Comment by tempaccount5050
10 hours ago
Are you in an area with a bad electrical grid or something? In 40+ years I've never had a single device get fried from a surge/storm. My "surge protector" power strips are from the 90s and probably don't even work.
Not only should you get rid of them, but also they are a fire hazard.
Also, do not accidentally plug surge protectors into each other, metal oxide varistors can star fires _without_ meaningful surge conditions when you do so.
I prefer to buy products without MOVs entirely due to the risk, with the exception of one, Tripp Lite Isobars; but I prefer to use series mode protectors such as Brickwall or SurgeX.
> Not only should you get rid of them, but also they are a fire hazard.
Are they not a fire hazard even when new? MOVs do tend to degrade with use (especially after they've gone conductive to snuff one or more surges). But AFAICT we can't really know, without potentially-destructive testing, whether a given MOV is in good shape -- whether installed last week, last year, or 30 years ago.
> Also, do not accidentally plug surge protectors into each other, metal oxide varistors can star fires _without_ meaningful surge conditions when you do so.
What is the mechanism that increases risk for MOV-sourced fires in this arrangement?
I've also noticed that many of the power supplies I've taken apart (for very pedestrian consumer goods) have internal MOVs on their line input. Whatever the mechanism is that increases risk, isn't using one external surge protector already doing that in these instances?
> I prefer to buy products without MOVs entirely due to the risk, with the exception of one, Tripp Lite Isobars; but I prefer to use series mode protectors such as Brickwall or SurgeX.
I prefer to avoid MOVs, too. Broadly-speaking, diodes seem like a better way to do it. (Transtector is another reputable brand that uses diodes.)
---
That all said, I've noticed over the years that problems with dead (presumed-to-be-hit-by-a-power-surge) electronics tend to follow particular structures. And the reason for this seems related to grounding more than it is anything else.
So when I find someone (a friend, a client, maybe someone online that I'm trying to help) complaining about repeated damage, I often ask about grounding. Almost always, it turns out that they've got multiple grounding points for the electronics: The electric service has one ground rod, and the telephone/cable feet/satellite/whatever is connected to some other ground.
This might be a dedicated rod, maybe a metal pipe; whatever it is, it is distinct from the main service ground. It happens all the time. (It is worth noting that the NEC prohibits this kind of configuration unless extraordinary effort is put forth. See 800.100(d), for example.)
The way that MOVs -- and avalanche diodes alike -- behave combines with the fact that the earth is an imperfect conductor, such that having multiple ground points promotes dynamic ground loops that can provide quite large potential -through- the electronics that we seek to protect.
The problem appears suddenly, and repetitiously. Everything is fine, and then ZANG: The cable modem gets smoked along with the router it is connected to. So the modem goes back to Spectrum or wherever to get swapped, and the router gets replaced again, until the next time: ZANG.
TV connected to satellite receiver, with coax incorrectly grounded? ZANG. Over and over again.
I'd see it all the time when I was a kid back in the BBS days: The phone line was grounded improperly, and computer was the only thing that connected to both electricity and the telephone line. Some folks would go through several modems over the course of a summer, which was very expensive -- while most people had no problems at all. Next-door neighbors would have completely different failure rates.
Structures with correct grounding tend to do very well at avoiding these issues, and I've fixed these conditions in subsequent years more times than I can count.
(A coworker installed a phone system at a business once, wherein he made extensive use of Ditek surge suppressors -- on the incoming POTS lines, and on the power inputs. It blew up one day. So he called Ditek to try to get at least the cost of the phone system hardware covered. They asked him to draw up a map of how the building was grounded and send that over, so that's exactly what he did. When they saw his map, they very quickly identified a ground loop and denied the claim.)
This. Same timeframe and I've lived through both lots of lightning storms and in areas with lots of power failures. Some of them intermittent and essentially caused by transformers blowing up. Like earlier this winter, we had multiple storms where you'd hear a transformer blow up, in many cases even seeing the sky light up as well from it, power going out, couple seconds, power coming back, next transformer blowing out, rinse, repeat.
On the other hand I've read about plenty of stories of the "cheap" UPSs you'd usually buy as a consumer (not to name any brands coz I've never had any) actually causing such issues in the first place. Without any actual surges from the grid.
That said, being totally not superstitious (for real, but someone's gonna "kill me" if they find out I wrote this and something dies from a surge...), now I guess I need to knock on wood like seventeen times ...
I do use surge protectors when we're on generator power temporarily.
The things people often call "transformers blowing up" are usually not transformers blowing up.
Instead, it's usually just overhead wires that are too close or literally touching, often from influences like wind and ice. The electricity arcs between the wires, creating bright blue-white flashes that can be seen from far away, sometimes with instantaneous heat that makes hunks of metal wire evaporate explosively. It can be violent and loud, and repetitious as different parts of even a single run fail.
Transformers can certainly blow up, but that's less common. They're (generally) filled with oil for cooling purposes, and they're massive things that tend to take time to get hot. A failed transformer can produce arcing and blue-white light, but if things are that hot then the oil is also ready to burn.
And when the oil burns it isn't blue-white -- it burns with about the same yellow-orange color we saw the last time we accidentally flambéed dinner on the kitchen stove, or a Hollywood fireball.
A bright flash without a fire is probably not a transformer.
Here's a video of a transformer actually-exploding (note the prominent fireball): https://www.youtube.com/watch?v=oFkfd31Wpng
And here's a video of what someone describes as a transformer exploding, even though there are no transformers in the video: https://www.youtube.com/watch?v=rHVh0KwG_0k
Haha, I hear you. But yes, it really is transformers blowing up sometimes. Sometimes it really is just branches blowing up the line, sure.
A branch hitting a wire, happenes all the time here too. Lots of trees in this community. The video of a transformer you shared: that's not the transformer I'm talking about. That's at a transformer station.
I'm talking transformer on a street pole. The kind that hangs right across the street from me. This kind: https://www.youtube.com/shorts/y3E7avUvj6I
See it's the kind in your second video. It's a transformer. You just chose a narrower definition I suppose. It's a https://en.wikipedia.org/wiki/Distribution_transformer ;)
And yes, I know it's transformers and not just wires (but also wires do happen definitely) coz I do walk the neighborhood regularly and I can tell when a transformer is new vs. old up there. Ours is old. The ones a few streets over sometimes are very new and I see the Hydro trucks go by the next day(s) to make them new ;)
Again, like seventeen times knock on wood but the ones next to us have not actually blown up. But three streets over, seen the new ones. Literally last weekend, we had an ice storm come through and while no blowouts we could see or hear, the outage map showed plenty of failure.
It's not just cheap UPSes, it's cheap surge protectors as well. They exist because the vendor can throw in a MOV costing a few cents and increase the price of the power strip by 50%, not because they're any good. MOVs are sacrificial components which have either degraded to uselessness by the time they're actually needed or, if they're still working, can explode or catch fire from the energy dissipated. Even if they don't, all they're doing is converting an x-kV spike on active into an around-x-kV spike on neutral or ground. If you want to do it properly, use a series tracking filter, not a "surge protector".
No offense, but can you tell me how my 4.5 kW generator is gonna generate that kind of power surge?
1 reply →
When I lived in Costa Rica, I lost three surge protectors in a year to power surges. During one such power surge, I didn't notice that the red light indicating surge protection was already out, and a power surge fried my (knockoff) Macbook power adapter, leaving me without a way to work for a day.
Not too bad, just rural. We used to lose stuff every 10 years or so.
One day The Big One came along and fried nearly everything. "Once burned, twice shy."
Hopefully someone can learn from my mistake and not have to do it post-mortem.
If your close neighbours have surge protectors then you benefit little from installing your own.
Another perspective: we should install whole house surge protectors if we can afford them, not only for ourselves, but to help our neighbors - even if in reality the help is minimal and they need their own as well. In the best case scenario, if everybody in a neighborhood has them, each individual house will be more resistant to surges than if they were the only house with one (five houses with surge protectors nearby is a lot better than one) - everybody wins.
You might as well phrase that as "If your close neighbours have gotten vaccines then you benefit little from getting your own."
We live in a society. Everybody chips in. And each surge protector adds to the robustness of the grid.
Eh. Most nice power strips are also surge protectors.