Does it provide any protection for laptops, appliances, etc. if you merely turn off an extension cord during a lightning storm (but don’t unplug it), or does only unplugging ensure safety?
Unplugging is better than turning off the power strip. But if there’s a strike bad enough to jump the switch of a decent power strip, there’s going to a lot of other things to worry about.
Note that some strips are better than others. Forget those no name ones entirely. Even some well known brands like CyberPower aren’t that great. Go with a brand like Tripp Lite.
My rule of thumb: routine thunderstorm just throw switches. A really big storm means time to unplug.
Anecdata point. Bolt hit transformer/pole 50’ outside my house years back. Three foot extension/power outlet with “surge” protection fried. My power amplifier triac (used to start amplifier when preamp turned on) and associated soft start circuitry also took a bullet but saved the rest of the amp. Some rewiring to a plain on/off switch kept the amp functional. Refrigerator took a bigger hit, compressor motor (maybe capacitor) died. A cooler and ice bags saved the food. Land line phone was dead as was the phone connection box on the pole.
Unplug.
That lightening has already jumped thru miles of air between the clouds in the sky & the earth. A centimeter or less inside a little switch isn’t going to stop it. Even unplugging the cord and moving it 10 feet away from the outlet won’t swtop the lightening if that is the way it goes.
So it really doesn’t make much difference.
But it can’t hurt, either. Many of us could use the exercise.
I recall a well documented strike detailed in one safety class we attended. It was at an Army base and the entire path of the strike was evidenced. I am paraphrasing as this was a long time ago but the lightning hit a power line, traveled to a building, shot through the wall and hit the plumbing, went underground to another building where it emerged again, flew through the air and hit a metal bed frame where it killed someone. The big surprise was that even after it was underground it did not stop.
Dennis
Unplugging definitely makes a difference. What you’re trying to protect against when you turn off or unplug devices is the surge caused by the lightning hitting the electrical system. That surge has so many better paths to chose from than jumping ten feet to take a detour around your appliance.
Unless of course what you’re unplugging is independently connected straight to ground, but how often does that happen.
Of course, if the plug is earthed, that may well be the point. 