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Hello,
I'd like to connect two water pumps on one Phoenix 24/3000 and the rest of the house to a MultiPlus 24/3000. Same battery bank.
So far so good and no problem at all. BUT since Earth, Neutral and battery Negative are connected together anyways, I assume there's no issues having two separate inverters sharing their Neutral connections.
Please correct me if I'm wrong.
Sincerely, Flow
No issue with this, infact it may be a requirement of local wiring regulations.
"BUT since Earth, Neutral and battery Negative are connected together anyways..."
If you are using RCDs on the inverter outputs, the LV neutrals should not be connected to the battery negative or the earth, and this statement is not correct. If you are using RCDs, the neutrals will need to remain isolated between inverters.
You didn't say your location or application (domestic/industrial/RV?). A lot can depend on what rules apply in your location and also you installation method. I suggest you contact a knowledgeable person to do your install so it is safe.
It's a domestic installation and the only rules applying are physics here. Was simply asking for the possibilities.
For your opinion on RCDs: Please consult a knowledgeable person to give you a heads-up on how they actually work.
Regards from a professional in industrial electronics ;)
Well, I'm in the same position at the moment to make some decisions about this for my future set up.
The problem with sharing the neutral is... the size of the neutral.
If you have say 2 active (phases) for different circuits and they run on the same neutral, all is good as long as they are in sync. In this case L1 is shifted 120° against L2, so the retuning neutral will also carry the shifted currents back to wither L1 or L2.
If you operate two different inverters on such a setup, the worst case is there is no difference in phase shift and both are pushing power to your loads at the same angle. The neutral would then have to carry all the load at the same time. Example: inverter 1 delivers 5kW to one circuit and inverter 2 delivers 5kW to the second circuit, the neutral must be capable of carrying 10kW.
Only if you use synchronised inverters (same size Multis/Quattros or same size Phoenix) they will talk to each other and make sure the phase shift is 120°. This will not work with one Multi and one Phoenix.
Cheers,
Andy
Else a common N is OK even if the phases are shifted, see 3-phase installations.
No need to sync
Fideri
Plus if you have the ground relay set to be closed (connect N with PE) then both N are connected anyways.
Overload by connecting the Ns? Only if you connect the Ps as well but do not sync the inverters.....logically.
