Try the system on a different outlet that is on a different circuit just to make sure it is the system. Also try an outlet that is not on an AFCI breaker. And yes AFCI breakers can go with no warning. I have seen it happen more than once. Also have a look at this web page and this one for more information on AFCI circuits.

Next step is contact Dell tech support and have them decide on the course of action. 

Thanks for the reply @JOcean. I read the 2 links you posted and in one the problem was solved by a new AFCI and the other by a new PSU.

Just got the PC yesterday. I'm afraid to turn it on and I don't really want to try it on other non AFCI circuits because the other circuits without AFCI cannot detect arc fault.

I will contact Dell in a bit. I'd rather have a different PSU that doesn't trip my AFCI. Are they known to do that (replacing the PSU)? It's definitely the R11 because of the tests I did. I hadn't even started any game when tripping happened (was just installing some apps like 7-zip and a pdf reader).

I'm now using my old gaming pc and haven't had any issues.

Yes, both AFCI and GFCI wear-out (especially if you use them a lot or heavily).

First sign that they are wearing out is that they become over-sensitive and trip without anywhere near max load.

There was a similar thread a while back. New GFCI combo-outlet/breaker fixed it. 

Load has nothing to do with either GFCI or AFCI tripping, as the protection they provide is always present regardless of the amount of the load.

GFCI detects current leakage to ground by measuring the current that goes out versus what returns. If what returns it less than what went out, the difference leaks to ground somewhere in the circuit. If the leakage is high enough, typically in the mA range, it will trip the circuit. 1 mA is 1 thousands of an Ampere.

AFCI detects an arc fault by listening for noise on the power line, typically around the 100 Khz range for more than a few milliseconds. That would normally indicate an Arc happening somewhere in the attached circuit.

There are 3 types of AFCI breakers:

- Branch feeder. These are the oldest, mostly phased out by now and replaced by dual function AFCI. Detects parallel arcs.

- Combination AFCI. Detects both series and parallel arcs.

- Dual function. Detects both series and parallel arcs, and ground fault. Basically an AFCI and GFCI in one breaker.

Without further troubleshooting your issue I cannot say what you have going on, but if I were you I would try that circuit with another load and see if it trips. It's possible you have a bad socket, or a loose wire somewhere in that circuit and each time you put a load on that circuit it arcs at the bad connection point and trips the breaker.

If it trips with another load, It can be very dangerous and cause a fire. I would highly recommend to have an electrician check out this circuit and make repairs as required as opposed to keep using.

If it does not trip with another load the circuit is likely ok. In that case, if you have a combination it could be due to ground fault or arc flash detection. If you just have AFCI, than it will be due to arc flash detection. That could be due to a bad connection somewhere in the computer circuit, likely the power supply. Please ensure the power supply cable is all the way inserted into the power supply. They sometimes require some force to go in all the way.

You could also have an issue with powerline noise on that circuit, causing an "incorrect" arc flash trip. That could indicate a bad power supply.

thanks for replying. I have the branch feeder type of AFCI by GE. I don't have GFCI on this circuit or on any outlets on the circuit.

you said: "... if I were you I would try that circuit with another load and see if it trips."

I've done it several times. I never had problem with this circuit and I've been living in the current place for 7 years. I have a space heater, hair dryers, computers and monitors, and speakers plus an xbox series x and a PS5. Not all of them were turned on at the same time of course, but when they were they were all working fine.

I also tested turning on / off a 1400W hair dryer with space heater set to 78F (not baseboard but a portable unit plugged into an outlet on the same circuit) and with my old computer + monitor ON an hour ago. No problem at all. So no load problem. 

I'm a heavy user and I have lots of stuff plugged in and turned on at the same time on this circuit. So I agree with you this must be an Arc problem (tripped when only the R11 and a monitor plugged in). The problem is, it's this R11 causing arc. Likely the 1000W PSU not doing the right job and is a potential fire hazard.

Thanks speedstep. It was a 15A AFCI protecting both my room and my bedroom that got tripped, so I know it's not being shared with kitchen appliances (those are on a different circuit). It tripped even when only this computer and a monitor were plugged in on the circuit (not outlet, but the entire circuit in both rooms). 

I also tested all the outlets on this circuit with a similar device like the one you show.

Not trying to be rude or mean but I only see a few options

1.try it on and circuit preferably with the ups.

2. Be ready to pay for a service call if it turns out that Dell sends a tech and the power supply does not fix it.

3. Return the system.

I highly doubt that Dell will even send a tech without testing another circuit. 

Nope, I don't feel you're being rude or anything. I've read online that these powerful PSUs do sometimes cause problems that trip an otherwise fine AFCI.

I'm not inclined to try it on a different circuit. The reason is simple - I need this computer working in my room. I'm not going to use it in the kitchen. And not in the living room and not in the batnroom.

If Dell doesn't want to do anything, then it's fine too. I will just return it. I just don't think asking a customer to upgrade his home electrical system in order to use a computer is the right thing to do. Like I said several times on this thread already, I never had any problem in this room (on this circuit) with a lot of different devices turned on at the same time.

UPS is not designed to detect arc fault. UPS has battery and protects against surge. This is not a surge condition. This is arc. Arc got passed through to the breaker. It’s the PSU.

Is anyone else bothered by the fact that when it was plugged into the UPS it happened but the UPS didn't seem to care?

I could be wrong but if the UPS isn't having a problem with it wouldn't that point at the outlet? 

Just want to point out the issue might be as simple as a loose connection on the actual outlet you are using for the R11. That's why I was wondering if you had tried another load on that specific outlet? It sounds like you have tried other outlets on the same circuit, but not necessarily that specific outlet.

It is also possible it is the power supply causing noise on the power line, causing the AFCI to detect it as an arc fault and trip. The power supply would normally have a noise suppression circuit, but it's possible it does not function properly. They are switching power supplies, but designed not to put noise back onto the grid.

I did. I plugged the computer in 3 different outlets and it tripped the breaker every time. One of the outlets has a UPS with my old computer and monitor, and the other 2 had other devices (floor lamp, air purifier, speakers, router) plugged in to them too (devices -> surge protector -> outlet).

Thanks for replying. I tried everything. I’m just not going to test the computer with a GFCI outlet in the batnroom (in-suite, but on a different circuit with GFCI outlets) because it does not make any sense. I always use a UPS with computers and monitors and UPS will trip GFCI. UPSs are not designed to work in environments that require GFCI outlets (plain fact). On the other hand, I have had 2 UPSs on this AFCI protected circuit and they never caused any issues.

All the outlets in the room are on the same circuit. The lone 15A AFCI protects 2 rooms (this one and my bedroom). I do not have another AFCI circuit in the house to test the computer on.

If at least one of those outlets is on a different breaker even if it is the same type that should be a good enough test to confirm that it is the computer.