In one of my boxen, both my power supply and network card died while in overnight hibernation - why?

And: What must I do to appease the electricity Gods so that I don't lose more hardware?

In my home I've got... five computers in various states of use (monthly through to continuous), and I've lost power supplies for all of them, including the laptop, generally in lumps (several components around the same time). These losses have also included other bits and bobs, including a hard drive.

Do I need some kind of power conditioner? Those power-boards with surge protection, that's just a marketing lie, right? And a cheap UPS isn't going to filter the electricity any, is it? So what do I do, spend up big?

  • If you do get a UPS most allow you to install corresponding software to monitor their work (PowerChute for APC). It's interesting to see how often they kick in and if there's a regular pattern to it.
    – STW
    Commented Aug 27, 2009 at 12:48
  • Also note that a UPS draws about 15amps, continuously! Most household circuits are rated at 20amps so plugging in a UPS will use 75% of that circuit. Do not plug in two UPS' to the same circuit (like I did). If you don't pop the circuit breaker then you'll potentially cause a fire (my circuit breaker didn't pop, but fortunately the only effect was the wire into the breaker melted). Typically the computer equipment doesn't draw 15amps (case 4 amps, monitor <1 amp, printer 1 amp, router <1 amp, cable modem <1 amp).
    – Arluin
    Commented Jun 30, 2014 at 15:03

10 Answers 10


I'm in an area with variable power and daily brownouts, and lost a lot of gear like you. I added a 2u APC rackmount UPS, big thing, and put nearly everything on it. It was wildly successful. The UPS would go on and off all day long, even when I could see no other evidence of power fluctuation. No more hardware losses. So I went and bought more of these big UPSs and put all my stereo gear on one, and other electronic clusters on another. The damage to my gear stopped.

I didn't buy brand new APC UPSs, I waited till they had sales and I bought reconditioned units. That kept the cost down.

Bottom line - I think you need something to smooth your electricity. I don't think it is a marketing lie, but I think you need more than the consumer versions of UPSs available.


My experience:

  • Cheap "surge suppresser" powerbars: useless.
  • Expensive "surge suppressor" powerbars: not quite useless. They will protect from momentary low spikes, but can't do anything about dips, brownouts, or blackouts.
  • Cheap UPS (ie APC Back-UPS): reasonable assuming you are not putting too much load on them and the environment they run in is reasonably (electrically) clean. I use them for my workstations at home, and they get fresh batteries every two years whether they need them or not, which they always do. I would not put server or mission-critical gear on such a UPS.
  • Mid-range UPS (ie APC Smart-UPS): adequate entry-level server protection. The problem is that you either over-buy UPS (ie a Smart-UPS 3000 powering one web server) or you end up gradually acquiring way more computer than the Smart-UPS can reasonably drive (ie: the same Smart-UPS 3000 powering a NetApp 760 with eight fully populated DS-7 shelves). Management (snmp, plus some form of software to deal with the load) is mandatory. Battery lifespan management is mandatory.

After that, the sky's the limit but you will end up having to install special electrical circuits to power them. The software to deal with them is also astronomically priced.

I always complain to customers that they are under-protected because they almost always are. And when they balk at the cost, I ask them what the cost to the business will be if "whatever is currently inadequately protected" fails.

For home, I currently only have one workstation -- only need one, thanks to VMware -- and it has its own BackUPS-750. The rest of the "networking gear" (one Linksys wireless router and one cable modem) runs off of a old Belkin 500Va UPS that currently needs a battery refresh.

So, bottom line:

  • Yes, get a UPS. Even an entry level one is better than the nothing you currently have.
  • If you are not running a particular computer, physically disconnect it from the mains unless you require some form of wake-on-LAN.

Under normal circumstances a UPS should protect you from spikes in the power net.

Ideally a UPS has a power supply that is disconnected from the power it gives to you PC that way it irons out most of the stuff. I vaguely remember some cases where a UPS won't help either but I'm pretty sure someone else can give a technically more correct answer, hence this is just a community wiki.


Yes. Power fluctuations, sags, and the like are not kind to computer equipment. It's not just marketing hype, although it depends a lot on the quality of power you get from your power company. It also depends on what other kinds of equipment share the circuit with your computers, and on what kinds of electrical noise they create.

So far, I have not lost any component of a computer connected to a UPS due to power-related reasons. (I did lose much of one computer that was connected to a UPS, but the power supply fan stopped spinning and it overheaded very badly. This wasn't due to electricity!)

I've lost several power supplies over the years -- so far nothing more critical -- on computers not connected to a UPS, and not after any obvious cause such as a thunderstorm.


I don't know why your equipment died, but I can tell you that UPS's have saved my business continuity multiple times.

I don't know how many servers (or how big they are) but a general purpose APC 1500 tower is probably sufficient for your needs, unless you run a rack of equipment.

It also has voltage sensitivity settings. This was useful for me as it was hooked to a generator, and without lowering sensitivity, the generator was not able to output a normal enough signal for the UPSes to cope.

You want battery backup if you want your equipment to be up (or at least, to power down gracefully)


Yes, yes, yes. But I don't know what to recommend you buy, because power is complicated stuff, vendors of low-end equipment just lie, vendors of high-end equipment don't give adequate explanations.

You want to filter out voltage spikes caused by lightning strikes and by normal fluctuations on the power grid. Perhaps these are two different problems to solve. Whatever the solution, some areas of the world have frequent lightning strikes. It may not be enough to have insurance against this, you may need real protection if you want to stay in business. I don't know how to protect against a nearby lightning strike, but I know they are common in certain parts of the world and can not be ignored. In the Tampa Bay area, it is common for businesses to be destroyed by a nearby lightning strike.

You want to clean up the waveform provided by the power company. I don't know how important this is, but it's not something you can totally ignore.

You need to handle very short power spikes and power dropouts. Ones less catastrophic than blackouts and lightning strikes, but ones that may be very common. There's a continuum between cleaning up the waveform and protecting against surges and blackoutes. I suspect power supplies will last onger if they are given cleaner power, and that random crashes will be less frequent. I suspect that most UPSes don't protect against an ugly waveform. This is speculation and guessing. But if a scope can make me nauseous, it might damage your power supply.

You need to handle a brief (less than 10 minute) power loss. It happens. It's common. This is handled with what people normally call UPSes. I can't state whether UPSes provide the other features I speak of as well.

You need to handle a multi-day power outage. Diesel generators and fuel contracts that provide guarantees even in a widespread emergency.

You need to consider whether your business needs require automatic transfer from the UPS to the generator. It's surprisingly cheap. For many businesses, a single event can cover the cost.,

Remember that UPSes always create a risk of fire. It's a large amount of stored energy.


Its also worth noting that its a good idea to purchase higher end power supplies for your computers. While its tempting to buy low end "500 WATT SUPER MAX AWESOME SUPPLY" for $20 off newegg, buying something a bit more expensive will net you better capacitors and diodes and help prevent problems like this as well. They won't save you from having your computers turn off during a blackout like a UPS, but they will be more likely to take the hit than pass it on to a motherboard or harddrive.

I remember when I bought a new motherboard with PCI-express built in for the first time, and I didn't have one of those crazy 24 pin ATX supplies. I went out and bought a cheap one, only to hook up one of the 12v +/- connectors going to a powersupply while the machine was running, to see that it was actually 10.5 volts. Took it back. The computer shop refused to take it back because it "wasn't broken". If it was running at 10.5 volts under low load, what happens if my DVD-rom is spun up, harddrive is spinning, video card is sucking down 100 watts, and I get hit with a slight brown out? Or, if I take a surge and the cheap caps in it can't take a small hit?

IF your feeling especially cheap, you can get used UPS's with bad batteries for very cheap (I think I got one for 5$ once at a flea market). Go to walmart and get a motorcycle battery. Tada, now you have a UPS with a brand new battery for less than 1/4 of the price.

  • you really shouldn't use car/bike batteries, they won't last long in periods without charge (IE running) Commented Aug 27, 2009 at 13:11

We have been dealing with this with Optiplex 760 and now Dell says 960 also has this problem. They gave us a list of rather expensive UPS (>$300) that all produce pure sine-wave power. The UPS are fine we tried with all but the PC itself. Once power out for a second or fluctuation the Optiplex dies. It is not the UPS or watt amount rather the "modified sine wave" power that the UPS puts out while on battery.

see http://en.community.dell.com/forums/t/19262542.aspx


In one of my boxen, both my power supply and network card died while in overnight hibernation - why?

Spontaneous failure of both point to either static or lightning on both A/C power and the network lines, or outright failure of the Power Supply, which affected one of the always-on circuits of your computer. Have you noticed some of your Ethernet LED's blink even when the system is turned off?

And: What must I do to appease the electricity Gods so that I don't lose more hardware?

  • You need essential systems on UPS.

  • You need everything else on a good, power filtering, lightning arresting surge suppressors, such as the Tripp Lite Isobar or the Brick Wall.

  • You need to eliminate any 2-to-3 prong 110V adapters.

  • If your network switch or router has a metal grounding tab, use it. Connect it by wire to the center screw of a 3 prong outlet plate.

  • You need Power Supplies with OCP, Over Current Protection. They shut down instead of die when shorted. (Not all cheap power supplies marked as OCP actually have OCP. I have proof).

In my home I've got... five computers in various states of use (monthly through to continuous), and I've lost power supplies for all of them, including the laptop, generally in lumps (several components around the same time). These losses have also included other bits and bobs, including a hard drive.

I can relate. At work I have seen countless power incidents, due to our proximity to a rather large and careless manufacturer with big power requirements, and a fragile local grid. We have regular brownouts, interruptions, sags, harmonics, voltage fluctuations and power frequency variations. At one point outside we had a 660V line cross some of our 120V circuits, resulting in the rare but veritable Swell or Overvoltage (aka surge).

What you are suffering is probably a combination of poor component quality and bad power. Power conditioning can lower the failure rate of poor quality components.

Do I need some kind of power conditioner? Those power-boards with surge protection, that's just a marketing lie, right?

Some are a big marketing lie, some are not. There are a few nuts on the Net, worshippers of the Real Earth Ground, who insist nothing can work unless it is a whole-house to earth breaker. They are wrong. Of all the power issues I listed, a whole-house breaker can only protect against the overvoltage, but a good surge protector can protect against all but the sustained interruptions. A good UPS will protect against everything. When the 660V line cross our 120V circuits, everything powered-on not on a power strip died. Everything on even the cheapest power strip survived, except for the power strips. Quality power strips will protect against more subtle voltage shifts.

And a cheap UPS isn't going to filter the electricity any, is it? So what do I do, spend up big?

A good modern UPS has both boost and buck capability, meaning, instead of switching to battery during minor power issues, it will just fix the issue. You may have to pay a little more to get this capability, but (for example) all our recent 1500VA UPS systems have it. Once you get to a certain size of UPS (600-700VA) you are more likely to get it included be default.

When choosing a UPS, don't equate VA with Watts. A 350VA UPS cannot support 350W of power draw.


Power Conditioning with an ISOLATION TRANSFORMER is the only sure way to protect hardware from AC line noise, spikes, surges, transients, etc. If you have an APC UPS for battery back-up, you don't have adequate power conditioning. You should add a transformer-based power conditioner to the APC UPS for complete protection.

The best ones out there are ONEAC/POWERVAR, which we used to eliminate soft failures (error messages, lock-ups, etc) and hard failures (board and power supply failures). Yes, more expensive, but compared to cost of downtime to our business, they pay for themselves within months!

Here's a link to some of their products: http://www.gryphon-inc.net/#!powervar-power-conditioners/pj5r3

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