ideal setup for 3 Phase 208V 43.2KW SolarEdge Inverter 175-200 OCPD

electrofelon

Senior Member
I'm not really arguing with anyone. I just can't get the better of my curiosity. The post you quoted was a series of genuine questions, for you or ggunn. They remain unanswered for me.
I am with you. I also would like a response from noob or gunny about 230.40 ex 2 vs supply side connection. I keep saying it can be essentially the same thing but all i get is "no" without any specific response with reasons as to why I am wrong. Is it whether that set of SEC is serving only PV stuff? If so does adding a recep or ight turn it into 230.40 ex 2. Then as WW said, seems you get the benefits of supply side without it being one.
 

electrofelon

Senior Member
Correct. I am leaning toward a 400A service disconnect outside and 300A main breaker. Thanks!

So I am going to use a transformer to go from my 240 Delta to either 208Y or 277Y. I can get inverters for both voltages with the 277/480 being cheaper. See any reason to go 208V? I suspect the transformers are similar in cost.
I would first look at inverters compatible with your existing service and not using transformers.
 

ggunn

PE (Electrical), NABCEP certified
I am with you. I also would like a response from noob or gunny about 230.40 ex 2 vs supply side connection. I keep saying it can be essentially the same thing but all i get is "no" without any specific response with reasons as to why I am wrong. Is it whether that set of SEC is serving only PV stuff? If so does adding a recep or ight turn it into 230.40 ex 2. Then as WW said, seems you get the benefits of supply side without it being one.
If the AHJ sees it as a line side connection, that's what it is as far as they are concerned and what I think doesn't matter. The systems I deal with are clearly line or load side connected, one or the other; I haven't tried to push things into a gray area and argue about it with an AHJ. I probably won't.
 

electrofelon

Senior Member
If the AHJ sees it as a line side connection, that's what it is as far as they are concerned and what I think doesn't matter. The systems I deal with are clearly line or load side connected, one or the other; I haven't tried to push things into a gray area and argue about it with an AHJ. I probably won't.
Oh come on, take one for the team! Jaggedben and I want to know!
 

hevnbnd

Member
There are other inverters out there.

Do you run your solar plans by the poco?
Correct there are. However I want to use SolarEdge.

Have not talked to poco yet. Was working with them getting a total for changing from 240 delta w/ high leg to either 208V or 480V. Since I got a price of 15K I will be working with what I have which is the 240V delta and using a transformer. Will be sending them over my plans on Monday. Attached is what I am planning for now.

Solar Electrical Schematic.jpg
 

electrofelon

Senior Member
Do you know of a 240V native three phase inverter? Offhand, I don't, but I don't know every inverter in the world.
Fronius symo line I believe does it. I was even thinking he could use single phase inverters (depends on what poco would allow of course on a high leg delta, might be at their mercy). 3 15kw fronius primo would do it. They do 1kv strings too.

But if the OP is set on solar edge with transformers, so be it.
 

ggunn

PE (Electrical), NABCEP certified
Fronius symo line I believe does it. I was even thinking he could use single phase inverters (depends on what poco would allow of course on a high leg delta, might be at their mercy). 3 15kw fronius primo would do it. They do 1kv strings too.

But if the OP is set on solar edge with transformers, so be it.
He may be dealing with a rapid shutdown issue.
 

pv_n00b

Senior Member
I am with you. I also would like a response from noob or gunny about 230.40 ex 2 vs supply side connection. I keep saying it can be essentially the same thing but all i get is "no" without any specific response with reasons as to why I am wrong. Is it whether that set of SEC is serving only PV stuff? If so does adding a recep or ight turn it into 230.40 ex 2. Then as WW said, seems you get the benefits of supply side without it being one.
I went and looked up the utility's exact requirement and this is it:

SOLAR PHOTOVOLTAIC SYSTEM SHALL TERMINATE ON ITS OWN AC BREAKER IN THE MAIN SERVICE EQUIPMENT EXCLUSIVELY.​

That's how they prevent supply side interconnections. The definition of "Main Service Equipment" is not provided. I've only worked on a couple of commercial projects in the area of this utility and they were both load side interconnections. In another area, they would have both probably been supply-side interconnections. One required reducing the size of the main breaker from 800A to 600A to free up ampacity for the PV system and the other required an alternative means exemption from the AHJ to interconnect to a switchboard in excess of 120% back feed.
 

wwhitney

Senior Member
I went and looked up the utility's exact requirement and this is it:

SOLAR PHOTOVOLTAIC SYSTEM SHALL TERMINATE ON ITS OWN AC BREAKER IN THE MAIN SERVICE EQUIPMENT EXCLUSIVELY.​
That raises the question of how they apply that rule when there are two main service equipment enclosures.

The wording also permits line side taps via an MLO service panel, but of course that may not be how the utility applies the rule.

Cheers, Wayne
 

beanland

Senior Member
Transformer Loss

Transformer Loss

Using a transformer to change from one voltage to another has penalties/costs. There are 24x7 no load losses and load losses proportional to the square of the load. These both eat into the energy produced by the PV. Losses vary all over the place, the cheaper transformers likely have the higher losses. If you can use inverters with no transformer, you can get around those losses.
 

pv_n00b

Senior Member
That raises the question of how they apply that rule when there are two main service equipment enclosures.

The wording also permits line side taps via an MLO service panel, but of course that may not be how the utility applies the rule.

Cheers, Wayne

I think that they wrote up the interconnection instructions with residential use in mind without thinking about other types of services. Around here residential services just have one main service panel and disconnect. I don't think they put a lot of thought into it.
 
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