Multiplus External Ground Relay control Does not Work

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Yusef Neblett asked Jun 17, '20

Multiplus External Ground Relay control Does not Work

Hi Victron,

I have a SplitPhase Setup with an 48/5K 230v Multi + Autotransformer. The setup Manuals tells you to Disable the Multi+ Internal Ground relay by removing the check mark in VE Configure.

and that will enable the External Ground relay control at the Multi+ to use the Ground relay at the AT.

Multi+ gnd relay connection

I realized this AT external ground relay does not close at all. So I tested the relay applying 5volts and the relay close (Relay has a label attached that said 28VDC). Then I tried to read anything coming from the Multi+ Gnd relay green contact and nothing is coming out (no voltage, no Contact close)

I tested having the Multi in Inverter mode and connected to the Grid and the same results.

Multi+ Firmware: 473

Additionally, I tested changing the dip switches has the Manual advise and still no control over the AT gnd relay.

Thanks for your help

Grounding Autotransformer

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wkirby answered · Jun 17, 2020 at 05:57 PM

To make the external ground relay work, you need to set the Ground relay check box and then select external ground relay, SW1 ON.

Clearing the checkbox will disable any ground relays, neither internal nor external ground relay will work without the box checked.
The switch chooses which ground relay, either internal ground relay or external ground relay.

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pciccone commented · Jan 06 at 03:51 AM

After countless hours of trying to figure out what was wrong your answer also saved me. I cannot understand why the AutoTransformer documentation is still incorrect even now in Janurary of 2024 referencing to turn off Ground Relay. The correct answer is as you stated and to NOT turn off Ground Relay and turn on SW1 to trigger the external ground relay. Victron - PLEASE fix the documentation. You are wasting peoples time with bad info.

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Answer 1 · 2020-06-17T18:18:52Z

Yusef Neblett answered · Jun 17, 2020 at 06:18 PM

Hi @WKirby

Thank you so much for your quick and clear explanation. Will be good that the Manual explains it in the same easy and understandable way.

I just tested and it works beautifully.

Thanks

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