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ispookie666 avatar image
ispookie666 asked

RCD Tripping randomly

I have just about installed Multiplus 48/1200/13 and hooked it up to Li-ion 14s1p batteries.

It has been working perfectly in UPS mode and pass through. To test the capacity, I turned off the mains and the UPS kicked in, I let the system run - till the cut off voltage was reached.

When I turned on the grid/mains - the RCD (on the mains consumer unit) tripped. It did this a few times. I disconnected the load and the same happened (rocker switch in ON position). Then I switched it to charger and it did not trip.

I tried various combinations and unfortunately - the RCD tripping is very random and not reproducible.


AC in comes from the grid

AC out goes to feed a total of 250W (a few pumps)

Any input or help would be appreciated.

MultiPlus Quattro Inverter ChargerGeneratorGrounding
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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ commented ·

A system wiring diagram would help with the troubleshooting.

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ispookie666 avatar image
ispookie666 answered ·

Wiring diagram - Hope this makes sense


If the low voltage does not kick in(when I don't let the batteries run low) - the system functions perfectly; UPS kicks in and auto transfer works perfectly and the Multiplus charges the battery.


But if the Multiplus shuts down due to low voltage and if the mains come on, the RCD on the main consumer unit trips - If there is AC Load connected. Without any AC Load the RCD does not trip. This situation continues till battery voltage is above low battery voltage alarm.

I have a feeling its something very simple I have over looked.



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jwfrary avatar image
jwfrary answered ·

Can you give us a photo of your mains consumer box.

I’m wondering if you have a rcbo and your not tripping on a ground fault but a current.

Also the obvious check your wiring for chafe, or stray strands at the connections etc.

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ispookie666 avatar image
ispookie666 answered ·

The RCD which trips is the one on the left.


As I mentioned in the subsequent post - this only happens when Mains power is restored after Multiplus shuts down due to low battery voltage and with mains pass through.

If it was a fault in wiring, I would have thought the RCD would trip regardless.


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ejrossouw avatar image ejrossouw commented ·

Is the multi case earthed and how? In a fixed installation, you only need use the earth from the ACIN and ACOUT. Also don't discount a faulty RCD.

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ispookie666 avatar image ispookie666 ejrossouw commented ·

It is a fixed installation and the Multi case is not earthed(I hope you are referring to the earth pin on the case, at the lower end). The ACIN is earthed as normal from mains, and the ACOUT is wired as required including the earth.

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klim8skeptic avatar image klim8skeptic ♦ ispookie666 commented ·

It is a fixed installation and the Multi case is not earthed

This is not the reality, please be more forthcoming with information.

Neutral to earth leakage will also trip RCD's.

You have a multiplus compact, unplug the output to check downstream ac wiring.

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ispookie666 avatar image ispookie666 klim8skeptic ♦ commented ·

Like I said, the downstream circuit on itself does not trip RCD, it was in this configuration for a few years.

I recently added Multiplus and that's when it tripped (only if the low.battery has caused the inverter to shut down)

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ispookie666 avatar image ispookie666 klim8skeptic ♦ commented ·

I guess I did not put it correctly. I have not connected the chassis ground to anything.

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ejrossouw avatar image ejrossouw ispookie666 commented ·

Yes, thank you. I was indeed referring to the case grounding as below.

"- In a fixed installation, uninterruptable grounding can be secured by means of the grounding wire of the AC input. Otherwise the casing must be grounded."

At least we have eliminated one more possibility.

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ispookie666 avatar image ispookie666 ejrossouw commented ·

I'm sorry.. I did not follow you.

Should I connect the ground to earth of ACIN?

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ejrossouw avatar image ejrossouw ispookie666 commented ·

If the installation is fixed in e.g. your house, then there is no need to earth the MP case as stated in the manual. In a boat or RV etc, the MP case has to be earthed via the separate earthing terminal on the case. The ACIN and ACOUT however all have to have all three lines (L,N,E) connected. Your connections appear fine.

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ispookie666 avatar image ispookie666 ejrossouw commented ·

Many thanks for clearing this out.

It is a bit strange that the RCD tripping only happens when mains come back on after the Multiplus has shut down due to low battery voltage

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bruces avatar image
bruces answered ·

Please give details of where this install is located?

Country?

House, boat, motorhome etc?

Installed by licensed electrician? (who knows local regs.. MEN etc)

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ispookie666 avatar image ispookie666 commented ·

Country - United Kingdom

Installation - Home (static)

Installed by myself - the N E L on ACIN and L E N on ACOUT, and the batteries are Yuasa LEV40 14s with a DALY BMS (the tripping occurs even without this BMS).

I have added the Grid code in VE BUS

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ispookie666 avatar image
ispookie666 answered ·

I Added a DPDT relay to provide dual source of power to my critical equipment - I was able to consistently create the RCD tripping. When the Multiplus was in the inverter mode and the backup power(Separate mains power) came on but the Multiplus input AC was off, the RCD kept on tripping. I guess this points to N to E linkage problem.

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ispookie666 avatar image ispookie666 commented ·

Managed to circumvent this by adding a second DPDT relay for the Neutrals (victron output and backup power).

After all this, I believe - when the Victron shuts down following low battery, the N to E link is not broken, causing the RCD to trip when the mains come back.

I'd really appreciate if anyone can verify if this is what is expected.

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tedr avatar image
tedr answered ·

Have you tried to disable the "Ground Relay" setting?

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Carlos Carvalho avatar image
Carlos Carvalho answered ·

Still facing this issue? I am having this exact problem

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tedr avatar image
tedr answered ·

I have solved the problem with better connected Earth Spike. There was a bad earth connection. Now my neutral and earth are at the same level.

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