Manual says “This product must be grounded before operation”.
None of my other Bluetti models have this Caution.
Why does this model need a ground, how to go about doing that and does Bluetti supply a cable with this model, since it is apparently Mandatory.
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Just talked with customer support and they said the ground is not needed - they will be updating the user manual for AC180
After confirming with the technician, AC180 can be used without grounding.
Grounding would be safer or some loads require grounding. Grounding is required by safety regulations.
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For Bluetti Support - My AC180 is 240VAC AU with grounding screw. If I plug in a portable Earth Leakage Circuit Breaker (RCD) to one of the AC outlets of the 180 and a device into the RCD, I ask 2 Qs.
- Will the RCD trip offering shock protection in the event of a fault?
- Do I need to ground via the screw or not for the RCD to work?
I also own a AC200P (purchased Oct 2023) it does not have a grounding port. Would the RCD trip on the 200P in the event of a fault? Or do either unit have internal circuit breaker short circuit protection?
Although I can use both units in a residential environment, the AC200P is for home use, the AC180 for RV (caravan) use
- If the AC180 is connected to the grid, grounded and also in bypass mode (not providing output from battery) the answer is yes.
- If your AC180 AC input cord have the ground pin, you don’t need to also use the ground screw. Otherwise you should ground the unit by using the ground screw if you would like point 1 to work.
Be aware that the unit automatically manage the AC output source, so you cannot always assume that the unit is in bypass mode for the RCD to detect an N/L phase loop from grid to earth and therefore disconnect the load.
- Yes, it requires grounding screws to be grounded or connected to the grid.
- If RCD is to be used for AC200P, manual grounding is also required.
- Both devices have short-circuit protection.
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To understand the AC200P & AC180 internal wiring, one further Q.
Is there any connection, internal to the 2 units, between the inverter output Neutral and the earth pins? i.e. are they bonded?
FYI, I am in the process of making up a couple of earthing solutions for my needs.
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AC180, when off grid, an Earthing cable with a cable lug on one end to fit to the 180 earthing port (screw) and a connection to an earthing stake to ground.
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AC200P, a “suicide” extension cable - with a 3 pin plug top on either end. However, the Active wire will not be connected to either plug top and therefore never live. Understanding the internals will assist as to whether I connect the Neutral wire or not.
This cable can be used at home, plugged into a house 240VAC socket and use the home grounding connection on one end. The other end will be plugged into one of the the AC200P 240VAC outlets. The 2nd outlet will have the RCD box plugged in as it has 2 GPO outlets. If the internals are the same for the AC180, this cable will also work in a similar way.
I understand that the AC*** outlet, earth sockets are linked to each other internally.
No, there is no bound from any live to the ground internally to the units because:
- that could result in a dead short in case of a ground failure on any of the devices connected to AC output
- that will result in a electrical hazard in case of a single wire insulation failure since those units are configured to be portable and not to be used as a main service for a house, and so they are not equipped with an RCD by default
- that is complicated to manage safely since the power can be supplied by AC input which is already bonded to ground too by default and that will create a loop
Your plan can work as a way to ground everything together to filter out energy spikes and EMI, but the RCD on AC output will not work when the unit will be providing power from the inverter, so to me it doesn’t sound reliable.
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If you really want to protect everything with an RCD from the Bluetti as an UPS you should:
- unbind the house grid neutral from ground
- only connect the grid to AC input
- bound the AC output yourself to ground, before any RCD
- ground your devices
But, at this point and before to supply any power, you should consider that you now have the grid in AC input and the Bluetti bound to ground on AC output: the problem here is that the same grid could be used by your neighbors and:
- your neighbour could be grid-bonded to ground too: you will have a loop from Bluetti AC input and AC output from the soil which is naturally a conductor
- your neighbour could have a device or machine with a low insulation: you will have a loop from Bluetti AC input and AC output for the same reason
Either way, without a proper dielectric isolation from the grid you will risk to create a loop and to permanently damage the device. That is possible only on completely off-grid systems.
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As another way, if you want to power the house while being off grid and not charging the Bluetti at the same time, you can keep the grid isolated using a double transfer switch for both phases to avoid any error (you should switch house input, ground and grid in a certain order). In this case the Bluetti will only power the house, grid will be completely isolated and can keep its original bond on the main service disconnect, and any RCD on AC output will always work if the Bluetti will be correctly grounded and bonded to ground (before the RCD).
Even if this mode can work, also note that:
- when switching back to charge the Bluetti, ground on AC output should be lifted first
- while in off-grid, an incorrect ground or a lose ground or a non-working RCD will automatically result in a electrical hazard in case of a single earth failure
- it’s dangerous
At the end, I think a portable power station should be used as a portable power station or, if powering the house is really important, forget about RCDs since Bluetti is floating grounded and a shock hazard is possible only on double insulation failures.
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That is a lot to digest, I’ll try to make my Q as simple as possible. But first, at no point did I state “bond from any live to earth”. I referred to the Neutral Earth Bond or floating neutral.
Scenario 1. My grid system goes down due to a weather event. I setup my AC200P, plug in my home refrigerator/freezer into it to run during the power outage, independent of the grid.
The AC200P has no mains connection to earth as the power brick feeds the unit via a D7909 2 pole plug and would not be used anyway. It has no UPS function or indeed an earthing pole like the AC180 has. The 2 fault issues I would envisage are, 1. A fault internal to the AC200, in which case, I would imagine the internal circuit protection would trip. 2. A fault in my refrigerator, which is not earthed.
So if I connect the fridge to one AC200 outlet and plug in an earth cable only to the other, my fridge is now earthed as the 2 outlets are linked.
To reiterate, There is no Grid AC input to the AC200P. It is taken out of storage to use only as backup power, not connected via any switching to the grid. The fault scenario is to primarily earth the appliance. I should note, if I’m in a blackout, the whole neighborhood usually down.
Having said that, if my fridge does fault, would an RCD between the AC200P outlet and fridge detect an imbalance and trip, without a neutral earth bond?
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The point is, the neutral is the term that refers to a live that is bonded to ground, Bluetti being floating grounded has 2 lives and no neutral.
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I understand what you’re trying to accomplish and not judging you, in the opposite I respect your attempt to reach the maximum level of safety, my argument was to take it a bit farther to explain a bit about the whole grounding situation with portable power stations in general since I understand this is a very underrated and little known topic.
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Your answer is: no, the RCD connected to the AC output will not detect a single insulation fault to ground.
You have to imagine the voltage as a difference of potential between the two wires, since we’re talking about AC current that’s sinusoidal and so alternating between the two wires in a harmonized way. To imbalance this current by touching one of the two wires you must act as a bridge between them, ground is just a term that refers to this bridge.
An RCD detects this imbalance only when part of the current that’s leaving the RCD get imbalanced after it, but for this current to actually get imbalanced from after the RCD it need to flow back to a point before the RCD, that’s why a phase is grounded before the RCD, this way if one phase touch ground the ground itself will act as a media to allow this current to flow back before the RCD and allow it to detect an imbalance because some current is returning to the inverter/source without passing through the RCD itself.
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On your case, by having a fridge directly connected to the AC200P, you have to understand that in case of a fault an electrical hazard will not be possible in any way. Even in case of a serious compressor fault with one of the two phases touching ground and so the metal structure of the fridge. In that case by touching the fridge yourself there will be no potential difference between you and the fridge because you will be touching a phase that has no way to return back to the AC200P inverter and will be completely isolated.
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That’s basically the opposite of what happens in every movie where people get randomly electrocuted in water. An electrical hazard is only possible when current is flowing trough you and that could happen only if you act as a (conductive) bridge between 2 phases. Touching 1 phase and ground will not have any effect if the other phase is not actually grounded to allow the soil to complete the connection between this other phase and you.
That’s why on floating ground devices there is no electrical hazard in case of a phase to ground fault on any device. And on double phase to ground fault there is no hazard anyway since that is basically a short that will throw a fault on the inverter. If you are using an RCD that is not pure (RCBO) and also has over current protection that will probably throw at the same time as the inverter. In any case, you will have the AC output automatically turned off.
To get electrocuted by a floating ground device you should be so unlucky to get yourself into the situation where you are touching both phases at the same time, and that is extremely unlikely to happen except if you are messing with the device.
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About the grounding itself of either AC200P power supply or AC180, that is most useful to allow the devices to disperse to ground any current spikes or electromagnetic interferences coming from the grid. That can happen in case of grid operations, faults or lightning storms.
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I finally got to my multi meter, dam rain lol., I did a continuity check on both units. What I found;
AC180 - Grid supply cable earth pin is grounded to all other ground pins i.e. the 2 inverter 240VAC outlets and the earth port (screw) i.e. pass through. Neutral and earth have no continuity and therefore floating. This answers my Q re this unit, if the supply cable is connected to the grid regardless of it being down due to an outage, the AC180 is earthed and so are appliances connected to it that have an earth connection. The screw needs an earth connection of used in a mobile situation i.e. RV use. However,
AC200P - There is no earth input from the power brick and no earth port. Both inverter 240VAC outlet earth pins are linked and there is no neutral earth bond. Which takes me back to the “suicide cable” being used to at least earth the appliance. (Only the earth wire connected at each end of the plug top). I find it counter intuitive to link the earth pins internally with no designed way of ever using them externally.
It would be really helpful if Bluetti provided specs in the manual stating it is a floating neutral inverter and what earth points if any are interconnected.
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Ndwr, Thanks, that I do understand :) with regard to the AC200P. It’s sounds a bit like hanging from a high tension wire being relatively safe so long as one is not grounded.
However, my next Q, is the AC180 internal inverter the same or similar to the AC200P in concept and if so, why does it have an earth connection?
If it is used as an UPS, it has through earthing common to the input, outputs and earth port, is this why?
Then, if it used standalone not connected to the grid why have the earth port? Or, should it be grounded to an RV chassis? I understand some jurisdictions require earth by regulation. I believe Australian RV regs are changing re this for new RVs in this country. Fortunately not retrospective.
Quoting myself.
The AC180 and AC200P inverters are completely different, by only the first one being bi-directional, but they pretty much share the same filtering methods and that is why ground is recommended in case the unit is connected to external incoming power sources (grid by internal or external power supplies, or solar panels for example) that they could potentially drive unwanted transients to the unit (i.e. lightining).
About why the units have ground internally connected between output plugs, screws or inputs that is to avoid the buildup of unwanted differential currents between device shields and metal surfaces, that is to provide an equipotential grounding method of leveling out static electricity for example.
So, to answer to your question grounding is always recommended for these reasons.
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Thanks, will take that on board re RV use. :)
Thank you. I have a 750W Bluetti I have solar charged and used extensively for 5 years, and a new AC240. And have been astounded at the lack of info the latter came with. And all the weird ports, But I need the bigger one for my off grid work now that I am working alone and from an electric van, The AC240 is mounted in my eTransit. My 750 can be carried around and powers my fridge and lab equipment, but the 70 lbs AC240 needs to make me comfortable, to save driving power for the van’s driving range. So it is crucial I get the grounding right, as I do not want to mess with the van’s batteries.
When I draw 110 V I get a grounding error, so I assume I need to drive a spike into the dirt, right? I had also hoped I could draw from its 220V plug, but it is not standard. So what is up with that? Why are alll the USB such high wattage? and what is a Power Bleed?
Is someone going to write a User Friendly manual for this AC240 Bluetti ? (made by Shenzhen Poweroak) I hope so, because I have a lot of research in remote places to finish this summer. And not enough time to look for a better explained solar generator.
I hope someone can advice me Thank you.