A friend recently helped me try to replace the power supply on a PC I was recently given. My original/current PC was having Hard Drive issues. The new PC (a Sony) was set up in such a fashion to make it impossible to fit the new power supply in the correct spot. The friend gave me a 3rd PC to use in the mean time.
So after he left, I attempted to reinstall the power supply to my original PC. I recalled which cables connected to the Hard drive and studied the pin pattern on the other cables and connected them in the seemingly correct spots: the 4 pin plugs to each of two cd/dvd drives, 20 pin to mother board, a 2x2 4 pin to a second spot on mother board, and the 4 pin which I knew went to the hard drive. Also reconnected the cable from harddrive to motherboard. (I was using the “new” harddrive from 2nd pc to test it.) The only cable from the power supply left unconnected was a small adapter on the same strand as the CD/DVD drive cables. I assume its for a non-existant floppy drive. And I’m fairly certain that I saw such a cable hanging freely when I first opened the PC.
The 3rd PC in the mean time has been hooked up to my monitor (LCD TV), and running a data recovery scan on the original hard drive. Not wanting to disturb the 5 hour scanning process, I plugged in my original PC with its recently replaced (original) power supply near the tv. I used a second socket. I unplugged the monitor cable from the back of the PC running the scan (leaving cable connected to tv), and tried to plug it into the other PC. Sparks flew from the monitor plug as soon as the cable touched it. It tripped the breaker to that outlet, luckily a different breaker than the one the scanning PC was on.
Now, I live in an older home (100 yrs or so). I know from previous electrical work on the house that some of the outlets may not be grounded it the fashion current standards dictate.
Is it possible that I connected something incorrectly in the PC, and that any attempts to plug it in elsewhere will result in damage/electrocution? Or is it more likely an issue with an improperly grounded outlet? It seems unlikely to me that anything I connected would result in electrical arcing from the monitor connection. But I don’t want to risk further damage or injury. Also what is the likelyhood of having fried components in that PC now? Motherboard? Hard drive? RAM, Video card?
In case that was unclear, it essentially boils down to:
My PC’s power supply was completely removed. A new(ish) harddrive was installed. The PC power supply was replaced. I’m fairly sure all cables are in the correct spots, but I’ve never replaced a power supply. I plugged in the PC and connected the monitor cable which was already connected to TV. Sparks flew and tripped breaker. Slight black mark on monitor connection point.
It’s usually pretty difficult to misconnect a power supply, since the majority of connections are keyed so plugs won’t fit into the wrong sockets. Was the original PC a Dell, by any chance? The older Dells, at least, used proprietary power supplies and motherboards that used the same connectors, but different pinouts, so mixing and matching Dell and not Dell power supplies and motherboards is usually fatal (to the computer).
Unfortunately, if enough current went through the system to trip the circuit breaker, the motherboard, power supply and video card are almost certainly fried, potentially the TV as well. The rest of the system may be okay, but there’s a pretty good chance that everything else may be fried too.
Does the power supply have a 110/220 switch? Is it switched the appropriate voltage? (110 for US)
I burned out a motherboard once by having that switch in the wrong position. That was some years ago on a cheapo power supply, don’t know if it could happen with modern equipment.
The power supply was originally from that PC (it was only out of it for a day or so), so I don’t think a 110/220 setting is the issue. The monitor is fine. It was plugged into a GFI outlet and was DEFINATELY grounded. The outlet the comp was plugged into was very possibly not grounded. The PC was off, but the monitor (tv) was on. Would the mixing of a grounded monitor and ungrounded (and off) PC cause arcing?
And more importantly: if I plug the PC into a grounded outlet, do I not need to worry about a repeat performance?
This problem is CLEARLY a Hot to Ground short.
You need to confirm that both outlets are wired correctly. Period.
You also need to confirm that neither piece of equipment has a primary to secondary short (i.e. - both power supplies are isolating the wall voltage from the chassis of the pc/monitor).
Ok. I will cease using the problem outlet until repaired. The LCD TV power supply shouldn’t have an issue. I will recheck the connections on the PC power supply, but as I stated: although I’ve never connected one before, all of the wires that I connected plugged into what appeared to be the only available slots that each of them fit. I’m fairly certain that the ones NOT plugged into anything never were plugged into anything. So there shouldn’t be a short there, correct?
Connections from the power supply should be idiot proof. The connectors won’t attach the wrong way because the plugs are asymmetrical. If there is a short in your PC, it may be your mobo is touching the case somewhere. More likely something has gone wrong in the power supply circuitry itself.
it is a hazard to use 3 prong receptacles in an ungrounded situation. if the wiring to a receptacle location is ungrounded then you should use a 2 prong receptacle.
if a 3 prong receptacle was used in an ungrounded situation then a fault could cause the case of an appliance to have lethal electricity on it.
some devices need to be grounded to work correctly.
you have a hazardous situation that needs to be looked at.
It doesn’t matter.
If your Power supply is NOT defective, you could cut off the end of the cable, strip all the wires, and put them anywhere you want in the computer, and all you will do is blow the fuse (and possibly damage the computer). A properly functioning power supply will NEVER allow mains voltage to appear on the secondary side, which means there is nothing you could have done to cause this problem - it is clearly something defective. Either an outlet (ground connected to Hot), or a bad power supply (Hot-ground short, with ground disconnected).
I’m positive I put that in correctly. I triple checked the key shape on both sides before inserting.
But Beowulff sounds to be knowledgable and confident of the situation. So I feel better about it and more comfortable. Thank you so much to Beowulff and the others who responded for your input!
Most likely, agreed, but you’re supposing that the PSU is not defective. If the PSU is a cheap-and-nasty job then I would be very wary about saying that the PSU was not defective. I have learned this the hard way.
True, but if the PSU was defective (primary to secondary short), then it really wouldn’t make any difference whether the cable was plugged in correctly or not, the chassis would still be hot with respect to ground.
You didn’t qualify the size or sound of the spark, and you didn’t describe the type of circuit breaker, so it’s hard to tell for sure what’s going on.
Was is a large spark that made a ‘bang’ or was it a small spark like putting metal in the microwave that makes a ‘crack’ noise?
Does your breaker box have arc fault, ground fault, or simply current based tripping breakers in them?
If it was a big spark with a bang, then Beowulff is on the right track, you don’t have a power supply connection issue…it seems like one outlet is wired with hot and neutral switched, and possibly some hack tied the ground terminal to the what is supposed to be the neutral wire. (assuming you’re in a country with a TN-S power system)
I’ve seen sparks generated by USB headers plugged in the wrong way around, so I’m not so sure about that. But we’re talking about a case that the OP has definitely excluded, so it’s not profitable to continue.
A lot of the wiring in the walls, including that outlet was all knob and tube originally, with lots of junction boxes everywhere. The breaker box (and fuses) according to an electrician who looked at it was pretty new and definately not on the lower end. To the best of my knowledge the breakers are all simple current based. I know they are NOT arc fault.
The spark was quite large, and I would have described it as a POP or a loud CRACK. The spark was not a little, “oh that might have stung” kind of spark. It was more like a, “HOLY MOTHER OF GOD, I’m glad that didn’t touch me” kind of spark. The kind that makes you think you narrowly avoided electrocution.