Well, it's the rainy season now in Central Mexico, and that means pretty ferocious electrical storms at night. It is not unusual for a storm to last several hours, with forty, fifty, or more lightning flashes per minute, and water running down the streets toward the lake so fast and deep that it is dangerous to try to walk across it.

The great majority (95% plus ) of the lightning flashes are cloud to cloud, but that still leaves two or three ground strikes per minute as the storm rolls through. These storms will happen several times a week for the next three months. Then, we might go eight months without measurable rainfall until the next rainy season starts.

Rainy season by nearly unanimous opinion is the absolutely best time of year. The storms come only at night, and everything is lush and green, and the temperature drops from the mid to high eighties during the day down into the sixties at night.

However... those lightning strikes have me concerned. When the storm comes in, what should I do to protect my electronics? Everything of any value is on surge protectors. The computers and peripherals are on APC Uninterruptible Power Supplies. I power everything down except the refrigerator when I hear the thunder starting. Is that enough?

Or should I take it a step further and open the circuit breakers on the expensive stuff? That would give an extra layer of protection to the refrigerator, the laser printer, and the air conditioners.

Would turning the UPS's OFF accomplish anything useful? Of course, if I open the breaker for the computer circuit, the UPS's have to be turned off or they'll start beeping.

Perhaps none of it would be enough if I got a direct hit on the transformer that is less than 50 feet from my house. A lightning strike can be a Billion volts at more than 100,000 amperes. That kind of power wouldn't even slow down for an open breaker.

Am I just living a lottery here?

tanstaafl.

A direct lightning hit on your nearby utility transformer will indeed create a surge within the connected buildings. Some of the surge will be absorbed by the other connected equipment (which may die in the process) including the equipment and electrical panels of all your neighbors.

Effectively you just need your equipment to be well enough isolated that the energy which actually arrives at your electrical system is unable to do damage to your equipment.

Unplugged (not just switched off, but actually unplugged) equipment I would consider to be unlikely to suffer damage. The catch is that the unplugged equipment must also be disconnected from other things that are themselves still plugged in (even if those other things are switched off).

For an unplugged computer, that means also unplugging the printer, the Internet modem and router, everything else that has a wire connected to the computer. If all the connected equipment is on the same power bar, unplugging the power bar cord from the wall outlet should isolate everything in one motion,

The Internet modem has the additional risk of a surge traveling through the telecom cable so it should either be disconnected from the telecom wire or completely disconnected from the network (all Ethernet cables pulled out) and from the computer(s).

You are correct that a direct lightning hit could traverse a turned off circuit breaker, but it does improve the odds in your favor.

One crazy aspect is that lightning can raise the voltage potential of the actual earth (the dirt) by thousands of volts. So the grounded 'protection' of the building electrical system can become a vector for energy to attack equipment. This is one way that unplugged differs from turned off, unplugged also isolates the equipment from ground surges.

Surge protectors are a subject all on their own. My feeling is the majority of consumer surge products, power bars or plug in modules have very limited utility.

Often the surge absorbing electronic devices inside can fatigue or fail with no outward signs that the surge capability no longer exists. Some of these products may have LED indicators, but the indicator may just be for 'entertainment' and not actually an indication of ongoing protection.

There are large capacity surge absorption devices that typically install within the main electrical panel. These tend to have more substantial energy absorbing capacity. They also cost more.

Do you know anyone in the area who has actually had any damage done by these lightning strikes?

If you're really worried, have these installed in your breaker panel:

Linky

That'll take care of all incoming spikes & surges, has real indicators for it's condition, and has contacts to let you know when it's failed.

Between this and putting a transient voltage surge device on anything higher than your roof (antenna, etc...), you should be good.

As annoying (to me, at least) as those LED indicators are, they do serve a real purpose.

The surge suppression devices are typically varistors (or similar devices), which have the unfortunate property of short-circuiting when they fail. To prevent this from causing a fire and destroying one's home, the circuit must include a fuse or breaker of some kind, which will trip when the short-circuit eventually occurs. For the fused variety, usually the protected circuit continues to operate, just without any further surge protection.

The LEDs are fed from the fused portion, so when they stop working, you then know the surge suppression is b0rked.

There are a variety of "whole home" surge suppressors. When I was having an emergency natural-gas generator installed, they upsold me on one of these things. I have no idea how well it will work, but the $75,000 equipment warranty speaks more to me than any other technical specifications. (Okay, there was that one time my old house took a lightning strike and I tried, and failed, to claim the damage from my stereo gear that was plugged into a Monster power strip. But then we all know that Monster is evil.)

That said, none of this will help me if my house takes a direct lightning strike, or if there's somehow a massive voltage influx through the phone or CATV wiring.

Back to the original post, if I were living in a region with regularly scheduled lightning storms like this, I'd be tempted to disconnect the expensive stuff, as you are, but then if it's raining like hell, I'm far more likely to be inside using my nice computer than outside enjoying the torrential rains and whatnot. Certainly, without a doubt, I'd want to have an offsite backup strategy.

Yeah - the telco lines matter, too.

At our farm house in the mountains, we had lightning come in over the phone line some years ago. It melted the NID, fried the cordless phone and base, and blew the phone's wall-wart apart - sending the plastic cover across the room. The surge protector died in reverse. Fortunately, the circuit breaker stopped it there.

The house itself has several lightning rods, and fortunately no direct hits that I'm aware of.

Yes... and no.

A friend living two blocks away has had many power problems, destroying at one time or another just about everything in his house that uses electricity, despite a heavy-duty whole-house surge protection system.

He is on a different power main than I am, and thinks that his problems are related to a bad transformer. His many complaints to the power company have proven to be fruitless.

The power main that I am on is relatively new, about three years old. A 23,000 volt power line runs up my street, less than four feet from the side of my house, to a transformer about 50 feet away. My house painter won't paint the top floor of that wall, too dangerous. I am first in line for receiving power from the transformer.

The power pole with the transformer is not an obvious target for lightning. It is nestled up against the base of the mountain and there are plenty of objects higher in the air than the top of that pole. The highest part of my house is probably 20 feet lower.

In all the time I have been here, I have not had any electrical problems. By Mexican standards, my electrical system is preposterously overbuilt. On the fourth floor alone (my part of the house) there are 12 circuit breakers controlling output in what is essentially three rooms and a deck. A Mexican lady in my kayak club was amazed to hear that, she thought her home was well protected having four breakers for the entire house.

Attached are some photos showing the transformer, the wires by my house, and a picture showing the lineman when the new lines were being installed. I think I posted that picture here once before.

tanstaafl.

And I'm freaky about working with 120VAC live wires...

I've just got all my stuff on APC UPS's. A direct strike is so rare, if it happens I'll just replace stuff. I do physically unplug my laptop, but none of my other electronics are worth more than $300.

My theory, as well -> "I needed a new TV anyway."

Although our one house had a direct hit on the phone lime. Blew the outside phone box cover about 100 feet from the house and melted most of the phone lines in the house. If was real close to starting a fire.

Other than that no big loss since no one uses land lines anymore.

No se ahoga en un vaso de agua

Hey!

That's because you think your electronics consist of your laptop and your TV set. But just about all your expensive stuff is electrical, if not electronic. Things like your refrigerator, your washer and dryer, your microwave oven, kitchen appliances, telephones, air conditioner(s), ceiling fans, maybe a pump, a water heater, even light bulbs can add up if you are using LEDs or compact fluorescents. Just sitting at my computer hutch, I can add up over $4,500 worth of stuff that I can reach out and touch without getting out of my chair, stuff that would be absolutely destroyed by an extreme power surge. Add another couple thousand dollars for things that are only intermittently connected to chargers -- iphone, camera, shaver, ipad, Kindle(s), etc, and don't forget the TV set and DVD player. Then, if I scoot my chair over about five feet, my wife's computer hutch holds another two or three thousand dollars worth. [My wife and I each have our own computer systems because of our difference of religion: She's Macintosh, I'm Windows.]

More than once I have heard horror stories about electric company linemen working on the power lines. They make a mistake and send 440 volts down the lines to the local houses that are supposed to getting 220V, and the destruction is awesome, costing the electric company hundreds of thousands of dollars in compensation up and down the neighborhood.

I dunno. Perhaps the fact that in over five years here I have not had a problem is an indication that I don't need to worry. Or, perhaps I have just been lucky.

tanstaafl.

Man, mixed marriages are so tough.

No actually I meant that none of my junk is worth more than $300. Bought all of my appliances "used" for cheap (found on various internet postings from around Guadalajara.) All I have that stays plugged in is a washer, dryer and fridge and cheap microwave. Oven and water heater belong to the homeowner, but they are gas anyway.

My [non-judgemental] philosophy is that these things are for utility more than the bells and whistles. Not to mention these items that lose half or more of their value within a year or two. I always buy used appliances and then keep them repaired myself, occasionally with the help of Youtube videos. If something totally dies or gets fried, no big deal, I can easily replace it out of savings with something equally inexpensive.