question

mindaugas avatar image
mindaugas asked

ESS Multiplus 2 error 8 if Out2 Neutral is connected to common neutral

ESS Setup:

Multiplus II 24/3000/70, Cerbo GX, MPPT 100/50, SmartShunt, LifePO4 210Ah 24V batteries

The issue is that Multiplus gets an error

Error 8: Ground relay test failed on VE.Bus System (Multiplus)

This is only when Neutral of OUT2 is connected to common Neutral busbar

If all sources of OUT2 are on separate neutral bus this error does not occur

According manual I haven't found any requirement to separate neutral on OUT2victron-setup.png

Multiplus-IIESSerror
victron-setup.png (67.1 KiB)
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1 Answer
wkirby avatar image
wkirby answered ·

If you use a common neutral then you will be bypassing the relays and then their tests will fail. The relay will appear closed when the test is expecting it to be open. This is one of the reasons for having a separate neutral.
Also a common neutral means that you are only disconnecting one live conductor from the network since the neutral conductor is permanently closed via the common busbar. You should be disconnecting both live conductors (line and neutral) when AC-IN is not present.

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