The PSU frequently trips the 5A plug fuses?
The PSU frequently trips the 5A plug fuses?
Hey there, this is my first encounter with something similar. In the UK, our plugs contain fuses inside.
Here are the details:
- PSU: Dark Power 13 750W
- Motherboard: MSI Mag B550 Tomahawk Max WIFI
- CPU: AMD Ryzen 5 5600x
- GPU: Radeon RX 6800XT (Powercooler Red Devil)
- RAM: 2x16GB Corsair Vengeance LPX
I assembled a new PC last August and it functioned perfectly until this weekend. I used it normally, turned it off, and then after about 30 minutes it refused to power up again. When I checked, the 5A fuse in the PSU's connector had blown. I replaced it, but it immediately blew again—probably a mistake to make later.
I always connect the PSU to a surge protector. There was no sound or noise at all. None of the capacitors on the motherboard appeared damaged. I haven’t overclocked any part of the system.
The only possible reason might be...
Our power plug has a small on/off switch. I don’t use my fingers to flip it under the desk; instead, I lean back in my chair and tap with my foot. It’s not very precise, and sometimes I keep the switch halfway for a few seconds before switching it on and off quickly—this could be what happened when I turned it off.
I haven’t taken the PSU out to run the paperclip test. While it seems safe, you can’t just throw paper clips into electronics without thinking. It’s a real hassle removing the PSU for testing.
My next steps are: file a return, purchase a replacement, or see if I can still use it safely—depending on how bad it is.
I’m also curious about checking the other components. Unfortunately, I don’t have a proper test setup, and the only tool I have is a multimeter.
Any tips would be greatly appreciated.
Cheers.
Test the PSU with the multimeter. It should not require removing the PSU; just check via the connectors.
https://www.lifewire.com/how-to-manually...er-2626158
This isn't a complete test since the PSU isn't underload. Any voltages outside tolerance raise suspicion about the PSU.
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It's normal to use a foot to switch off power strips or surge protectors, but this should be avoided.
The risk is higher with cheap switches; they might cause current surges that blow fuses, trip smaller breakers, or damage devices.
Remember, surge protectors are rated in Joules and their protection is limited. A single big surge or repeated smaller ones can make them ineffective.
So, another source of surge could be affecting the PSU.
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What caused you to flip the power switch? Are you using the Windows shutdown process to turn off the system and then switching the power to the PSU?
I would try the paper clip test to activate it, ensuring you obtain the correct pins and unplug it from the wall and remove it beforehand.
I’d also connect some devices such as a case fan or an old hard drive to apply a light load. Check if the fuse remains intact.
I’m concerned about other parts too—like a faulty motherboard or graphics card, which could cause this issue. However, I believe the PSU should shut down before the fuse blows, according to what I understand about UK outlets. If it trips the fuse before the PSU activates in a fail-safe mode, there must be something grounding that shouldn’t be.
Lifelong habit.
It's probably worth clarifying for folk outside the UK that
it's the switches on the mains socket
I'm turning off with my foot, not the power switch on the PSU.
When shutting my PC down I use Windows's shutdown procedure, and a few seconds after my PC shuts down (after the lights go off and there's a soft audible click), I turn off the power switch on the mains socket.
Unless you unplug the PC/PSU to plug anything else to the wall outlet there's no need to turn the plug/socket off. Neither the PSU, there's no need to turn it off between use as some users do that.
First thing I'd unplug everything (24-pin, 4+4-pin, PCIE auxiliary etc) and take the PSU out of the case. To isolate it from PC components and to test with papterclip or multimeter. I'd add a load to the PSU if available when doing papercliip test, like a molex fan.
Have you tried plugging anything else in the outlet? If it blows with other appliances too maybe the socket has a short, a loose connection, damaged pins, caused by corrosion etc.
Have you tried turning the PSU switch off and then turn the socket switch on? I would take PSU out now (if you haven't already) to test this so the PC is not connected to a possibe faulty plug or PSU. Do this and if the plug/socket fuse blows once you turn PSU on maybe the inrush current from PSU Off > PSU Standby trips/blows the fuse. There might be a short in the PSU too. Like PSU's own fuseable components. I hope no component after PSU is damaged.
I can verify that both the outlet and the surge protector are functioning properly.
During troubleshooting, I moved my PC to another room and noticed the fuse blowing at a different outlet (still using the same surge protector – though I’m not sure if that’s the problem).
Thank you for all the feedback and advice so far. I’ll test the PSU tomorrow with a clear mind and will get back to you all.
Just to confirm, was the surge protector between the PSU and wall outlet/adapter every time you tested in the same and another room (after it stopped blowing fuses)? This is because these surge protectors have been known to cause problems with PCs and PSUs. If so, to rule out the protector, try connecting the PSU directly to outlets or adapters without the surge device.
the make and model of the surge protector is unclear, but it seems to be misleading; I've used one before, but it didn't match your description.
just to confirm, usually the surge protectors inside the plugs work well. however, this doesn't guarantee the actual surge protector can manage the load effectively. cheaper surge protectors might be able to handle it better.