Solar ready service

Status
Not open for further replies.
Ponchik

Ponchik

Senior Member
Location
CA
Occupation
Electronologist
I understand that a solar ready panel comes with a kit that gets installed on the line side of the service disconnect. if you take the same panel that is solar ready vs one that is not solar ready, is there any difference in the rating of the buss?

I assume by doing the line side connection, the main service does not get derated, am I correct?
 
Ponchik said:
I understand that a solar ready panel comes with a kit that gets installed on the line side of the service disconnect. if you take the same panel that is solar ready vs one that is not solar ready, is there any difference in the rating of the buss?

I assume by doing the line side connection, the main service does not get derated, am I correct?
Click to expand...
If the PV interconnection is on the line side of the main service disconnect, the bus rating of the panel is irrelevant.
 
So what types of solar ready products are manufacturers offering? Just curious I'm not familiar with them. Are these for line side connections where they have spare lugs on the line side? Or is it something that comes with a larger bus, say a 225 amp bus and a 200 amp main breaker for a load side connection?
 
ggunn said:
If the PV interconnection is on the line side of the main service disconnect, the bus rating of the panel is irrelevant.
Click to expand...
So I make sure that I comprehend:

If the service panel is not solar ready, then the main service breaker has to be derated based on the back feed amperage of the solar system.

If the service panel IS solar ready, I don't worry about the derating because the solar back feed connection is on the line side of the service breaker.
 
electrofelon said:
So what types of solar ready products are manufacturers offering? Just curious I'm not familiar with them. Are these for line side connections where they have spare lugs on the line side? Or is it something that comes with a larger bus, say a 225 amp bus and a 200 amp main breaker for a load side connection?
Click to expand...

Found out some info after my original post:
If a 200A service panel is solar ready, then the buss is rated at 225Amps.
 
Ponchik said:
So I make sure that I comprehend:

If the service panel is not solar ready, then the main service breaker has to be derated based on the back feed amperage of the solar system.

If the service panel IS solar ready, I don't worry about the derating because the solar back feed connection is on the line side of the service breaker.
Click to expand...
When you say "solar ready" I think you are referring to the typical meter/main (150 or 200 amp) that has a provision for an additional line side breaker of, typically 50 amp max, that can be used as a line side solar tap point. This is by definition a PV line side tap and bus size is irrelevant.
If you tap your PV down stream of the main then then it is a load side tap and bus derating may be applicable depending on various factors.
 
'Solar Ready' is a marketing term with no precise code or technical definition whatsoever. Read labeling and diagrams on the actual equipment and don't make assumptions or try to make a rule out of it. Some have essentially an additional service disconnect, others have higher rated busbars, etc. etc. We cannot tell you which it is from the general term.
 
jaggedben said:
'Solar Ready' is a marketing term with no precise code or technical definition whatsoever. Read labeling and diagrams on the actual equipment and don't make assumptions or try to make a rule out of it. Some have essentially an additional service disconnect, others have higher rated busbars, etc. etc. We cannot tell you which it is from the general term.
Click to expand...

I am not assuming or making any rules out of it, At least I dont think I did. I am asking for clarification so I can understnad what i"Solar Ready" is.

I understand it now.
 
Ponchik said:
I am not assuming or making any rules out of it, At least I dont think I did. I am asking for clarification so I can understnad what i"Solar Ready" is.

I understand it now.
Click to expand...
Eaton seems to use the "225A busbar, 200A breaker" ((70A solar) approach for their "solar ready" products. Looks like siemens does that too, but also has some line side connected devices for higher PV inputs.
 
Honestly, with the proliferation of solar, all the busbar's should be rated for back-fed breakers of at least 60A.
 
Ponchik said:
So I make sure that I comprehend:

If the service panel is not solar ready, then the main service breaker has to be derated based on the back feed amperage of the solar system.

If the service panel IS solar ready, I don't worry about the derating because the solar back feed connection is on the line side of the service breaker.
Click to expand...
No. "Solar ready" or not, if a PV interconnection is on the line side of the main service disconnect OCPD, the rating of a panel/busbar on the load side of the MSD is not relevant. "Solar ready" has nothing to do with it.

Look at it this way: the service conductors can typically deliver hundreds or thousands of amps to the line side of the MSD; whatever additional current a PV system adds doesn't make an appreciable difference.
 
Like some underwear, depends™?

Gonna put my foot in my mouth, but never stopped me before.

ggunn and jaggedben assuredly more knowledgable.

Been using the Handbook© (NEC 2020 currently). More Better, imho.

Size of the solar array kinda relevant. Lots of % parameters involved, Overcurrent/buss rating/etc.

(DEFINITELY) Might wanna check out Article 705.

.11 (Supply-Side Source Connections) & .12 (Load-Side Source Connections), good a place to start as any. The Handbook may/May not have additional pics, definitely (probably) 'explains' more. WHY i started using it. AND, the print is bigger!

Lots of info online, BIG Shout-Out ta algore for inventing the Internet!

Been a minute, but https://ecuip.com/solar-interconnection-guide/ dug out of my email, sent to myself, hope it works, for instance.

'Puters NOT my thing.

may as well get Yoself an ElectriCalc Pro | Calculated Industries while Yore @ it?

👁️'m Not too good wiff da maff, either

P.S. NOT 'sure' IF the "interconnection-guide" is going to show as a blue clickable hyper-link thingy or not. Copy/Paste or entered manually from 'here' before submitting both worked.
 
My Apologies. Writing, clearly, (might be sum kinda pun?) NOT in my Wheelhouse. Either.

YOU Will Really get Great Info/Exposure from the interconnection guide link! A Few others out there that are as good or better. No Time to look for You, Sure You can find 'em.

Brief Excerpt from the link:

"With so many service equipment configurations and local rules, interconnecting your solar PV system to the existing electrical system can be quite confusing. An improper connection can potentially spell disaster as equipment can be overloaded – don’t count on inspectors catching the mistake!"

"This post is to help clear things up so you know what is permitted by code and you can choose the best option depending on your particular situation. Unfortunately being up to code is sometimes not enough as the local jurisdiction and/or utility will have the final say so it’s up to you to make sure it’s allowed."

Jump to Relevant Section:​

Much more in the link. Plenty out there. Generic search for "Solar Interconnection Guide" will return MANY results.

Art.690 is Solar Photovoltaic (PV) Systems

(again for reference; 2020 NEC Handbook) FULL Code Word 4 Word (Verbatim?) Plus oodles of 'commentary', and be still my ❤️???

Great Pictures! (👁️'ma native WVian, if that helps explain my appreciation for Pics)

690.10 refers You to 710.15

Part VII. Connection to Other Sources

690.59 Refers You to "Parts I & 2 of Article 705 & 712...

You wil eventually come to the realization of why SO MANY 40A 'Back-Fed' breakers are out there.

Maybe Bonus Info: *IF "Interactive" NO Back-Fed "Hold-Down Device" Required.

But Don't take my word for anything. Research it until it drives Ya crazy. Too.

On a positive note?

I musta inadvertently turned off my email alerts for replies, Can NOT even remember how/when i did that, or how i turned them back on. However, it musta worked! Your email pointing out my poor communication skills is much appreciated.

Thank You.

GREAT place to learn, YUUGE Knowledge base of very supportive & smart people. Read here for years, but always worried i would embarrass myself asking for help/explanation/Was i reading something "correctly"?

250.24 (A) (4) springs to mind.

More free time coming up. Should be able to provide some good cover for the timid! 😳

Good Luck!
 
Ponchik said:
@darkenergy

I am sorry, I have no idea what you said.
Click to expand...
Me, either, but if "solar ready" means having a PV interconnection point on the supply (line) side of the service OCPD, then none of the business about bus ratings and backfed breakers, etc. is relevant. The limit on the size of a line side interconnected PV system is "the size of the service", which is not well defined in earlier versions of the NEC but in later versions it refers to the ampacity of the service conductors, which is valid as long as maximizing a PV system to that limit would not allow the utility transformer to be overloaded.
 
Ponchik said:
That is exactly what it means, based on
SQUARE-D
Click to expand...
Square D to my knowledge lately has been doing the other thing: 225A busbar on a 200A meter main. Looking at one on the shelf right now. Not saying they don't have other 'solar ready' products that are different.
ggunn said:
Me, either, but if "solar ready" means having a PV interconnection point on the supply (line) side of the service OCPD,
Click to expand...
It doesn't. It's not that specific.
 
jaggedben said:
ggunn said: Me, either, but if "solar ready" means having a PV interconnection point on the supply (line) side of the service OCPD,..
Click to expand...

jaggedben said:
It doesn't. It's not that specific.
Click to expand...
You're right. I looked at a few "solar ready" panels; The Siemens and Eaton panels I found have oversized busbars with dedicated PV breakers at the opposite end from the MCB, while the Square D one I found has a line side attachment point.
 
ggunn said:
You're right. I looked at a few "solar ready" panels; The Siemens and Eaton panels I found have oversized busbars with dedicated PV breakers at the opposite end from the MCB, while the Square D one I found has a line side attachment point.
Click to expand...
Whereas the Siemens and Square-D I'm most familiar with are the opposite. And there you go.
 
I'll add another wrinkle:
For one code cycle a few years ago, there was no allowance to put a solar breaker at either end of a center-fed residential panel. So the manufacturers redesigned their center fed meter mains to have the main breaker at one end. They also put a label on the deadfront at the opposite end that said something to the effect of 'In California this spot is reserved for the PV breaker'. (Because at the time (still?) California was the only state that required new housing to be solar ready.) There were no other differences in the ratings or configurations of the meter/mains. So that's in the past now, after more code changes, but for a while that was one meaning of 'solar ready.'
 
Status
Not open for further replies.
Top