Evga PSU 12V 4pin Cable On Fire- what have i done wrong

[Snail28202]

Hello All,

i am a first time builder and need some help with this as i am very confused with what happend yesterday,

First thing ill start with my setup -

CPU - Intel Pentium g3528 (with stock cooler)
MSI H81 M-P33 LGA1150 - Motherboard
REVO X1 Pro SSD Solid State Drive 128GB
AVP Hyperion EV33B Dual Chamber USB 3.0 Cube Case - Black
EVGA 500W 80 Plus Certified PSU Power Supply
Corsair Vengeance Pro 8gb (2 x 4Gb) CL9 DDR3 1866MHz Black ( i know this isnt supported on the board but i am ok with it running at a lower speed)
AMD XFX RX 460 4GB Graphics Card GPU

After i installed everything -

Everything was put together correctly, i followed all the manual, proof read everything i could prior to switching the pc on to ensure it worked, everything was brand new and the pc booted, all fans spinning, no beeps, on board audio was installed correctly, i was getting no display on the screen (i was plugged directly into the motherboard via vga rather than the graphics card as i had not installed this yet.

The problem i had -

The psu 4 pin connector 12v that connects to the cpu for power, the cables on top were getting warm, eventually i left the pc running for 10-15 minutes while i was diagnosing the issue, i then began to smell the horrible stench of the psu burning out, immediately i switched off the electricity and turned everything off, i left the pc around 5 minutes before inspecting, the 4v cable had fused with the cpu slot on the motherboard, there is no way i could salvage this as it had melted together, the cable seemed the have arced. the motherboard has now been replaced we are awaiting the psu,

The mistake i made i believe -
The 20p cable connector for the psu and the 4p cable connector were sleaved together and i could not reach the psu slot on the motherboard, i pulled on the cable with the 4 pins to ensure the 4 pin connectors could reach the psu slot, this seemed to have worked and powered the pc fine, i was getting no display what so ever when i tested but everything seemed to work fine,


The questions i have -

Is my build compatible? what did i do wrong? was this my fault or just a faulty psu? this has really nocked my confidence when building and i want to know how i managed this, are my other components ie - cpu and ram faulty now also?

Kind Regards
Joel

 

[BFG-9000]

Theoretically the 4-pin can supply 10A per wire or 240w, which should be plenty for anything not a 45nm chip @ 4GHz+

However any resistance in the connector itself will get things hot enough to melt plastic, as you've discovered, and having the same experience years ago is why I apply Deoxit to all pins. I would try to exchange both motherboard and PSU as keeping either would likely melt things again. If everything was old and out of warranty I would simply solder the wires to the board.

I've had PSUs blow up and mosfets go dead-short while stress testing with IntelBurnTest, and it has never damaged anything else. In your case you even had to shut things down yourself so it is very unlikely anything else is damaged... provided that wasn't the 4 on the 20+4 you plugged into the CPU. The CPU 12v is usually sleeved separate with only yellow and black wires and sometimes 4+4 for EPS 12v connectors. PCIe is similar looking but wired backwards and should not fit.

Just be careful next time to ensure everything is clean and plugged in tightly.

 

[Snail28202]

Theoretically the 4-pin can supply 10A per wire or 240w, which should be plenty for anything not a 45nm chip @ 4GHz+

However any resistance in the connector itself will get things hot enough to melt plastic, as you've discovered, and having the same experience years ago is why I apply Deoxit to all pins. I would try to exchange both motherboard and PSU as keeping either would likely melt things again. If everything was old and out of warranty I would simply solder the wires to the board.

I've had PSUs blow up and mosfets go dead-short while stress testing with IntelBurnTest, and it has never damaged anything else. In your case you even had to shut things down yourself so it is very unlikely anything else is damaged... provided that wasn't the 4 on the 20+4 you plugged into the CPU. The CPU 12v is usually sleeved separate with only yellow and black wires and sometimes 4+4 for EPS 12v connectors. PCIe is similar looking but wired backwards and should not fit.

Just be careful next time to ensure everything is clean and plugged in tightly.

Thanks mate, i literally turned it off within 5 seconds of the burning smell (luckily the pc was open and i was still building) i wouldnt have liked this to happen when i was asleep with my pc switched on as it could have destroyed alot more,

once again thanks for your reply.

 

[Snail28202]

So ive figured out what ive done, ive plugged the motherboard 4 pin connector into the cpu connector,

Thus creating fire, if i was a cave man i would be happy.

My fault - stupid mistake but a lesson that can be learned,

Round 2 will commense next week! 😀

 

[BFG-9000]

The 4 on the 20+4 has 12v, 5v and 3.3v plus one ground. The correct 4-pin has two 12v and two grounds, so it is possible to fry something. The wires that caught on fire likely were power connected to the motherboard's ground.