out the basics of lightning protection, click on this web address;

http://www.crossy.co.uk/wiring/lightning.html

This particular article, like most of the other articles on this website, was written by me.

[GuestHouse]

Ligtning protection aims to do two things - The elctrical protection that Electropro has referenced and structural protetection (of the form that you see on a church spire).

Some basic safety points to note.

The lightning protoctors that Electropro mentions are exteremely effective at protecting the cicuits to which they are applied, but it is unlikely that they are applied to all circuits in the house/building - Telephone lines and Cable TV circuits are two that you may not be able to protect.

So don't use the phone and turn the TV off. I wouldn't bother disconnecting, if for example you are sharing a Cable TV system, somebody else's TV is going to be connected hence providing a (relatively low) path to earth - If lighting hits the circuit you disconnected cable will now have an extremely high voltage looking for a way out - better to go through your TV than flash over in the room. (I have seen a case where this happened).

Mobile phones are a problem too. Using a mobile phone causes the air around the antena to ionize (a magnet for lightning) so no mobile phones out of doors in a lightning storm.

Building Protection.

Lightning rods work by conducting the strike safely to ground (obvious I know) but they do not provide as wide a protection as many believe.

The spike on top of a building/water tower provides protection to a the area beneath in a 'cone' with sides angled to the ground at about 15 degrees. This is why you need several spikes along a roof.

The higher up they are the better, certainly if I had a water tank on a roof I would put a spike up, perhaps two or three meters above the tank.

The spike should be a copper rod of about 10 mm diameter and should be pointed at the sky end. (I've seen lightening spikes with gold and even one with a platinum tip - this to ensure a better spike to air connection, but I'm not convinced it is necessary to go to that length).

The spike should be connected directly to ground, in the shortest possible run by means of a copper cable that is at least 35 mm square area (70mm2) would be better.

To make the connection to earth you can buy copper earth spikes, but I think a far better idea is to bury the 'earth end' of the cable directly in the ground.

Simply dig a trench or hole that is deap enough to reach the 'permenantly wet' sub soil and then make a loop of the copper cable about 3 meters diameter (more if you can).

If you are building a house or later find you need to build over the ground cable, then don't put the cable under the foundations, because the ground there will dry out.

A note on copper ground rods. I've found a lot of 'copper rods' being sold in Thailand are nothing of the sort - and are actually copper plated steel rods - These are useless, so do check you are getting real copper if you are buying ground rods (and spikes).

[brahmburgers]

question:

what if lightning makes a direct strike on a lightning rod? Wouldn't it destroy at least parts of the copper wire leading to the ground (whether insulated or not)? and if so, would it not also damage whatever the rod is attached to (side of building, etc.)?

I vaguely recall that a bolt of lighning is about 1 inch in diameter - that sould seem like a whole heck of copper-melting voltage.

I wouldn't want to be standing out in the rain flying a kite with a key on the string - leading to ......leading to a jar of water? Is that what one of America's fouding fathers did. Speaking of 'founding father' I believe Ben Franklin had dozens of kids out of wedlock.

[elkangorito]

what if lightning makes a direct strike on a lightning rod? Wouldn't it destroy at least parts of the copper wire leading to the ground (whether insulated or not)? and if so, would it not also damage whatever the rod is attached to (side of building, etc.)?

I vaguely recall that a bolt of lighning is about 1 inch in diameter - that sould seem like a whole heck of copper-melting voltage.

I wouldn't want to be standing out in the rain flying a kite with a key on the string - leading to ......leading to a jar of water? Is that what one of America's fouding fathers did. Speaking of 'founding father' I believe Ben Franklin had dozens of kids out of wedlock.

Answers to your questions.

1. There are 2 kinds of lightning strikes - Primary & Secondary. A Primary strike is a direct strike. i.e. a bolt of lightning hits something. A Secondary strike is when things surrounding the area of the direct strike are also highly charged & therefore affected by the strike.

Usually, a direct strike has devastating effects on the things it hits, like melting metal etc. This is why most modern buildings DO NOT use lightning rods. Instead, they use a metal matrix of busbar (usually tinned copper busbar) that surrounds the outside of the building & internal metal structures, to carry the charge to a seperate earth point. I have actually installed such systems in/on some government buildings in Sydney (Australia).

2. Bolts of lightning can be much much larger than an inch in diameter.

3. It is unlikely that Ben Franklins' kite was directly struck by a bolt of lightning. It is more likely that he witnessed/experienced the effects of a Secondary strike.

The only place you will see lightning rods used is in an electrical high voltage switchyard. Generally, these yards are quite small in area & many rods are used. The rods are usually towers of galvanised metal that are significantly higher than the highest piece of equipment installed in the switchyard.

For domestic purposes, lightning rods are not recommended. Do you really want to attract lightning to your house?

The most recommended protection is the installation of a MOV (Metal Oxide Varistor). These are not cheap but will protect the electrical system (and connected appliances) from lightning strikes.

[GuestHouse]

One of the OP's buildings has already been struck by lightning, hence hardly attracting lightning, rather the lightning has already struck once.

I did some reading up on this today, we have a corporate Lightning Protection standard based largely on BS6651 and API2003.

The list of factors that give rise to an increased likelihood of a lightning strike is quite long, but right up there is ground condition - this explains why some areas are suscpetable to lightning strikes more than others where the hight of trees and structures is similar.

So if you have a building that has been hit once, the chances are it is goig to be hit again.

Certainly under normal circumstances I wouldn't go putting a lightning conductor on a house, but if the house has already got steel structures ( a water tank and frame) poking into the air then a lightning conductor might very well be a good idea.

I think we should also note that many houses have lightning conductors fitted - they are alternatively referred to as 'TV Arials'.

As for lightning conductors melting. I've never seen that and I've inspected quite a few installations that have been in place for many years.

[chownah]

Mobile phones are a problem too. Using a mobile phone causes the air around the antena to ionize (a magnet for lightning) so no mobile phones out of doors in a lightning storm.

I don't know if mobile phones are a problem or not. I don't think that the air around the antenna of a mobile phone is ionized. The electromagnetic waves emitted by mobile phones is not classified as "ionizing radiation" from what I can remember of high school physics.

Chownah

[chownah]

3. It is unlikely that Ben Franklins' kite was directly struck by a bolt of lightning. It is more likely that he witnessed/experienced the effects of a Secondary strike.

From what I have heard about his experiment the kite was not struck by lightning at all. From what I read the kite was up in an area where it accumulated static charge until the potential difference between between the kite and the ground side of the leyden jar was enough for a spark to jump across a small gap. I suppose that you could call the small spark "lightning" but really that would be incorrect by normal definitions of lightning.

Chownah

[Tony Clifton]

Just a reminder for when you carry out repairs to your roof. Mask up, so you don't get any of that asbestos fibres in your lungs. Nasty stuff that asbestos.

Caring member

And once done, PAINT THE STUFF!

Our neighbour has installed a TV antenna right between both our houses, let the lightning go for his tv.

[bloody tiger]

I witnessed a lightning strike to my watertank about a month ago whilst i was in the yard....awesome sight BTW.....when building I installed good quality lightning rods, good thick heavily insulated cable and 8 foot earthing poles, one set each for my home and water tank.....I probably could of just installed one on the water tank as it is a few feet higher than the house and only about 15 metres away, but felt more secure with one on both. For those who may not know what a lightning rod does, it is effectively an electrical cct from above your roof line to the earth which means the lightning will bypass your house by travelling directly from the lightning rod to earth via the thick insulated cable.

Under the water tank I have an attatched outside kitchen and laundry area as well as water pumps....around 8 appliances were in use or plugged in at the time....no damage to any of them...so I feel the lightning rods have already payed for themselves.

From memory, I think the materials cost me about 13K baht and installation about 1.5K.

During thunderstorms I feel safe enough NOT to disconnect electrical appliances but I do disconnect the telephone connection to my PC as the telephone line is not protected by my lightning rods (ie. a lightning strike to a telephone line/box outside my home)

Incidentally, surge protectors, safety cuts, residual CB's etc are all great equipment to protect against power surges/shortcct's etc, but have no effect against the huge surge of a lightning strike. The only true way to protect is using a ligtning rod. Unplugging everthing is gr8 for yr appliances but you still run the risk of frying your electrical system.

Condo owners should check that the building has one (or more) installed.

Hope this was of some use,

Chok Dee na krub

[jubby]

Interesting topic, takes my mind off all the VISA woes ;-)

I have a typical thai style bungalow (cheap construction) , Half has a wooden roof and half has a steel roof which is grounded as its attatched to the steel running through the concrete posts, doesn't this afford some protection , kind of like a cage ? I know the electrical equipment isn't protected but I'm more concerned about the safety of the family.

just slightly of topic, but someone mentioned asbestos roof tiles, Do those tiles have a lot of aspestos in them ? I was told they only have a bit in them, they certainly look 100% aspestos to me, but I would have thought aspestos wasn't used anymore, even in Thailand.

[Thaddeus]

For domestic purposes, lightning rods are not recommended. Do you really want to attract lightning to your house?

Agreed.

I have been on the receiving end of two secondary strikes in the past year or so and I see absolutely no need to advance my status to a primary target by sticking a metal pole on my roof.

[realthaideal]

So when you goto the construction materials store, how do you go about asking for a lightning rod in Thai ? Do they have such a thing ?

[realthaideal]

So when you goto the construction materials store, how do you go about asking for a lightning rod in Thai ? Do they have such a thing ?

[elkangorito]

So when you goto the construction materials store, how do you go about asking for a lightning rod in Thai ? Do they have such a thing ?

Answering your first question - I don't know.

Answering your second question - no.

You could always go and stand on the roof during a storm but make sure you wear a hat.

[pkrv]

Try this link it is interesting though heavy duty.

http://en.wikipedia.org/wiki/Lightning_rod

[elkangorito]

Ahhh yes! Good ol' wikipedia...the epitome of accuracy.

Here's a 'real' document about lightning protection. Please note sections 3 & 6.

In short, don't even think about plonking a lump of metal on your roof, which is connected to another lump of metal to the ground unless you really want to go to the trouble & do it right. By not doing it correctly, you could, in fact, cause more problems. Lightning protection is not a simple thing.