Lighting kills...

**adrianh** · 02-Dec-13, 10:03 PM

This is also interesting to think about; the guys that do live HV line maintenance. They wear suits that are essentially faraday cages capable of carrying the current. The guy inside is ok because the current flows around him. He gets picked up off the ground by a helicopter and a long insulated cable which insure that the helicopter doesn't get electrocuted. I suspect that when is picked up and lowered to the ground he would have to dangle a cable hitting the ground so as to dissipate the charge to ground so that is cage has the same potential as the ground.

**adrianh** · 02-Dec-13, 10:09 PM

Think about connecting a 300mA 100V transformer to a 12V radio. The radio ain't going to work anymore .

**tec0** · 02-Dec-13, 10:41 PM

First and foremost “I am not expert” Secondly I stand to be corrected otherwise I will probably get someone screaming about details again. So I start with the facts here

The Fatal Current

Strange as it may seem, most fatal electric shocks happen to people who should know better. Here are some electro-medical facts that should make you think twice before taking that last chance.
It's The Current That Kills

Offhand it would seem that a shock of 10,000 volts would be more deadly than 100 volts. But this is not so! Individuals have been electrocuted by appliances using ordinary house currents of 110 volts and by electrical apparatus in industry using as little as 42 volts direct current. The real measure of shock's intensity lies in the amount of current (amperes) forced though the body, and not the voltage. Any electrical device used on a house wiring circuit can, under certain conditions, transmit a fatal current.

While any amount of current over 10 milliamps (0.01 amp) is capable of producing painful to severe shock, currents between 100 and 200 mA (0.1 to 0.2 amp) are lethal. Currents above 200 milliamps (0.2 amp), while producing severe burns and unconsciousness, do not usually cause death if the victim is given immediate attention. Resuscitation, consisting of artificial respiration, will usually revive the victim.

From a practical viewpoint, after a person is knocked out by an electrical shock it is impossible to tell how much current has passed through the vital organs of his body. Artificial respiration must be applied immediately if breathing has stopped.

The Physiological Effects of Electric Shock

The chart shows the physiological effects of various currents. Note that voltage is not a consideration. Although it takes voltage to make current flow, the amount of shock-current will vary, depending on the body resistance between the points of contact.

fatal current

It is also fact that if you have a weak heart that the effects might be worse for you.

**tec0** · 03-Dec-13, 03:34 PM

Now I didn't know half of this...

**tec0** · 03-Dec-13, 04:00 PM

This is scary stuff...

**adrianh** · 03-Dec-13, 06:07 PM

I wonder whether electric fence installer need to have some or other certification. It's amazing that there are so many people working with high voltage equipment yet they do not have the foggiest idea of basic electricity, safety and fault finding. One of the things that I find truly disturbing is the way in which many electricians wire up panels; its all just a mass of crisscrossing wires going from point to point with splice joints anywhere along the length of the wire. No schematic, numbers, markers nothing, just a lot of spaghetti.

**Dave A** · 03-Dec-13, 06:30 PM

Originally Posted by adrianh

I wonder whether electric fence installer need to have some or other certification.

They do now - since 1st October 2012. Implementation has been a right royal stuff-up though.

**tec0** · 12-Dec-13, 10:08 PM

I just thought I asked.

How many laptop computers did any of you lose due to lighting?

**adrianh** · 12-Dec-13, 10:17 PM

None. I did lose a dial up modem once...long ago.

**tec0** · 12-Dec-13, 10:23 PM

Originally Posted by adrianh

None. I did lose a dial up modem once...long ago.

I have been in IT all my life. Did you know I cannot recall a single notebook ever being damage due to lighting. Not one... Do you know how many desktop computers I have processed due to lighting per year. Well over a thousand computers in total. That makes it a minimum of just over a hundred desktop computers damaged by lighting in a single year...