EPS/UPS from batts/hybrid inverter

[AE-NMidlands]

Hello all
My Givenergy inverter datasheet has a section about its backup terminal. Says:

Nominal AC output power 3600W
Nominal Voltage 230Vac
Max output current 16A
nominal frequency 50 Hz
Automatic switch time 10 ms
THDv (linear load) 3%

Given the elaborate independent earthing requirements for systems running in off-grid mode, are there rules about how this can be used? Or is there a dispensation for just 1 socket run off it? 3600W is the full output of the inverter! If there is an automatic switch-in, then does there have to be an automatic switch-over to a separate earth? and if so, how would it be sensed as relying on comms from the inverter wouldn't seeem to be fail-safe!

[Adokforme]

That's an interesting question @AE-NMidlands as I have a similar set up and yet to sort the EMS side so would be keen to find out what is involved as presently we sit here with circa 75 kWh's of storage and no means of utilising it during a power cut.

[Tinbum]

I can't find it at the moment but SMA do a publication on this, with a design of a switch over.

It's not just about the actual earth but also switching the Neutral earth bond as well.

It all gets very complicated especially with EV chargers as well.

Edit page 16 onwards https://files.sma.de/downloads/SI44M-80 ... -en-10.pdf

[AE-NMidlands]

I can't find it at the moment but SMA do a publication on this, with a design of a switch over.

It's not just about the actual earth but also switching the Neutral earth bond as well.

It all gets very complicated especially with EV chargers as well.

A bit off-topic, but do we have neutral-earth bonds, or is it something the DNO has? My earth is (and always has been) a thick wire soldered to the exterior cladding of the incoming cable which goes to my Henley block.
I'm sure I haven't got a bond as it would have stopped me getting a tingle off the neutral in the past!

[Adokforme]

I can't find it at the moment but SMA do a publication on this, with a design of a switch over.

It's not just about the actual earth but also switching the Neutral earth bond as well.

It all gets very complicated especially with EV chargers as well.

Cheers @Tinbum. Your post reminds me that when we had V2H unit installed we had to put a fresh earthing point in for the entire bungalow so V2H, Car Charger and property were all on the same earth to aviod the complication of potential touch points between them. Or, is this not what you are refering too?

[Tinbum]

page 16 onwards https://files.sma.de/downloads/SI44M-80 ... -en-10.pdf

[Tinbum]

A bit off-topic, but do we have neutral-earth bonds, or is it something the DNO has? My earth is (and always has been) a thick wire soldered to the exterior cladding of the incoming cable which goes to my Henley block.
I'm sure I haven't got a bond as it would have stopped me getting a tingle off the neutral in the past!

Earthing is very complex when you actually look at it. Worth doing a Google of all the different types.

I don't understand it all myself but I do know that their are requirements regarding earth neutral bonds. The link does show how neutrals have to be disconnected. I'm pretty sure their used to be a requirement that their could only be one earth neutral bond in a property but I think this possible was dropped recently.

[Tinbum]

also https://files.sma.de/downloads/SI-OffGr ... -en-11.pdf

[AE-NMidlands]

also https://files.sma.de/downloads/SI-OffGr ... -en-11.pdf

Thank you, those look like what is needed... "just" a case of establishing exactly what your situation is and what you want to do!

Once again, if we do our homework properly, we shall know more than almost any surveyor or even sparky that we try to get to help us!
(A non-technical lady friend in her mid-70s with pv and a FIT said to me this morning

"The 'surveyor' they sent knew less than me. Couldn't answer my question about the bigger battery - thought my electricity bill would show our current consumption, which is only consumption from the grid. I think they are set up for new solar systems and not tagging a battery on to an existing [PV system]. His function was to photograph the posssible installation location"

[Tinbum]

Once again, if we do our homework properly, we shall know more than almost any surveyor or even sparky that we try to get to help us!
(A non-technical lady friend in her mid-70s with pv and a FIT said to me this morning

Often the case. I bought a battery off a solar installer a couple of weeks ago and he soon realised, as soon as I said I was going to alter the CAN messages to get it to run on a different make of inverter, that I knew more than him.

I've been suffering with really bad Long covid for the last 4+ years and I have been having to look at research papers etc. I now find I know more than a lot of the Dr's and consultants at times. Last Monday I corrected the GP about vitamin B12 testing, levels and deficiency but it was like hitting my head against a brick wall for what it was worth. I just hoped she had a conscience and looked it up when she had a bit of time. To be honest it's awful what I have been finding out about the way the population is hoodwinked. I had a phone call from my Cardiologist a few weeks ago and many of the questions I asked he simply didn't know the answer, ignored or fobbed me off. I have a loop recorder and even questions on what data he could see at my last consultation on his screen and how it was processed were avoided.