Electronics in apartment getting zapped by lightning (need answer fast)

Factual Questions
1

So we are currently in the middle of a rather ferocious lightning storm here in Austin - strongest one I’ve seen here ever, in fact.

Being a layman on all things electrical, I could use help:

  1. Power flickered on and off 4-5 times (across the whole apartment) in just the span of a few minutes. Which electrical component specifically was getting turned on and off and on and off?

  2. Which big unprotected household appliances (stove, fridge, washer, dishwasher, dryer) are likeliest to have been harmed?

  3. Is it true that surge-protector power cords actually DON’T do much to protect appliances like laptops and TVs?

  4. Would the Freon coils in a fridge or HVAC get harmed by the lightning electric surge, or is that too remote and unrelated to cause a Freon leak?

2
  1. Google “Automatic recloser”
  2. None.
  3. Yes. At least not from a direct lighting strike. But, they can’t hurt.
  4. You have a very vivid imagination.
3

wot 'e said. if your power just flickers (e.g. lights dim and electronics reset) then it might just be a “brown-out” condition; maybe something contacting the power lines is diverting enough current to make your voltage sag. if it cuts out completely, then comes back a short time later, it’s an automatic recloser.

for 2, the electronics (if any) are likely running off their own internal switch-mode power supplies (SMPSs,) which are reasonably tolerant of voltage sags and (minor) spikes. for 3), they can clamp an over-voltage condition to a point, but most of them depend on metal oxide varistors (MOVs) which degrade with age. it’s possible, if a cheap surge protector is more than several years old, it’s no longer offering any protection at all. But again, they only protect against voltage spikes on the incoming power lines. They will not protect anything against a direct strike; that bolt of lightning just jumped through miles of air (an insulator.) it’s not going to be stopped by a cheap power strip. if you suffer a direct strike, you have bigger things to worry about such as your building burning down.
as for 4), the refrigerant circuit in your fridge and A/C is made up of copper and aluminum tubing; the only way lightning could harm it is via a direct strike blowing a hole in it. but then again, if that happens it’s going to damage a whole hell of a lot more.

4

For number 1, it could be a lightning strike miles away disturbing the electrical ground near the strike. If you’re that worried, simply unplug everything during the storm. The refrigerator and freezer content, if filled to typical capacity and left closed, will be fine for that length of time.

5
  1. Power lines have circuit breakers of sorts, just like your home. The problem is that when you blow a breaker at home, you just have to go to wherever your breaker box is located and switch it back on. On a power line, that breaker might be several miles down a particular power line branch, so it’s not exactly quick and easy for the power company lineman to get to it to flip it back on. As a result, when power line breakers trip, they have what is called an “automatic recloser” attached to them. You can think of this as a mechanism that automatically switches the breaker back on.

Reclosers are programmable, but they are typically programmed to try turning the power back on a couple of times fairly quickly, then once more after a longer period of time (maybe 30 seconds to a couple of minutes), and then they give up. If they couldn’t keep the power on by then, a lineman has to go out and actually figure out what the problem was.

Reclosers are really good at switching the power back on after the protective devices have detected a fault, especially when the most common faults are from things like lightning or tree branches blowing into power lines and shorting them out.

  1. The working parts of appliances, like the compressor motor in a fridge or the heating element or motor in an electric dryer, are all pretty rugged, just because they are simple. The most likely thing to be damaged in modern appliances is the microprocessor-controlled circuitry that operates the control panel. If your appliances are older or cheaper and have simple mechanical controls, they are fairly rugged.

  2. There are surge protector and there are surge protectors. They are definitely not all made equal. The cheapies will have possibly a single metal oxide varistor (MOV). Better ones will have MOVs between each of the three wires (hot, neutral, and safety ground) and may have multiple MOVs on each. The things to look at for a surge protector are the joule rating (the higher the better), the clamping voltage (the lower the better), and the amp rating (the higher the better). Surge protectors don’t protect you from brownouts, only from surges.

A typical cheapie surge protector might be rated at a couple hundred joules. A better one will be over a thousand. A whole house surge protector (the type that requires an electrician to install), if it’s a decent one, should be tens of thousands of joules. To put it in perspective, a typical lightning bolt has a few billion joules of energy in it. No simple surge protector you can buy can protect you from a direct lightning strike. But a lot of stuff isn’t damaged by a direct strike, but instead from surges that travel long distances through the ground or through power wires. By the time the surge reaches your house, it will be significantly attenuated, to the point where even a cheapie surge protector can be quite helpful.

Of course, a surge protector with better ratings will help you more.

It is possible to make a building pretty much lightning-proof, but it requires things like Faraday cages, Ufer grounds, halo grounds, and other stuff that would cost quite a bit more than what the average home-owner could ever hope to afford. You can google those terms if you want the gory details.

  1. A direct lightning strike can punch holes through metal. Anything else isn’t going to do diddley-squat to your refrigerator’s coolant lines. A surge will completely fry the compressor long before it will damage your coolant lines.

A couple of anecdotes -

I worked in a building many years ago that was hit by lightning. The lightning took out the phone lines, but the only computer equipment that was inside the building that was damaged was the stuff that was on power strips with no surge protection at all. All of the equipment on surge protectors was unharmed. YMMV.

When I was in college, a friend of mine lived in a trailer park. One night, lightning hit the pole right behind his trailer. He happened to have rental insurance, and they paid for everything, but they didn’t want the damaged equipment. So, being electrical engineering students, we thought we could fix his stereo since it was probably just some minor damage to the power supply portion of the circuitry. The outside of the stereo was completely undamaged. We opened up the case, and found that a good chunk of the circuit board inside was just gone - vaporized. As for the remainder of the circuit board, it was charred all over the place, and most of the solder that had once been on the circuit board was now splattered all over the inside of the case. We were absolutely amazed at how much damage the lightning was able to do while not harming the outside of the stereo at all. Needless to say, we didn’t bother trying to fix it.

Lightning is very unpredictable.

6

OK, so an even weirder thing has happened:
Prior to today’s lightning storm, my laptop has always averaged internal temperatures ranging from 50-80 Celsius, as measured by the CoreTemp app. This has been the case for around a year.

After today’s power knockouts, my laptop now averages only 30-50 Celsius even when doing activities that would normally send it shooting up to 80 degrees Celsius. Errr…what?

I suppose that is a good thing, but how?

7

The only thing I can think of is maybe the thermistor/heat sensor got knocked loose somehow. Which might be completely coincidental to the weather.

8

My only personal experience was when lightning hit our chimney with antenna attached. Totally fried 2 TVs. I guess that is a benefit to cable! :smiley:

9

Some additional (and probably completely useless) information:

National Electrical Code recognizes two different types or stages of protection from surges and induced voltage. “Primary protection” is intended to safely divert excess current (presumably at very high voltages) to the electrical ground. This can be accomplished several ways, but split-caps are one common way to achieve this. Naturally, you need to have a good grounding connection and the conductor has to be sized properly for this to work effectively. “Secondary protection” is intended to stop the excess current from passing through to the appliance or the device being protected. The most common way to do this is with an overcurrent device (fuse or circuit breaker). MOVs can also be used to increase resistance as voltage increases.

When evaluating a surge protector/system, you need to look at all facets of its operation, as well as the quality of your grounding connection.

10

For old school type appliances it would take a pretty significant power flicker or surge to damage them.

But modern appliances often have digital controls and those are easily damaged. And replacing such controls is often costlier than one would expect.

A laptop plugged into a power brick plugged into a power strip with a good, sort of new, surge suppressor is fairly well off. Not completely immune to a lightening surge but will be okay for less serious stuff.

A special note on AC units. When an AC shuts off there’s some back pressure from the coolant that needs to be reduced before it can start another cycle. Units will have automatic timers to prevent a quick off then on.

If the power goes off and comes back on that timer might not be going right and the compressor can overwork trying to overcome the back pressure. It’s possible this can damage the unit.

A few weeks ago we had a power glitch and the AC tried to start up again. I noticed the sound wasn’t right and immediately shut it off for 15 minutes or so. Once back on it worked fine. But the damage might accumulate.