Generator hook up to Multiplus 2 10kva, floating neutral question

DIY
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1

Good morning

My current setup is fairly basic, I have a 10kva Multiplus 2, MPPT 250/60, Cerbo and a 32kwh battery, all supplying my house in a hybrid off gid operation.

My question hinges around the generator hook up. I have a Honda 32i suit case petrol generator (I believe is a floating neutral type generator) that I have connected to AC input on the Multiplus for use in an emergency.

I’m a bit confused over information suggesting I fit a Neutral to earth bonded dummy plug in the spare power receptacle on the generator.

I understand that the Multiplus internal ground relay will open when it sees a generator input and as such my house RCDs will no longer operate as desired?

My questions are - is this correct that the RCDs will no longer work in the house if I connect up a running floating neutral type generator?

Is fitting the N-E bonded dummy plug best practice? Will it work in ensuring my house RCDs are back in service and is there any possibility it could damage my Honda?

Many thanks

2

With an inverter type generator I would NOT fit a Neutral - Earth bond without express recommendation from the manufacturer.

One way to check this would be to measure the Neutral / Earth voltage from the generator wiht no other loads connected. If this is ~50% of the nominal AC voltage, then it will be unsafe to fit a neutral ground bond.

Operation of RCD’s when on generator: possibly they will not operate, and just pushing the test button on the rcd will NOT test this - one would need an external tester. However, with a floating neutral/live setup, then a single fault (L/E, N/E) will not pose any risk, as there is no return path for the current. IF the generator is producing a biphase output, ground referenced, then the RCD’s will operate normally.

3

Thanks Mike. Appreciate the helpful reply.

I’ll test the Honda output today and see what the results are.

Again, many thanks :+1: