Solar wye/wye transformer


Senior Member
Northern CA, US
Electrician, Solar and Electrical Contractor
I wonder if Solaredge needs the nuetral for communication between the inverter and the optimizers.

Does anybody know how their optimizers and inverter communicate? I assumed it was through frequency. Its only DC homeruns. I find that quite interesting that the inverter can pick up the optimozer serial numbers through the pos and neg homrun circuit. And that the serial numbers must be embedded into the oprimizer (DC converter) somehow.

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PE (Electrical), NABCEP certified
Austin, TX, USA
Electrical Engineer - Photovoltaic Systems
Nope, that's all on the DC side.

I don't think Solaredge really needs the neutral but maybe they think they have a reason not to say so.
Maybe so; I don't know. What I do know is that I am obligated to install equipment according to manufacturers' instructions, and theirs says to install a neutral, so I do.


Senior Member
Do you have an example of any utility scale inverters that are currently made today, and require full size neutrals? And is it just lack of a statement otherwise that causes them to require it, or does it actually have an operational reason for a significant amount of amps on the neutral?
All of them I am aware of, at least the UL listed ones for the USA. If the manufacturer has not stated that a reduced size neutral is allowed for a specific inverter then a full sized neutral must be used. I am not aware of any large MMW inverter manufacturers who have stated that reduced size neutrals are allowed. If you have access to an installation manual for one of these inverters that says a reduced size neutral is allowed please let me know who the manufacture is and the inverter model. I would like to know.