After cleaning my PC, I plugged the AC power cord into the PSU and heard the usual brief static-like sound. As soon as I pressed the power button, the cable began sparking, smoking, and burning near the PSU end. I shut the PSU off almost immediately, unplugged everything, and discarded the damaged cable. The PSU itself appears intact, and the computer currently works with a replacement cable, but I'm nervous about stressing it. The system uses an 850W 80+ Gold Gigabyte PSU with an RTX 4070 Ti Super, Ryzen 9 9950X3D, and a lightly tuned overclock. Could a partially inserted or defective cable have caused this, or should I replace the PSU as a precaution?
3 Answers
The burn location is important: if it was right at the PSU plug, a loose connection can create resistance and concentrated heat even when the computer’s total wattage is well within the cable’s rating. Make sure any replacement cord is fully seated and rated for your region and PSU, but given the smoke and visible damage, having the PSU professionally checked—or replacing it—is the safer choice. Don’t run a high-load stress test on it first.
A wall-to-PSU cable is normally just a standard IEC power cord, so it shouldn’t burn under normal load. The most likely causes are a loose or partially inserted connection, a damaged plug, or a problem with the PSU’s inlet. Don’t keep testing it just because the PC idles normally—poor connections can heat up more under load. Inspect the PSU socket for discoloration, melted plastic, or loose contacts, and replace the PSU if anything looks abnormal.
I wouldn’t trust the PSU after an AC cable got hot enough to smoke. The cable may have been faulty, but the event could also indicate arcing or a damaged socket. A new cable alone doesn’t prove the PSU is safe. Replace the PSU with a quality model, and don’t reuse the burned cord or any cable with heat damage.
That makes sense. I may not have pushed the original cable in completely, although it felt connected. I’m going to stop using the system until the PSU inlet and replacement cable are checked.