Okay, so I recently ordered the P1S enclosure kit to convert my P1P into a P1S. I needed to print the Fan duct so I could mount the chamber fan. When I went to start the print, my printer tripped the breaker for my house. I go and reset the breaker and go back upstairs to check on my printer. It turns on fine, the AMS I have connected runs its normal filament check, and the printer looks to be working normally. However, when I manually heat the bed to 70 °C for PETG temps, the breaker trips again. This is on an arc fault/GFCI circuit. When I plug it into a non-GFCI circuit and heat the bed, it does not trip, and then I can proceed to printing. This has never happened before, and it seems to have happened after the firmware update that happened in October (Yes, I’ve been dealing with this issue for over a month with Bambu support).
I tried factory resetting it because I saw on the forums that it might help. However, when I went to start a new calibration, and it went to the bed levelling, once it started heating the nozzle, the printer tripped the breaker again. Bambu says it might be the AC board and the Heated bed, but I just checked the price, and it is expensive. The printer is no longer in warranty. I just bought the enclosure too, and now I’m torn because I could have bought the new P2S instead of “fixing” my old P1P.
Does anyone have a way to check if it’s 100% the AC board or the Heated bed? I don’t mind buying one or the other, but both make this cost similar to a new printer.
If it runs on a different circuit without tripping, the next logical step is replacing the GFCI outlet or breaker. GFCIs trip on leakage, not load, so a normal 15A circuit should handle the P1P easily given its sub-3A draw at 120V.
If you suspect the power supply, a plug-in power meter can confirm whether it’s behaving normally. These “Kill-A-Watt” style meters are generic and sold under many names:
Plus one to the thought it is probably the breaker (edit:or issue with wiring at recepticle). I suppose you could always try downgrading the firmware and see if the issue goes away. It sounds like you haven’t actually started the physical conversion so that would eliminate that haveing caused any wire abrasion or contact shorting. Did that FW update actually include “faster bed heating”?
I tried on a non-GFCI breaker and the printer did not shut off after hitting the set temperature. I just did a test and when i started heating the bed the printer was fine. I then started heating the nozzle (180C) when the bed was at around 50C and it acted normally. Once the bed temp hit 60C and the Nozzle was at 176C, the printer shut off and the breaker tripped. My house is wired weirdly, i have lights and sockets on the same breaker so there is a small load because i have the lights on but i dont think it should matter too much.
I know the last thing you want is to try a bunch of trouble shooting, you were hopeing for a solution. With what you have detailed personally I would try
Try heating the nozzle normally but with lower or no bed temp to see if breaker still trips.
Disconnect AMS and see if breaker still trips.
Downgrade firmware if 1 & 2 give no change
Is that the only circuit you have with a GFCI breaker? If you have a different circuit and it won’t affect anything critical try putting the printer on that (after all these printers are really small and light and easy to move around…NOT) and see if same thing happens.
What is the actuall FW number? I would like to look at the notes, if there are any.
Once i get home i can send screen shots of the FW and il will try the steps outlned. Im not against trouble shooting but i feel like ive done all i can to try and find or solve the issue.
So I downgraded the firmware and heated the bed only with the AMS and without the AMS, and the printer tripped the breaker at around 50 °C- 60 °C each time. Does that mean it’s a heated bed problem, or is this an AC board problem? When I plug it into a non-GFCI breaker, it does not trip, but I don’t want to run the risk of a fire if the printer is doing its job and shutting down before thermal runaway. I just want to know what to swap so I don’t spend another 200 on the printer (I could have just bought the P1P at this point and sold the printer for parts).
This is what i downgraded the printer too
Now after I factory reset the printer and ran a calibration, it tripped the breaker after it homed the printer. So I don’t know what the issue is now and I am completely lost and frustrated.
Is there an issue with using the printer in the normal 15 amp circuit? A GFCI circuit is not going to protect you from the rare possibility of thermal run away.
I honestly don’t think there is anything wrong with your printer. The circuit you are using is having issues.
I would go as far as taking the printer to another building and trying it there.
They do not need an insane amount of energy but it is much more than a phone charger or a lamp.
This would be a good test to see if it is the power supply or the electrical in your home.
Or you could try unplugging other devices that are on the same circuit. You have 15 amps to play with, but that is for the entire circuit, not a single socket.
I tried using a curling iron and a hair dryer on the circuit, and it did not trip the breaker (both of them were on at the same time). The printer was off; I was reading online that if it were an issue/bad breaker, it would trip instantly. I sent the logs to Bambu, so we shall see what they say.
Did you happen to install the P1S heat sink when you installed the enclosure upgrade? If it’s installed backwards it can short out the mains.
Check the cables in the upper left rear corner of the printer, make sure you didn’t pinch the AP to MC cable with one of the side panel screws (I’m guilty of this one).
Good thought but since the OP stated they were printing the Fan Duct so they could install the fan I would guess they haven’t started any of the swap out yet.
If you have access to a thermal gun (you point it at an object and it gives you the temp from a distance, no need to touch the bed) you can plug the printer into the circuit it doesn’t trip, let it warm up and read the temp and see if it stabalizes where it is suppossed to. It it keeps climbing you can just unplug the printer.
So, have you actually started any of the conversion process yet? It really seems like the issue is not the printer and the no errors generated seems to support that but I can understand your frustration and hesitation. To stress test the circuit with something else you would probably need to use something like a plugin heater, one of the older models, the kind with the hot wire and fan in it.
Edit: From what I see the printer can draw up to 1000w when heating the bed, then it drops off once temp is reached.
Sorry for the barage of edits, the FW notes don’t indicate anything about changeing the bed heating process.
I have not started the process yet as I’m waiting to get this issue fixed.
I read that on the Wiki and will be mindful of that when I go to install the new one. Regarding the MC to AC cable, I will check that and see if I can notice anything out of the ordinary. I haven’t touched the wiring since I got the printer, now 3 years ago. It would be a shame if the life span of the parts is only three years. I keep the printer in my office, and it’s well ventilated. I do maintenance every year to make sure it runs as smoothly.
