WARNING! Do not use any NON GFI transfer switch with your Bluetti product

AS you can see, I specifically asked Bluetti about a Reliance Pro/Tran 2 transfer switch and was told there was no problem using this switch.

BUT this transfer switch is not GFI switching, which means it does NOT do neutral switching like the Reliance XR series switches. I ended up frying my AC300 as a result. The AC charging circuit that was not connected to the transfer switch kept tripping every time I turned on the AC output with the transfer switch connected through the L14-30 cable. This left me with no grid charging option when the batteries fell below the PV priority UPS threshold. I posted on the community and was offered a solution; move the AC300 charging input to another circuit that was not AFCI or GFCI. The only circuit I had that was not went to the refrigerator, which had been wired into the transfer switch, so I flipped the switch to LINE and left all other circuits on GEN to pull from the AC300 and when I plugged in the AC300 charging input to the outlet - POP! no more AC300. Now it won’t do AC output or charge from any outlet because the transfer switch DOES NOT isolate the neutral on each circuit and switch the neutral like a GFI transfer switch does. Now all I have for my $3500 investment is

  1. OCP (Over CurrentProtection) - Hardware

@BLUETTI Could you PLEASE add specific warnings to users regarding the absolute REQUIREMENT that any manual transfer switch used with Bluetti floating neutral generators be GFI switching switches? OR could you make your smart panel actually available to buy? Either one would be great. I just blew up my brand new AC300 and I’m not happy about it. Now I have to do a warranty transfer just to get up and running again.

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That is really obnoxious that Winnie is saying that when there is a long thread of people having problems with transfer switches, to which @Bluetti has not been helpful:

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Hello you two,
I purchased an ep500 a year ago and have it connected with my house using a reliance r306a 30 amp transfer switch. This transfer switch runs 6 household circuits.
It sounds like i had the same ground problem that you did as i had to return 2 e500 units before i figured out a problem existed.
I normally charge my 500 with three solar panels. On overcast or rainy days I may have to supplement its charging with power from the grid if I’m not careful with my energy consumption. What I have found to be the solution is to disconnect the cable that goes from the ep500 to the transfer switch while I charge from the grid.
What this means is that in addition to disconnecting the 500 from the transfer switch I have to go to the transfer switch and turn those 6 transfer switch circuits from generator to utility power to insure those circuits will have power.
After my battery has reached a satisfactory charge percentage, or the sun’s charging state is acceptable, i unplug the 500’s charging cord from the grid (ac outlet), continue to charge with my 3 PV panels, hook the battery back up to the transfer switch and, finally, change the transfer switch circuits back to generator.
To me, this is a minor inconvenience that i am willing to deal with. I installed everything myself, including hooking up the transfer switch and solar panels and was too confused with dealing with the grounding issues. It is worth it to me because i was unwilling to pay someone for a professional install: that was a trade-off i can accept.
Good luck with your battery. I would really be interested in viewing pictures of how you both installed your units and wired them to your house.

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Just a thought on your setup @Felton: your EP500 has an “online UPS” function that the AC300 does not (“offline” only). The online UPS keeps the inverter running at all times and doesn’t use the bypass relay to power your transfer switch (assuming my understanding is correct). What that means is you wouldn’t have the grounding issue caused by the bypass.

In other words, if you switch to online UPS, you should be able to keep your EP500 plugged-in at all times and have none of these issues.

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Jason, I appreciate the info. Unfortunately I don’t want to try anything new because I’m worried about my current unit taking a dump on me if a new setup doesn’t work. Receiving a new unit and sending the other 2 units back were a big hassle. I’m not sure how much your unit weighs but the 500 is 160 to 170 pounds.
Thanks for the info though.

@Felton i also thought of your method as a compromise, but I prefer having the grid connected and letting the PV priority UPS threshold automatically pull from the grid as needed. I need to power devices for extended periods without my monitoring and intervention.

I’ve ordered the Reliance XRC0605A with L14-30 inlet. It’s a 3 Pole transfer switch to accommodate the GFCI / AFCI breakers in my main panel. It should also fix the grounding issue.

I understand your reluctance to change a working setup. I’m currently in the process of swapping my AC300 because I kept tinkering with a working system like yours.

I’m curious. What are you swapping to?

@Felton just same again. Replacing the AC300 with a new working unit

Good luck with the new unit. By the way is your transfer switch inside the house or is it an outdoor model?

@Felton the one I have now is an outdoor panel mounted indoors. The XR series I just ordered is indoor.

Ok. I have an outdoor transfer switch that I originally had set up for a tri-fuel generator. I’m curious to see how people connect their bluettis with an outdoor TS and like to compare ideas and stories.

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Birvin, how did you even get a response from BLUETTI? I’ve had the same problem, sent emails and videos and nothing. What steps did you take to get a replacement sent?

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Hope God intervenes I am finding out.

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Can I ask, if I do not charge with ac while connected to my lockout plug, will I avoid your problem?

If you do not charge with AC while connected to the panel you should have no problems as far as I know

This advice is for EU 240 volt models but the principle is the same.
Just need to keep the neutral separate between house and generator on the output circuits and ground the AC300 to earth and tie earth and neutral together. House neutral should never connect to AC300 neutral which is what happens when you charge with house AC current. Ground the AC300 to a real earth that the house grid uses.
You can use a GFI 4 pole. Connect the three L1, L2, L3 to the Hot output of the AC300. Neutral is on its own input. Not shown in picture. Notstrom is German for emergency power. Haus is House.


I don’t know what you are reading, but that response from Bluetti support does not say you can use the Pro/Tran. She clearly says that the output power from the AC300 should be isolated from the grid… both the hot and neutral. The Pro/Tran does not isolate the neutral and therefore isn’t compatible…

Please note, I’m not going to bat for Bluetti on this… they seriously overlooked the transfer switches in the market and should have provided verbiage in their manual for what transfer switches are supported and what the technical requirement are. However if you look at the schematics in the Bluetti Smart Home Panel manual it clearly shows that a switched neutral is required.

To many Pro/Tran owners are coming on these forums and say, " it works for me, so it’s fine"… but that’s far from the truth. It’s all about environment and the variables in your home setup and how you have the AC300 connected.

I’ve been working with Bluetti Engineering for the last month on this subject and I’ve been warning people left and right to not use the Pro/Tran switches… Not just because you can potentially kill your AC300, but you are in a sense you are creating a parallel power sourced system on your home electrical system by pumping two different power sources onto the same neutral system. Your grid power is completing it’s circuits on those wires and now your allowing your AC300 to complete it’s circuits on that same neutral system. And with parallel power systems they need to be perfectly in sync; otherwise you risk increasing voltage/amp, running different frequencies and cancelling each other out.

Even though the focus is on your AC300 you can ill effect other parts of your homes electricity by sending two out of sync power sources onto the same lines…

Long story short, even though Bluetti says they have fixed this issue with their new AC300’s… there is no way I would ever use the Pro/Tran. It was designed to be used in an emergency when the grid was down… not to run in parallel with the grid.


There are no transfer switches available in Europe so we make our own. However I am not transferring anything. I am setting up a UPS for three dedicated critical circuits with the possibility to switch back to normal house input to the critical circuits in the event the AC300 fails. Otherwise it supplies power all the time to my dedicated circuits.

My point is that in any event AC300 Neutral needs to be kept isolated from house Neutral.

Since there is to great a danger of confusion I will delete this after you read and my other post.

I had to return the AC300 due to 0800 error even with no load and not connected to the house. I will probably replace with EP500Pro or similar.

The circuit was shown to Bluetti EU and they confirmed the Neutral needs to be kept separate.

Thanks for your input.

Keep the post. People need to know this before they invest time/money into the wrong transfer switches and kill their systems.

And we’re saying the same thing.

@twister36 it was the

“please do not worry, you can charge and discharge through the transfer switch at the same time. The unit will not be affected.”

part that misled me. I asked about a specific model of equipment and received this answer. I’m not an electrician and words like neutral, ground and isolate don’t compute without some explanation but I am learning all I can now.