PSU tripping breaker when plugging in

WonVinegar · January 16

Two months ago, I got a Corsair RM1000X Shift (ATX 3.0 version) with the Corsair sleeved cables, and I ran into an issue where my breaker tripped right when I hooked up the PSU to the outlet (It was switched OFF). I thought the PSU/cable set was defective so I returned it and ended up going with a RM850X Shift (ATX 3.0) and have been using it for over a month now with the stock cables.

I decided I wanted to swap the cables and try the Corsair sleeved cables again, so I got the cables, cable managed them a bit with some cable combs, and swapped them in and used it for a day with no issues. After a day or so, I tried to manage the cables a bit better. With the PSU switched OFF, I plugged in power again but it ended up tripping my breaker just like it did a month ago with the old PSU that I thought was defective and returned. This PSU has been fine so of course I assumed its the new cables, so I tried to straighten each pin a bit more after that and made sure it didn't bend too much after that. It's running fine now, but I'm still a little concerned.

Does anyone know what might cause something like this, and should I be concerned with anything? I 3D printed the combs, and I was trying to get some on that were a bit tight, so I did end up clamping the cables a bit. I ended up not using them though, not sure if that caused some damage or something. I'm not using them anymore and there's no visible damage to the cable anywhere that I can see, no sharp bends either.

It's on a standard 120V 15A breaker, and I didn't have anything really high powered running at the time in the room. It's never tripped in my day to day aside from these few times. Also don't think it matters, especially since it was powered off, but my components definitely don't pull over 850W either (9800X3D and 2080).

Needfuldoer · January 16

What else is plugged into that same circuit? An 850 watt power supply by itself shouldn't trip the breaker. (Unless it's a GFCI or AFCI that's miswired or doing its job.)

A short on the low voltage side of the power supply shouldn't cause it to trip the breaker.

mariushm · January 16

If the power supply is turned off using the on/off button in the back , then plugging the AC cable in the connector shouldn't do anything because the on/off switch disconnects everything from the connector.

If the computer is off by the on/off switch in the back is still in the on position, then when you plug the cable in the power supply some components inside the power supply will start to charge up with energy and will draw some power. There's a couple high voltage capacitors which are charged fast, and that will cause a spike of current, up to 30-40A of current, but for a few milliseconds. The fuse in your electrical panel should be the right kind rated for 15A or more, so that the fuse won't trip when you have that 30-40A spike for a few milliseconds. I don't want to go as far as calling them "slow blow" or "time delay" fuse, because standard electrical panel fuses should be designed to tolerate more than 15A current for very short periods, but if you have to I suppose you could use slow blow fuses in your panel.

When you plug the AC cable in the power supply, you also have a somewhat imperfect contact until the cable is fully plugged in, so you could have for microseconds at a time spikes of current and sparks in the connector. To reduce these sparks and damage to the metals, it's always best to turn off the power supply from the switch before inserting the cable in connector.

A power supply provides 5v stand-by 24/7 for as long as the on/off switch in the back is in the on position. So if the on/off switch is on the on position and you plug cable in, the 5v stand-by portion of the psu will automatically start to draw power and give 5v stand-by to the computer even when it's turned off.

A short circuit in the cables going to components won't cause a problem on the mains, on the high voltage side. A controller chip in the power supply detects such issues and sends a signal to the primary side of the power supply and the power supply shuts down.

WonVinegar · January 16

6 hours ago, Needfuldoer said:

What else is plugged into that same circuit? An 850 watt power supply by itself shouldn't trip the breaker. (Unless it's a GFCI or AFCI that's miswired or doing its job.)

A short on the low voltage side of the power supply shouldn't cause it to trip the breaker.

Quite a few things, but they were all off or on standby at the time pretty much aside from lights (The major things would be a TV, 2 monitors, 4 powered speakers, game consoles, a dozen or so LED light bulbs). Definitely would be weird if these caused it since I’ve had everything turned on before no problem.

5 hours ago, mariushm said:

If the power supply is turned off using the on/off button in the back , then plugging the AC cable in the connector shouldn't do anything because the on/off switch disconnects everything from the connector.

If the computer is off by the on/off switch in the back is still in the on position, then when you plug the cable in the power supply some components inside the power supply will start to charge up with energy and will draw some power. There's a couple high voltage capacitors which are charged fast, and that will cause a spike of current, up to 30-40A of current, but for a few milliseconds. The fuse in your electrical panel should be the right kind rated for 15A or more, so that the fuse won't trip when you have that 30-40A spike for a few milliseconds. I don't want to go as far as calling them "slow blow" or "time delay" fuse, because standard electrical panel fuses should be designed to tolerate more than 15A current for very short periods, but if you have to I suppose you could use slow blow fuses in your panel.

When you plug the AC cable in the power supply, you also have a somewhat imperfect contact until the cable is fully plugged in, so you could have for microseconds at a time spikes of current and sparks in the connector. To reduce these sparks and damage to the metals, it's always best to turn off the power supply from the switch before inserting the cable in connector.

A power supply provides 5v stand-by 24/7 for as long as the on/off switch in the back is in the on position. So if the on/off switch is on the on position and you plug cable in, the 5v stand-by portion of the psu will automatically start to draw power and give 5v stand-by to the computer even when it's turned off.

A short circuit in the cables going to components won't cause a problem on the mains, on the high voltage side. A controller chip in the power supply detects such issues and sends a signal to the primary side of the power supply and the power supply shuts down.

Having the PSU switched off before plugging in the AC power cord is something I always do, and I would always switch it on afterwards. What you mentioned about imperfect contact sounds like a possibility since I was plugging it quite slow. I’m also not exactly sure what you mean by “If the computer is off by the on/off switch in the back is still in the on position”. In my case, the power supply was switched off using the on/off switch on the back.

zeldanerd12344 · January 17

i have had a similar problem after "updating my drivers" and a braker trips on the psu two or three time but if I just my pc sit off for like 30 min that fixes it for me My psu is the corsair cx 750 maybe that will help next time it happens