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PC Not Booting Until a Different Phase is Used?
2by4 asks: "I run at IT Dept for a small firm, our network room houses production &
development servers. Some machines are plugged straight into a strip with
no UPS. Here is the Mystery Problem: When the power glitches, the strip
machines go down, and some of these machine WILL NOT come up again until I switch
them to a new outlet. Once this happens, I can put them back on the original outlet
and they will work. Unplugging & replugging on same outlet is not enough. I have seen this on at least 5 machines so far, with independent confirmation. We can narrow the 'fix' to plugging into an outlet of a different phase (there are 3 separate 120v phases powering the room). The symptoms vary from no powerup, to frozen at the BIOS (depends on motherboard make), etc, but consistently, switching to a new phase fixes them. I tried the 'unplug-wait-&-replug' cycle, to no avail. Using a new outlet w/ a different phase is the only solution. Any theories? I assume the new phase is causing something to 'reset', but what? I can provide more details, but I am wondering if anyone has seen this before? I am completely and absolutely stumped. Our power is healthy, lightly loaded, evenly distributed and the power strips are new. I know I should have at least a simple UPS, but this mystery is causing me to lose sleep."
Obviously, I mean that you should do this with the plug UNPLUGGED.
Try resetting the circuit breaker on your "strips".
--
Twoflower
We had a customers Gateway machine that often did that exact same thing. Machine would refuse to boot or crash at the BIOS with invalid memory errors. Swapping the outlet to a plug across the room would cause the machine to boot just fine and stay running for months on end. Even moving the plug back to the original outlet would be fine for a while. The kicker is, it wasn't just the computer. Plugging in his palm would cause the palm to reset while sync'ing and glitch during regular use.
Our Fluke meter showed nothing special on the line and an APC UPS showed no spikes nor higher than normal voltage levels.
To this day we call it the haunted outlet and tend to just keep things away from it.
Why do overlook and oversee mean opposite things?
"Mystery Problem: When the power glitches"....
then you say:
"Our power is healthy, lightly loaded"...
Not contributing to the solution of your problem, but my office doesn't get "regular" giltches like yours seems to, even though our power is "healthy" too.
Sounds like you need to call your power company.
Modesty is one of life's greatest attributes
Gnomes?
(Flunking, in case you couldn't tell)
Test the ground line on the power strip.
You mention when your power 'glitches'...brownout or blackout or spike?
We are a light industrial building in a heavy industrial park, and I swear the power goes glitchy 2-3 times per year.
We'll get brownout and blackouts, and when the power comes back it SEEMS like it's on, but only 2 of the 3 phases of the A/C actually comes up, meaning (depending on how it's wired at the *circuit box*) some circuits are dead, some are full, and some are semi-brownout (our flourescent ballasts LOVE that half-state.....not).
That third phase sometimes doesn't come back up for hours.
I have no idea if this is of any help, that electrical stuff is arcana to me, I'm just reporting what we've discovered.
-Styopa
I think starting the article with "We have since gone out and bought some fairly inexpensive UPS's to eliminate this problem but nonetheless the phase detection has piqued my curiosity
....... Thus ends my attempt at wit or whatever
Unplug the machine, hold the power button for about 10 seconds, plug it back in. You really don't want your machine bouncing on/off during power problems. Either that or go get a cheap UPS.
Did you modify the phase variance?
Have you measured the voltage on the outlets when the computer is not working? . Anything below 100 will not work. If one of the phases is overloaded and thus your circuit not balanced, you'll have a serious voltage drop on the outlets of the overloaded phase.
We just got a 30 amp circuit installed for a 3kv ups. The UPS once powered up had a "check building wiring" light on the back that came on and stayed on. The cheapy circuit tester indicated that the wiring was fine along with an electrician verifying that all the wiring from the panel to the outlet was correct. One more symptom of this area is that light bulbs blow out much more than normal, although the PCs have not had anything unusual happening.
We had the original electrician who installed the line back out to test. His voltmeter was showing about 20-30V between the neutral and ground. According to code (IANALE), these lines are supposed to be connected at the panel. Apparently without this connection, the two sides coming off the transformer can float in the voltage which may have been responsible for the light bulbs blowing. Once the neutral and ground were connected, the wiring fault light went out on the ups and everthing has since been fine.
SHORT RESPONSE: Have a licensed electrician check out your circuits.
As someone already said, when you have weird electrical problems, suspect the ground. Remember that ALL devices and connections on a computer system need to be connected to the same ground. The exception to this is Ethernet network connections, which are very well isolated.
Printers must be connected to the same ground, for example. Check the integrity of the ground; their should be low resistance, as measured with an ohmmeter after you have turned off the power, of course.
Also suspect that there is some weird voltage riding on the power. Is your power clean? The only way to check this is to look at it with an oscilloscope. Oscilloscopes make an instantaneous on-screen graph of the voltage.
All computers should be connected to battery backup power supplies, too of course.
Boy, talk about the long arm of coincidence. This just happened to me *last night* with my Replay TV. It wasn't showing any life whatsoever, but I checked other devices in the same outlet and they were getting power. So I figured the Replay TV was cooked. I pulled it out, and thinking I might try and fix it (i.e., kick the damn thing a few times) I plugged it into a different outlet and it worked just fine. I took it back to the original outlet, and it works just fine. This hardly answers your question, but another data point never hurts.
"My girlfriend's got sodium laureth sulfate hair."
BOFH excuse #3456 (Phase of the moon) can now be supplemented by BOFH excuse #3456b (Phase of the power supply).
If power's coming and going that often you need something. As well as handling short power-outs without any problems, even the consumer-level ones can provide some monitoring of the input voltage. If you're having trouble getting the cash signed off, "I can't start this machine without it" should help.
However, it does sound though like you need to get someone competent to check over the electricity supply. I'm not, and neither are you. I'm assuming that you're in the US (from the 120v comment) and I'm surprised that having outlets on three phases in one room in an office environment isn't against the building regulations over there. I suspect that all it needs is someone to plug a machine with dual PSUs into two different phases and a bit of dodgy wiring for some very interesting results.
If your boss won't stand the cost of that you might want to check out your health insurance plan.
This happened to me once with my old Suse box. The really strange thing was that it's plugged into the same outlet as my other computer, and it didn't seem to have any problem at all. After it started working again, I just wrote it off as one of those things beyond my comprehension. Useless, I know, but at least you know it's happening to people on the residential end.
Ultimately, both of them quit working altogether. IANA[electrician] and she didn't feel like hiring one, so I just got her another adapter and she unplugs it before using the shredder. I'd love to hear someone explain well why this would happen, though.
I've run into this type of issue several times. The issue is'nt so much moving the plug, it's that the MB maintains power for up to a couple of minutes after the power is lost. If the Power glitched, the MB may be in a non-useable state. The way I solve the problem is this:
1) Unplug the Power supply.
2) Hold down the power button (on the front) for 10 seconds.
3) plug in the power supply
4) Turn on the computer.
I solve this issue with most of my systems by connectiong them to a UPS. Some crash on their own so often that they're not worth a UPS.
This sounds like it could be a ground problem. I'd check (if you have the capability) the hot-to-ground and the hot-to-neutral with an oscilliscope on the effected outlet. Barring that you can check it with a multimeter, you may find that the neutral or the ground is inductively coupled to a hot phase.
Some other things to check:
The continuity between the outlet and the electrical box (all three wires).
That your grounding rod is correct for the type of soil in you area.
A different power supply.
Also, like a previous poster noted, try shorting the input to the power supply (when it is unplugged), that may give you a temporary fix.
- you may well have a grounding problem either on the strip or the outlet that the strip is plugged into.
- when a computer is in the "won't work on this strip" state: unplug it and ground each of the 3 terminals momentarily. You can do this by simply touching all three prongs to the metal face plate of a switch or plug. (this is similar to the suggestion that someone gave about shorting out the prongs with a screwdriver but better). Then try the computer. If this works then you may have a floating ground on the strip or somehow voltage is getting induced onto the ground.
- you can buy a simple tester to test the wiring on a duplex plug. Home Depot usually caries them for less then 10 bucks. The plug into a 3 prong outlet and have 3 lights on them (2 orange and a red if I recall correctly). Depending on which lights light up tells you about the wiring and suggests what the problem is. I have even found high resistant neutrals and other such strange wiring problems with it.
Of course once you have tried this (or not) and have a better idea where/what the problem is, it is time to call a qualified electrician.Merlin.
Had this problem in my parent's house TWICE. The first time was that over 20 years of use, one leg of the mains had worked it's way loose from the screw holding it to the main switchbox. The second time was a halfway blown transformer on the pole. Didn't even think of this as a possible problem for TFA until you said something.
SJW: a person who perceives an injustice, and while correcting it, commits a greater injustice.
There should be some kind of inline tool that measures the 'quality' of the power coming from the line and flowing into devices. It could have like 5 levels or so and you could check the outlet for problems during real-time use. It could have a bunch of different functions, you know, like checking for electrical problems at the same time.
Unclean power is the problem that causes more crashes than people would like to admit. I've had my parents on the other side of the house start a vaccum cleaner and I've bluescreened at the same time..quite a few times..before. Obviously not a coincidence.
Job? I don't have time to get a job! Who will sit around and bitch about being broke and unemployed then?
It will not come up after being powered down. Haul the damn thing into the lab, turn it on, works fine. Haul the damn thing back to the printer station, comes back on ok. Power is fine at the printer station. Laserjet 5000 at printer station does not have the same problem. Other Laserjet 4000's don't have the same problem.
"Eve of Destruction", it's not just for old hippies anymore...
"Obviously, I mean that you should do this with the plug UNPLUGGED."
Man! You're just trying to take all the fun out of electricity, aren't you?
Seems that every computer connected to this old Thinnet network would eventually fail, either the motherboard or the network card. I found out the hard way if you grounded yourself to the case you got a good 70vAC shock!!
:-)
After a bunch of head scratching I tracked it down to one PC plugged into a floor outlet. Seems the outlet was cracked and had a carbon trace from the Hot to the Gound on its face. Got 4 year support contract with an AZ tribe for finding that one
Si vis pacem, para bellum! For evil to succeed good men need only do nothing!
sounds like you have one hot ac switched in your sytem, way back at the box perhaps, or at some junction (bad splice some electrician hid during install?). Besides that, can't tell ya. It's also possible you have a section of wire underneath the insulation that is so bad you get intermittent failures on that circuit. I've seen it happen just from a kink in the wire that was straightened out and used during installation. Cold, it worked,showed clean with an ohm reading, no breaks. Once some line resistance built up from plugging something in, it got a teeny bit hot and the break worsened, leaving intermittent or no workee.
I had this kind of trouble before: moving the computer to work to show a (very critical btw) presentation to a class and the computer hanged after BIOS... bringin it back home to find out it was working perfectly. It had no excuses other than some power issue, but other computers just worked fine on same outlet.
I'd look into the docs on the UPS you have to see if there is a way to hook up a ground lug on the *output* side of the UPS to tie it to building ground. I'd also get one of those testers over at Home Depot to see if your outlets are all actually grounded.
I bet if you leave it plugged into the wall, and unplug the *other* connections (network, video, etc.) for a few seconds, it will come up.
- "History shows again and again how nature points out the folly of men" -- Blue Oyster Cult, 'Godzilla'
1) As other have pointed out, bad grounding on one or more phases.
2) Bad neutral on one or more phases.
3) Voltage drop on one or more phases.
For the first three get an electrician out, don't mess around with three-phase power.
4) Electrical noise on one or more phases, this may not be caused within your computer room.
5) Equipment connected on different phases affecting each other, for example a printer on phase A and a server on phase B.
6) Borderline power supply in a machine affected by one or more of the above conditions.
7) Faulty power strip(s).
8) Incorrectly wired plug(s) or socket(s).
Ed Almos
The more corrupt the state, the more numerous the laws. - Tacitus, 56-120 A.D.
Your parents must have very very unusual power. Three phase power is hardly ever found in houses. In the US, we don't even have two phase power - we use a single split phase.
Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
Buy or rent a power quality monitor, such as those from Dranetz. You probably will find your power isn't as clean as you thought, or your building is wired wrong.
I would venture that the problem may be a bad ground on one circuit. I have seen problems where a computer plugged into a peripheral, say a printer, would crash if the peripheral was on a different power circuit, due to a problem with ground and neutral not being connected (or something like that).
It's been a long time since high school electronics, but I could see a grounding-related problem more simply than a phase-related problem.
Tom Swiss | the infamous tms | my blog
You cannot wash away blood with blood
This comment needs more attention. Look at the larger picture here. You have identified a solution without identifing an issue. You say the solution is to change "phases." But what is the problem?
My first reaction to the parent question is what do you mean by "different phase." Do you mean your server room is fed off of 2 or 3 phase power? And that some outlets are fed off of different branches? Or do you mean you change to a different circuit?
What is likely is that certain voltage rails aren't settling out and isn't allow your power supply to raise the power-good signal. Or in the case of partially booting systems, isn't bringing all of its rails up correctly. Why does moving to a different outlet change this? How long does it take to move?
It is more likely the process of moving, the time involved or how you connect/disconnect things are allowing capacitors in the PS to discharge.
Anyway. I do not think you have correctly identified the behavior, but somehow you already know the solution.
The post provides a good solution. Unplug and "turn-on" the machine, then plug it back in.
It was two phase- did I say anything different? But the result is the same- the circuits on the phase that was blown on the transformer or the phase wire that had worked it's way loose went out, or rather browned out, while the other phase stayed good.
SJW: a person who perceives an injustice, and while correcting it, commits a greater injustice.
in the US almost every house if not every house has 2 phase current for the 220 outlets powering heavy appliances such as washers, driers and dishwashers. Commercial and industrial facilities get 3 phase and get higher voltage connections used for heavy equipment.
Snowden and Manning are heroes.
I concur with the others who have talked about ground problems, but here's an extra question:
Is the computer plugged into anything else when it's being glitchy? Printer? LAN? Modem? It may be that there's a difference in ground potential between the computer and the peripheral that's causing a current flow between the two.
If not, ignore the above but check the grounding anyway.
Sean Ellis
Follow OfQuack's antics on Twitter.
That is not two phase power in the same sense that there is three phase power. That is what is called Split Phase power, but it is still technically one phase.
(Or some other kind of scarlet swimmy thing...)
Turning off and on at the same mains outlet will generally be "off, count 10 elephants/mississippis, on". Moving outlets usually involves physically moving the damn thing around, or unplugging a wire from one socket, taking the wire across the room and plugging it in somewhere else. Consider the time it takes to do this - could the power-off time be the significant factor, and the phase thing is a coincidence?
Or on a similar theme, how about disconnecting the mains cable (and waiting some time) so that the mobos are fully powered down? That happens naturally when you disconnect the cable and plug it in somewhere else. Maybe try repeating the same action, but on the original phase.
Not to doubt the fault-finding you've already done, but just adding a bit of devil's advocacy to suggest possible alternative situations with the same symptom.
Grab.
Um, Wrong.
We definitely have the power, it may not be universally connected residentially.... If you have 220 in the house (typically for an electric stove or a clothes dryer), you have two phase coming in from the street.
You may also have multiple phases coming in if you have a higher load. This office is that way.
The multiple phases may not be wired, but they are definitely available. I looked into setting up a 3-phase circuit to power an old SparcServer 2000E in my garage at one point. I had everything I needed for 2-phase, not for 3, and it was going to cost a bomb to bring in from the street. A colleague has a Cray running in his dining room (and an $800/month power bill), and it is definitely on 3-phase.
BTW, I think the previous posters observation about loose neutrals sounds like the most likely cause in the house. Call in a competent electrician. He can tell you whether you or the power company has the problem.
--RED
If you have 220 in the house (typically for an electric stove or a clothes dryer), you have two phase coming in from the street.
Not really. House 240V power is created by connecting one phase of a three phase feed to a transformer with a center tapped output. The center tap is grounded and voila, you get split phase 240V power. It consists of a ground, plus one leg at +120V and the other at -120V, referenced to ground of course. Take the potential across the two of them and you get 240V. While these legs are separated in phase by Pi radians, this is not what is referred to as two phase power.
"Nature doesn't care how smart you are. You can still be wrong." - Richard Feynman
Have an electrician come in and do some wiring checks and fixes. You have a combination of two problems causing you to see this.
1: You have poor to non-existent grounds on one or more of the phases. This can be tested for by the electrician.
2: The HOT and Neutrals are swapped around and generally this isn't an issue except that *modern* power supplies are getting cheaper and cheaper and this usually means cutting out *some* parts like full-wave bridges for half-wave diode sets, and similar tricks. This then makes the circuit more effected by incoming AC and it's phase against ground or what little there is of it. (hence the reason for #1) There more than likely is a potential difference between the neutral and ground that is excessive and this is causing a cap-start circuit to ignite the switching and hence, a dead PS.
Cheers;
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I have a friend that has 3-phase to his house as well. He had to pay an arm and a leg for it because his neighborhood just had a single phase delivery since it was residential, and residential is based on a single phase power. Yes, most residence are single phase power. While it is true there are two seemingly different phases that give a potential of 240 volts between them, that is still one phase. It's called Split Phase. The fact that the differential voltage is exactly twice normal voltage is how you can tell. Using 2 phases of a 3 phase system gives you 207 volts. A true 2 phase system (As opposed to just using 2 phases of a 3 phase system) have the phases 90 degrees out of sync, which is completely different.
Unplug the server(s) from the wall, press and hold the power button on the server for 5-10 seconds, and then try again. The PS often stores a residual charge that needs to be discharged before power up (also before removing components from the mother board).
If you've got 220, then you most certainly have your power coming from a center tapped transformer coil. That's a single phase, and you get 110 volts if you hook up one side or the other to the neutral. 220 comes from the two hot wires.
Check Wikipedia.
Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
The original posted said that 2 of the 3 phases would be on, and the 3rd phase would be down. You said you had the same problem, so actually yes, you did say something different.
Also, if you are in the US, you've got single split phase. If you're in Europe then you have two phase. Are you sure your parents have two phase? How much do they pay for that?
Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
I've experienced similar problems in the past, due to current leakage. Especially with different phases, but also commonly with poorly grounded devices or devices which had peripherals or cables running close to sources of high levels of common mode noise.
Most commonly, when plugged into a peripheral or another device which is separately powered or grounded.
What was happening was small amounts of current leaking in through peripheral components was affecting the power supply... Usually to stop them starting up. ie, hit the power button, no start, no lights. The leakage was in the micro-amps region, but was enough to leak back through the motherboards into the power supply, and cause a false fault condition reading on start up, and the PSU would shut down before it got started.
The solution? In one instance, I decoupled the power rails. In another, better grounding. Another? Changed phase. The best solution was usually to find a better power supply that wasn't affected, but was not always possible.
Often in these circumstances you can feel the current leakage, as it's often at high voltage but very low amps. Sometimes it feels like a slight tickle when you touch rivets on the case.
Additionally, I've also encountered similar problems due to engineering faults, where a high impedance section of the circuit was acting like a radio antenna and was getting enough "reception" of a local signal (any strong electromagnetic radiation source) and causing a fault condition on power up that was not present during normal operations (when the applied signal was significantly stronger than the picked up signal).
Solutions there include EMF shielding and redesigning the circuits.
Problems like this are difficult to diagnose, as they are not always obvious, and there is very little you can do to test or troubleshoot directly. Often it involves experience and a little lucky guesswork.
GrpA
Enjoy science fiction? "Turing Evolved" - AI, Mecha, Androids and rail-gun battles. What more could you want?
If you opt to test the outlet with an O-Scope, first find out if the ground pin on the cord is tied to the ground on the o-scope inputs and chassis! Most analog, corded models are and you run the risk of putting 120-volts on the chassis or shorting the outlet through the o-scope. More than a few amateur electronics techs have missed this feature and blew up an o-scope or shocked the hell out of themselves. Electronic techs often use isolation transformers to protect the equipment and themselves for this reason.
Anyway, Gremlins only fiddle with airplanes.
solar flares.
What I would do is go to my toolbox and get my $2 outlet tester and bring it to work the next day. If that turned up nothing, I'd go with an exorcist.
Ethernet specifies 1500V dielectric isolation on all equipment. You can see the isolation transformer package on most ethernet cards, although some RJ-45 jacks have this built into them.
This is a surge rating, not continuous, but you can tolerate some pretty extreme ground abuse.
I'm reminded of the (apocryphal, but instructive) story of the car that starts or fails to start depending on the flavor of ice cream the driver chooses.
You seem to have focused on the phase of the circuit the same way the driver in the story focused on the flavor of the ice cream. Try to think of your problem more in terms of the facts, and less in terms of your hasty conclusions.
-Peter
Gnomes?
KDE would have the same problem.
I have had the same problem with my notebook. When I plug it in to certain plugs, it refuses to draw power from the AC, and beeps very loud very fast until I unplug it. If I plug it in to a different plug, it is fine, and then when I put it back in the "problem" plug it is fine again.
Your geek license is revoked.
NEW != work correctly. Just because you bought something new doesn't mean it can't be the cause of your problem. Did you actually swap strips?
Healthy != glitchy If you had healthy power, you wouldn't be losing it.
It sounds like this only happens when you lose power. Correct? Is it a blackout, glitch, or brownout?
You have 5 computers that display these symptoms. What do they have in common?
Same circuit? Same powerstrip? Same outlet on strip? Same model of server? Same PSU? Do you put the problem computer back in the same outlet?
Does a trouble computer display the same symptoms when plugged into a different strip or a different circuit in a new area?
If you can recreate the problem on a different "healthy" circuit then it's probably the server otherwise it's usually the strip or circuit.
Of course, it can be additive: Poor circuits + poor PSU = glitches where a better PSU or circuit will cover the weakness of the other.
Also, if you are in the US, you've got single split phase. If you're in Europe then you have two phase. Are you sure your parents have two phase? How much do they pay for that?
In Oregon, two phase is common (I know, I use X10 in my house, and have problems with the 5v powerline commands getting from one phase to the other). Two 110V wires coming in from the transformer. In the case of the X10 problem, a simple capacitor across the phases (passive coupler in a box behind my dryer- one of the few places I have 220v service) did the trick...but I bet if I had this kind of a problem in my house, I'd blow that capacitor rather quickly.
SJW: a person who perceives an injustice, and while correcting it, commits a greater injustice.
If you check the voltage between the two hot wires, you can tell for sure which one you have. If you have 208 volts between the hot wires, then you have true two phase power. If you have 240 volts between the hot wires, then your power is split single phase power.
You can't use X-10 to tell which one you have, because those signals won't cross either a true two-phase (obviously) or the transformer on a split single phase (not as obvious, but true).
If you're using a passive coupler, then I think you probably have a split single phase. The reason I think this is that a split single phase has both sides 180 degrees out of phase from each other. If you had true two-phase power, then the two phases are 120 degrees out of phase from each other. The passive coupler just passes signals, and those signals only occur at a zero crossing point. If you have true two-phase power, the crossing points don't coincide, and your passive coupler would not work.
Another indication - do you have two transformers going to your house? If not, then you've got a single transformer that has a center tap where the neutral comes from. This is how they make the two 'phases' 180 degrees out of phase.
If your parents are in a large building, like a multi-story apartment building, they still might have two-phase power, but that would be two phases of a three-phase power supply that goes to the entire building. They might notice that their electric stove takes a lot longer to cook things, because they're only going to get about 75% of the 240V power out of their 208V that setup would provide.
Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
I live in an apartment building that has three phase power. Some of the circuits are connected to one phase, the rest are connected to another phase. On occasion, one of the phases will fail and I will lose roughly half of my circuits until the power company shows up and fixes the problem.
Mea navis aericumbens anguillis abundat
Yep, that's one of the exceptions. Talked about it here:
5 00082
http://slashdot.org/comments.pl?sid=174219&cid=14
Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
There are two ways this can happen:
Note that this can be induced in otherwise properly bonded circuits by the use of daisy-chained power strips/bars. It is the act of plugging in a (typically high-power) item on the end of the line (so the draw through the whole line is high) and connecting it via a signal cable (Ethernet, serial, USB, etc.) to something plugged closer to the junction box (electrically) that then ends up routing some of the ground current through the low-voltage signal line.
In general, the cure is to return to the bonded-circuit of yesterday designated by the orange plugs where they've been installed. These consist of a single plug per circuit (never more than one!) where ground is bonded to neutral at the connection box so there is no possibility that there may be a voltage drop due to current between individual recepticals.
We seem to have gotten away from the specification and use of these (more expensive to install) power recepticals. I for one continue to specify them for most commercial installations and have yet to see any of the kinds of things mentioned here when they have been properly installed and used.
The worst case I saw of this was in an office that was long and skinny in a brand new building (they were the top floor) with retail below. The office went in first, and the retail later proved to include a dry-cleaner that used quite a bit of power off two phases of the 3.
A Unix computer in the center of the long office fed dumb terminals the length of both directions. The reception area was the farthest out - about 100' by wire - RS232 shield.
The terminal at reception kept doing wierd things: hanging, mystery characters, and in fact died - 3 times! Lights on but nobody home!
It turned out the serial interface was dieing - due to about 5 volts between ground and neutral which was pulling current through the cable's cladding and buring out the chip. The electrician poh-poh'd it saying "5 volts on a 120volt line was nothing to worry about" but in fact it was 5 volts on a 12 volt circuit and carried current in what should have been a voltage (high impedance) system. No wonder the interfaces were flaky and buring out.
Replacing the power plugs with "home-run" single bonded ones fixed the problem.
Been there, done that, paid for the T-shirt
and didn't get it
Are you sure? My understanding of the way brownouts kill equipment is that P=VI so if V drops, I increases, and the wiring is not of a heavy enough gauge to handle the increased amperage so it burns out. Shouldn't this happen in your stove, too? (Obviously, IANAEE.)
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
It is true that P=VI (actually EI), but I=E/R too.If the voltage drops, then the current will also drop, because a stove is a resistive heater. The resistance is constant. Combining the two equations gives you P=2E/R. The resistance never changes in a resistive heating element, so the power is directly linked to the voltage. Equipment that is not a resistive heater (i.e. a switching power supply) does draw more power if the voltage drops. Also, if you've got a speed controlled or governed electric motor, that will draw more current to maintain the same speed at a lower voltage.
Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
Woops, I meant P=(E^2)/R in the parent post.
Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
Did you check the inserts with your monthly utility bill to see that the energy content includes at least the specified minimum level of Microsoft-branded electricity for your Trusted Computing hardware?
I tried to turn it on, to no avail.
I unplugged it and replugged it in. THEN it turned on. And my crappy Asus card caught fire and dripped molton material on my soundcard (fortunately undamaged).
I had no cover on my case at the time as my hardware changes alot. I also had no pants -- I had just woken up and wondered why the computer wasn't on.
Computer fires with no pants are scary.
-Clio
Karma: Bad (mostly from not giving a fuck)
Blog: http://clintjcl.wordpress.com
Unplugging *ANY* computer's network cable, even for a second, and plugging it back in -- restores connectivity.
Cutting power to a hub seemed to help too. I eventually got an X10 remote hooked to my hub so I could power-cycle it without getting up.
Any clue?!?!
-Clio
Karma: Bad (mostly from not giving a fuck)
Blog: http://clintjcl.wordpress.com