The electric company that serves our mobile-home park issued the tenants a notice that they would be shutting our power off temporarily today to do maintenance on the equipment.
I did not switch my computer on today–I’m using my Smartphone–lest the sudden loss of power cause damage to the computer. But the computer’s power cord is plugged into a surge protector instead of an ordinary power strip. Does this make a difference?
Yes. It generally isn’t the loss of power that is the problem, it’s when the power goes back on, it’s initially unstable and could burn some electronics up. Surge protectors are designed to break the circuit before a powerful jolt gets to the equipment.
Losing power isn’t going to hurt anything. What could hurt is if somehow they created an overvoltage situation when they bring the power back up (i.e. a power surge). Personally, I’d just use the computer and not sweat it if there’s not a clear time when the power is going down and coming back up; most computers can handle a few unplanned outages without issue.
Surge protectors work for weird situations where there are power grid malfunctions or lightning strikes that raise the voltage very high very fast.
Circuit breakers on the other hand, are more for use against overcurrent situations, where something’s drawing too much current for your wires to handle. They’re measured in amps, not volts, as a result.
Chances are there wouldn’t be a problem, but just to be safe, I personally would turn the surge protector / power strip / whatever off. That way if they accidentally do anything weird on the power line side you won’t be affected. Same for the television. If your computer or TV or other electronic device isn’t on a power strip that can be easily switched off, unplug it. Alternately, you can just switch of the main breaker in your mobile home to make sure you disconnect everything.
Surge protectors only protect against basically surges and spikes. They don’t protect against brownouts or rapidly cycling power or weird things like that. If you want protection from that sort of thing you’ll need a UPS.
Most likely, the power will switch off and later will switch back on and both times it will be a fairly clean switch. You never know when Mr. Murphy is going to strike though, and someone ends up doing something like dropping a live 3600 volt line across the “turned off” 220 volt feed to your trailer park. The chances of something bad happening though are very, very, very small.
A lot of surge protectors, especially older ones, are made to protect against one surge and then be replaced, but don’t have any easy indication that this has happened. I don’t trust the surge protection in typical power strips to protect equipment, I’ve made the mistake of using an older surge protector and having to get quite a bit of electronic repair done. If you’re mildly concerned, unplug any computer, TV, or similar devices until the power work is done, though they’ll probably be OK. If you’re more concerned, a basic UPS will filter the power coming into your equipment against just about everything and give you some time to shut down in a power outage for $40-$60.
Exactly what is a UPS as you use the term here?
Uninterruptible Power Supply. It’s a power switch and surge protector with a batter backpack, so the power never goes out. There are also larger versions with generator instead of battery backup, for cases when the regular power supply might be unavailable for more extended periods.
Oh.
Don’t waste your money on a cheap ups.
I worked in a high rise building. In one floor I lost the neutral in one area… So I had a floating neutral causing the voltage to vary depending on the load. I checked one out let and my meter read 190 VAC. In the offices with a cheap UPS management had to buy the tenants new computers. In the offices with the better UPS we just had to buy new UPS and there was no computer damage.
In case you need to bake a cake while you’re camping?
Oh, “battery backup”.
–Mark
If you have a laptop with a working battery, you have a built in back-up.
Unplug other stuff.
If you have $$$ invested in TV or other, buy a cheap Wall*Mart one time cheapo surge protector that is not a power strip for about $6-8 … ( one hit & it is dead.) You know for sure.
Plug into that a decent surge protector like a “Trip-lite” and then plug the battery back up into that and your high $$$ equipment into that.
Two kinds of battery backups.
- Senses voltage drop and kicks in the back-up power using the battery.
- Much better & much more $$$ is the kind that run off the battery all the time and just keep it charged up. No worries about reaction times for voltage spike or brown outs or off. It is doing the power 100% of the time.
They are more expensive.
When you can see lightening in the area, just unplug it all and wait. What do you have to do that is so important that you risk several thousands of $$ in equipment and material you have not backed up yet?
You do clone all your drives and keep them in a fire proof safe that fires, floods and the crazy ex can’t get into. At least once a week or more times for important stuff.
I just clone C drive and pictures that can’t be replaced and some legacy programs that I don’t want to lose. Important things like will, medical power of attorney, my little black book, you know, the important stuff.
Bawahahaha 
i, for one, do not wish to make light of the situation. as engineer_comp_geek suggested … it really would serve you well by disconnecting the power-main. the neighborhood i live in has brown-outs often … the power is underground … transformers go out on regular basis. and, because of this, i almost lost my fridge 'n microwave 'n stove/oven (repaired each one manually). [yes, i consistently utilize surge-protectors on most electronics.]
perhaps murphy and his god-forsaken laws really has vendetta against me … sometime it really does seem that way.
The power, as it turned out, did not go out at all. Apparently someone from the electric company spoke to the park manager and said they *may or nay not *turn the power off. (I spoke to the park manager about 11:15 this morning.) I was in and out today; if the power had gone out there are at least two electric devices on which the time display would have been flashing when I returned. None was. If they turn the power off tomorrow the tenants will probably never trust them again.
Last December there was a power failure here for 13 hours–about 2:30 p.m. Tuesday to 3:30 a.m. Wednesday, one week. Because of a quirk in the blower mechanism in our furnace the wiring insulation started smoldering; to make a long story short, we had to have the mechanism repaired.
So you have plugged into something that does not claim to protect from typically destructive surges. And may compromise robust protection already inside a computer.
Did you read its spec numbers? Or just assume surge protector and surge protection sound alike. So must be same?
Destructive surges can be hundreds of thousands of joules. How many joules does that protector claim to ‘absorb’? What happens when a thousand joules protector tries to ‘absorb’ hundreds of thousands of joules? This list of bad things includes fire.
A UPS typically has tinier spec numbers - hundreds. So why do so many recommend a tiniest joule UPS? It is more expensive. Therefore it must be better. Most who recommend have no idea what it does. And ignore numbers.
Blackouts do not cause hardware damage during the power off or power restoration. But some blackouts are caused by (preceded by) a surge. That surge may do electronic damage. Then wild speculation only blames what they observed - a blackout. Power cycling never damages properly designed appliances. Other anomalies that may precede a blackout may cause damage.
Spend many times less money for effective protection - from an anomaly that might happen once every seven years - a surge. That means properly earthing one ‘whole house’ protector. To even protect those near zero joule protectors. And a heater.
Protection is always defined by what harmlessly absorbs hundreds of thousands of joules. A ‘whole house’ protector connects that energy low impedance (ie less than 10 feet) to single point earth ground. A protector is only as effective as its earth ground. ‘Whole house’ solution has that. Plug-in (magic box) protectors do not.
Westom, I should point out that in the OP I mentioned that this was a deliberate outage effected by the electric company as a precaution to take before equipment maintenance. And as I noted in my last post, they elected not to do so at all yesterday anyway.
But you should be familiar with what makes linemen mistakes, lightning, stray cars, and tree rodents irrelevant. Others worried about power restoration causing damage. That does not happen. But other anomalies do. What others recommended (ie UPS) does nothing to protect hardware from AC line anomalies.
Had a linemen restored power and made a mistake, then something that coincided with power restoration might have caused appliance damage. If your computer needed protection, then everything needed that protection. That was the point. Other recommendations (ie UPS) would have done nothing useful for future hardware destructive anomalies.
Concern was not just for a possible linemen error yesterday. That existing protector may even compromise protection inside the computer. What also protects a blower motor? Recommended was for all anomalies even years from now. It is all a same solution.
A good UPS can protect.
A cheep UPS has the input connected to the out put. The battery floats on line with the utilities power. Any kind of spike or voltage drift is passed straight through and has not protection.
The better UPS rectifies the input 120 vac to 12 vdc and is connected to the 12 vdc buss. Also connected to the 12 vdc buss is the battery. The 12 vdc buss also connects to an inverter that converts it back to 120 vac. A short term spike is adsorbed with little damage. But a constant high voltage will take out the rectifier and protect what is being powered by the UPS. I know because I experienced this in a building that had 190 vac at the outlets when we lost the neutral in several offices. The good UPS protected the computers and we had to buy new UPSs, the offices with cheap UPSs got new computers.
There are different sorts of UPS designs, and also different forms of line regulators and protectors. You get what you pay for, and the extra money often goes into more comprehensive designs.
The most useful UPS design is a dual conversion design. There is a power supply run from the mains that is used to both charge the battery and to run an inverter. The inverter takes DC power from the battery/power supply and turns it back into mains AC. These designs provide very good protection from just about anything that the mains supply can throw at them short of a lightning strike. The design provides for close to complete isolation from the mains (via two transformers) and the input can be designed with quite comprehensive protection. ETA - Ninja’ed on the double conversion UPS
Cheaper UPS systems avoid the cost of double conversion and don’t provide the same level of protection. They will keep things running in the face of power loss, but not much more.
You can also get line conditioners, these can be big auto-transformers or ferro-resonant systems. They regulate the power, and since they have a lot of iron in them can act to protect against serious spikes, but won’t protect against really bad stuff, or accidents/screw-ups that drop a high tension line on your mains. If the core saturates things can go bad. These are very unusual for domestic use anyway. (Some HiFi nutters use them. They weigh a ton.)
As noted above, surge protectors can mean anything. They are a device that is intended to clamp the voltage on the line to try to stop spikes causing trouble. But in doing so they need to adsorb the power of that spike. Some are single shot. Some recover after they cool down. You get what you pay for. Most of the stuff you see in power strips and the like isn’t worth giving the time of day to. Any reasonable quality piece of equipment will usually have protection built in that exceeds what you get in those strips. No surge protector can protect against an accident that drops a high tension line onto your mains. Those are not surges. A surge goes away.
When power was restored after the 13-hour outage last December, the furnace’s automatic mechanism attempted to start the blower. But the wiring, which was very old, apparently had a short and that caused the insulation to smolder (according to what the fire department captain told us). The repairs we had made, corrected the problem, and when the repair guy reconnected everything the automatic mechanism started the blower up again. (We had also had a power failure after the 1994 Northridge earthquake; four hours after the temblor and outage, the electric power was restored and the heater started up again without incident.)
Looks like we’re getting into the topic of surge protectors while we are here.
Not all surge protectors are made equal. The cheapest ones just have MOVs between the lines. An MOV is a metal oxide varistor, and basically when the voltage gets too high it turns on and shorts out the line, clamping the spike. This usually fries the MOV in the process. There’s no visual indication that the MOV has been fried, though. Better surge protectors will have an indicator light that tells you if the protection circuitry is still functional.
When comparing surge protectors, there’s a few things you want to look at. The first is the joule rating. The higher the number, the better. A cheapie surge protector might only have a rating of a couple hundred joules. A better one might be a thousand or more. Keep in mind that a lightning bolt is a few billion joules. You can’t buy a surge protector that will stop a direct lightning strike (for that you need to install big things like ufer grounds, halo ground rings, and Faraday cages, which gets you well beyond the budget of most household things).
Another rating is the clamping voltage. The lower the number the better. A surge protector that clamps at 400 volts will let a 350 volt spike through, where one that clamps at 300 volts won’t.
There will be two amp ratings. One will be how much current you can use normally, which will be something like 10 or 15 amps. A typical wall outlet is rated at 15 amps so an undersized surge protector or power strip shouldn’t be used with higher current devices. The other rating will be the fault current, and will be something like 20,000 or 50,000 amps. The higher this number, the better.
Like I said earlier, a surge protector won’t protect you from things like a brownout or a flakey breaker that is constantly making and breaking (turning your power on and off). For those types of issues, you can use a UPS. A UPS basically runs off of a battery and uses an inverter to generate the AC, so it is much more isolated from the main AC line. The incoming AC is only used to keep the battery charged. When the power goes out, the battery keeps everything running, at least until the battery dies. Our UPS systems at work will typically run for an hour or two. If the power isn’t back on by then, they shut down and the computers they control shut down with them (we tend to do a more orderly shut down before that happens).
A UPS protects you from brownouts (low voltages) as well. If the voltage dips, the battery keeps supplying enough current to keep the UPS output where it needs to be.
Note that a UPS technically isn’t a surge protector, and some of them don’t have any surge protection built into them at all. Most do, however. And again, when looking at surge protection, look at the same specs as for a power strip type of surge protector - high joule rating, high fault current, low clamping voltage.
There are also some UPS systems that don’t run off of the battery. They are more of a “hot standby” type of configuration. They run off of the regular AC line, and if that drops out then they switch on and take over. These don’t work as well. The switch isn’t instantaneous, and they tend not to have as much (if any) protection on the incoming AC line. And since they pass the incoming AC directly on to your devices, any AC noise or irregularities are passed through as well. Try to avoid these.
If your computer is a laptop, then you don’t really need a UPS to protect it since it is battery powered anyway. For a desktop though, I’ve lost more hard drives to brownouts than to anything else over the years. Depending on how clean and reliable your incoming AC power is, a UPS might be a good investment.
A UPS also has its limits. They are rated by how much current they can put out and for how long. Your typical UPS can run a desktop computer for a while, but it’s not going to run a heavy duty air conditioning unit. Brownouts and rapidly cycling power play havoc on compressor motors. If you are having these types of issues, it’s best to turn off power to your air conditioning and heat pump type units (and your fridge).
There are also the whole-house surge protectors that westom mentioned. These generally work better than the power strip type, but they also cost more and usually require an electrician to install them. There are some cheapies out there that if you look at the specs they aren’t much better than a cheapie power strip type of surge protector, but the good ones will have a much higher joule rating and fault current rating.
If you want to go all out, there are backup generating systems that you can install in your house. DO NOT just take a handy-dandy portable AC generator and make up a double-ended AC cord and plug it into your house. If you use that and don’t shut off the main breaker, it will back feed into the AC line and can harm or kill electrical workers trying to restore the fault on the line. The proper way to do this is with an AC transfer switch. If your power goes out or you are having major brownout issues, start your generator, throw the transfer switch (which disconnects your house from the incoming AC and moves it over to your local generator), and then switch it back and shut off the generator once the incoming AC is restored. These systems can be small and relatively cheap, or huge and extremely expensive. The smaller ones typically can’t power your entire house, so what many folks do is have two electrical panels. One panel has only the critical stuff that you want the generator to power, and when you flip the transfer switch it becomes energized by the generator. The other panel is for everything else in the house, and it isn’t switched over to the generator.