You should always turn your computer and router off during thunder storms
Computers can be sensitive to power line interference, and thunder storms can cause power voltage spikes, brown-outs and melt-downs
We have witnessed several instances where computers and modems have been damaged, by storm activity - including melted circuit boards and internal fires.
Easykey recommends that you switch off and unplug from the electrical mains. Also unplug your broadband router from the mains and from the telephone line.
Voltage spikes are transitory, higher than normal line voltage fluctuations, which can be caused by thunder storms, and by just about any electrical equipment you use in the house, particularly high current devices, such as refrigerators, generators, electric tools, heaters and pumps. These devices can cause large electrical spikes on the mains power line, as they are switched on and off.
If you wish to protect your computer from these sources of damage, buy and install a surge/spike suppressor. We can supply one if you wish.
However a surge-protector DOES NOT PROTECT YOUR EQUIPMENT from a direct lightning strike.
Brown-outs are lower than normal line voltages, causing power starvation to the electrical device. In other words, your computer doesn't get enough power, and this can damage it. Brown-outs are not generally transitory but can last from a few seconds to minutes. You can buy specialized power supplies that monitor the line voltage fluctuations, and when the power goes off, or has a serious fluctuation, the power supply kicks in and supplies power to the computer via a battery backup system. This sort of device is much more expensive, and is generally used by larger businesses, corporations and government departments to protect their important computers, and computer systems from damage.
A meltdown is a direct hit by a lightning strike, if this happens because of the large voltages and currents involved, normal suppressors won't do much, but there are a couple of things that will help a great deal. Turn your computer off, and also disconnect it from the wall socket and disconnect the router from the telephone line and electricity socket. (I do this whenever we have a thunder storm.) Power surges and voltage spikes can also come through the telephone line during storm activity! That's why phone companies have warnings in their literature not to use the phone during storms. This advice applies to all sensitive electrical equipment not just computers. Check your insurance policy as to what cover you are given for lightning damage. A lot of insurance companies limit your cover calling it an 'act of God'.
What if the computer is not plugged in?
Theoretically you might be safe to use someone else's WiFi (e.g. a cafe) AND using a device not plugged into the mains (e.g. Tablet, Phone, Laptop on battery)