GFCI Breaker trips when powering on two pcs at the same time but not when staggered

Question

I have two pcs. One pc connects to TV, and stereo. The other to three monitors (may be worth noting it has a 3090, and with the new world gpu bug that drew too much spike power would trip the breaker on its own, consistently).

If I turn on both pcs (and their associated devices) at relatively the same time there is a decent non-100% chance the breaker will flip. If I stagger the two pcs and their associated devices it appears to be fine so far. I have honestly not tried to spike power draw the 3090 since the new world bug (as I don't want to overly stress the expensive card).

Could someone help explain what is potentially going on and how to fix or reinforce the setup to resist the issue better?

Added info: The 3090 pc has a ups, and one surge protector for less important things. The TV pc has one surge protector for everything. There is another surge protector but is essentially doing nothing (powers led light and charges phones very rarely).

Edit (Crip659): There is no light on the GFCI Breaker, just a little button and then the switch.

Edit, additional info: No AC, AC is a duct based AC on its own. Items connected to:

• 2x 31 inch monitors
• 1x 27 inch
• 1x pc w/ 1000watt psu (w/ i9 and 3090)

The above is on one ups

• 1x orbi router

• 1x surfboard modem

• 1x smart home hub

The above is on one surge protector

• 1x LG TV 45 inch (ish)
• 1x 500 watt psu w/ i7 / 980ti
• 1x audio receiver

The above on one surge protector

• 1 led lamp
• 1 USB for phone charging

On one surge protector

• 1 led lamp
• 1 curtains automation

On one outlet (two different spots..)

The gfci appears to only trip if too much is turned on at once, or back when my gpu flew to the moon due to a game bug that near bricked 3090s. Avoided that game after that issue, so just appears now when two pcs and their associated items are turned on within short order of each other.

Never mentally calculated the draw, but I think I will now label each machine and compare it to what the breaker says is max. I don't run both machines greater than 3 hours, so I don't think I would have 80% load for extended periods (1 hour for sure though).

The 3090 will play graphical games, but the 980 is just more of an overblown media center. Though my issue appears when they are turning on near the same time (within a few minutes, waiting 5 or so minutes seems to be the sweet spot to not trip anything - it also doesnt appear to happen everytime so... really makes me scratch my head).

The breaker that handles all this is a 15A GFCI Breaker. (Handles lights and outlets for the master bedroom and bonus room, and just lights for the bathroom, bathroom outlets have their own dedicated breaker).

Answer 1

Check if the GFCI breaker is tripping for GFCI or for overload.

GFCI trip?

Video cards don't trip GFCIs because they don't connect to AC power. Every PC has a "Power Supply" which adapts 120/230VAC mains to the low voltage the PC requires.

The power supply is the only component in a PC which is capable of tripping a GFCI. There should be no leakage between AC mains hot+neutral and any of AC mains ground, chassis, or any of the DC lines being serviced.

It would be typical for a power supply to be faulty in a way which it only ground-faults at higher power ratings.

I would expect a single PC to trip a GFCI

Overload?

GeForce RTX 3090 Ti: You’re gonna need a bigger boat (and power supply)

Yeah. You can't just dogpile unlimited amounts of stuff onto an electrical circuit. Two gaming PCs and accessories is a lot... and if you're tripping breakers you're adding at least 6000-8000 BTU of heat into the room so I bet an air conditioner is among the loads.

You need to look at equipment nameplates (everything has a nameplate) and look at the AC-side power requirements in amps, watts or VA. (Watts and VA are similar; divide by voltage to get amps). The circuit breaker has an amp limit stamped on it. You must not intentionally install loads which exceed that limit. And if loads are continuous (run over 3 hours), don't exceed 80% of the breaker limit. That is your responsibility.

I advise checking each machine and putting a label on it indicating the number of amps. Don't run things together that exceed your breaker capacity. And remember your PC area may not be the only loads on the circuit! It may serve other rooms too.

Gaming PCs can be notoriously power-hungry. And typically they add so much heat to the room (6000-8000 BTU if you're tripping the breaker) that someone adds an A/C unit also. So this creates a recipe for overloads if the person is negligent about overloading the circuit.

So, crunch the numbers, label your equipment... and if the numbers are saying "this just doesn't work, I can't run the stuff I need on this circuit", then contact an electrician to run an extra circuit or three. (not that much harder to run 3 cables than 1, the hard part is getting access to the route.)

They don't generally make single circuits bigger (it's not worth it). Regular household circuits are 15A or 20A. Upgrading to 20A makes no sense, because that would mean removing the 15A wire, and you might as well just leave it in place and have both a 15A and 20A circuit side by side. So you can power 35A of stuff instead of 20A. And like I say once the person has opened up the wall to add 1 cable, they might as well add 2-3 and then have 55A or 75A usable. Most houses can handle this load because of how 240V works.

Do not use a larger circuit breaker. The circuit breaker size matches the wiring in the wall, and enlarging the breaker will overheat that wiring.

Answer 2

More troubleshooting ideas:

Make sure the UPS input fault lights are off. Not even a faint glow.

Try swapping out both power cords for the computers.

Try performing a GFCI test using one of those cheap outlet testers with the GFCI button on it.

Try running the same loads on a different circuit.

Check the power rating on the audio receiver. With the 1,500 watts of PSUs plus the capacitors in the audio amplifier coming online all at once, an overload is not out of the question.

Try unplugging everything and then run a 12-amp power tool and see if that works normally.