Main switch earth leakage tripping when inverter changes over unless solar panel earth is disconnect

**Pieter00** · 13-Dec-21, 04:51 PM

Good day, i got called out to a victron installation with the following happening:

The main switch of the home is a three phase earth leakage. the input to the inverter is on the line side of the earth leakage which is correct. the output side feeds to a sub main switch with an earth leakage feeding the plugs in the property as per regulations. but when the Grid goes down and switches to the inverter, the three phase earth leakage trips out and has to be switched on again by hand. There is a surge protections device installed on the AC side of the inverter and the PV panels also has an earth that is connected to the same surge AC surge protection device as no DC surge protection was installed. when i disconnect the earth from the solar panels, the tripping problem goes away. My question is, will the installation of a DC surge protection device for the solar panels stop the earth leakage from tripping or not? as the DC earth and AC earth still has to be bonded together anyway?

**GCE** · 13-Dec-21, 05:21 PM

You say the inverter is on the line side of the ELU which also acts as the main switch .

If that is so , than how do you drop power to the inverter ?

Trying to understand the set up

**Pieter00** · 13-Dec-21, 06:46 PM

they have a separate 63A single pole C/B installed near the inverter feeding the inverter input along with the changeover switch and output C/B. the remaining two phases that is not on inverter backup supplies the stove, geysers etc.

I recon there should might be a voltage on the panels between + and earth which can be traced but if its something in the settings of the Victron, then ill have to walk away unless there are any other suggestions i can look at? i doubt that it can be cause of no DC surge protection as the DC earth and AC earth is all bonded together anyway

**Justloadit** · 13-Dec-21, 07:04 PM

Originally Posted by Pieter00

There is a surge protections device installed on the AC side of the inverter and the PV panels also has an earth that is connected to the same surge AC surge protection device as no DC surge protection was installed. when i disconnect the earth from the solar panels, the tripping problem goes away. My question is, will the installation of a DC surge protection device for the solar panels stop the earth leakage from tripping or not? as the DC earth and AC earth still has to be bonded together anyway?

Where is the Earth to the PV panels physically connected to?
The frame, or to one of the PV panel wires (Positive or Negative)?

Alternatively there is water somewhere along the PV wires, maybe a disconnect box, or a junction box. If this is the case then itcould be dangerous, firstly electric shock, secondly an arc may arise from the DC and cause a fire.

Check this site for more
Solar fires – DC arc faults

**Dylboy** · 13-Dec-21, 07:10 PM

Hello

I do not know Victrons inverters.

But its a premium inveter so my guess is that it would internally switch and join the inverters output N to the E as to bond it.

So when it goes into Islanding mode the output N and E are bonded. But when the grid is on then that bond is broken.

So I feel that may be a cause of the tripping is that switching.

So my remededy or attempted remededy would be to chnage the ELU. To get the client to now pay for a 3phase ELU as a "lets see if this works" is another issue.

If it always worked before and only now giving issues then I do believe a ELU change is in order. Also if it is a CBI one I am reading and catching wind of them failing or become too sensitive from all the load shedding.

Anyway if you so find the answer please do let us know.

Now this is a total guess but perhaps if there is a new applience plugged in that may have electronics in, the capacitors and chokes and all may push the ELU over when there is a switch with leading, lagging of currents and dips.

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**Pieter00** · 14-Dec-21, 11:13 AM

Alright this was kinda interesting. apart from the solar installation, the client also has a backup system for his geyser with a pc board in the db allowing the sun to heat up the water and if it's inadequate to reach the required temperature, it also takes from the grid the power it requires and it also has a bypass circuit breaker. when i bypass this pc board and switch off the grid to the home, the inverter changes over fine and nothing trips but when the pc board is not on bypass and i switch off the grid, it trips out the main switch which is the 3 phase earth leakage. So he is getting the guys out that did the geyser installation and he was so happy that he now wants 3 solar quotes on 3 of his 10 game farms urgently whoop whoop!

**Justloadit** · 14-Dec-21, 05:23 PM

Originally Posted by Pieter00

the client also has a backup system for his geyser with a pc board in the db allowing the sun to heat up the water and if it's inadequate to reach the required temperature, it also takes from the grid the power it requires and it also has a bypass circuit breaker.

What make and model?

**Dylboy** · 14-Dec-21, 03:31 PM

Thats brilliant! Congrats on those opportunities to quote!

Also thanks for the feedback! Intresting and well found on that issue !

Something to keep a note on for future.

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