Line side disco

[jaggedben]

Not to relight the fuse but we cannot resolve it in here as long as AHJ's don't agree. The only resolution is to do it like the AHJ wants.

Um... I think that's pretty much what I said! :?:lol:

 

[PWDickerson]

We are fortunate in WA in that the WA state chief electrical inspector came out with a clear ruling regarding supply side connections and published it in their monthly newsletter. Here is some of the text from the article.

The sum of the ratings of all overcurrent devices of powerproduction sources connected to a service cannot exceed therating of the service. The disconnecting means for theinterconnected power production source should be treated asan additional service in accordance with 230.2(A)(5). It doesnot count as one of the (up to six) disconnects of the mainbuilding service as allowed by 230.71, neither is it required tobe grouped with the main service disconnect(s). The wiringmethods, grounding, and bonding must be in accordance withArticles 230 and 250 as an additional service.
Overcurrent protection for power production sourceconductors connected in this manner must be located within10 feet of the point where the conductors connect to theservice in accordance with 705.31.


In installations where a supply side connection is made by
connecting the power production source overcurrent device to
a main lug service panelboard or switchboard, the sum of the
ratings of all interconnected power source overcurrent devices
must not be greater than the rating of the service equipment
or service conductors. The power production source
overcurrent device does not count as one of the main service disconnects.




Here is a link to the full article. http://www.lni.wa.gov/TradesLicensing/Electrical/files/currents/Elc1410.pdf

 

[PVfarmer]

Quite simply, 705.31 states that overcurrent protection must be located within 10 feet of the PV System disconnecting means.

I'm not sure about that, it says 10 feet from the "point of connection", meaning a junction box, splice point, etc. (Or a dual meter box as of 2017 in RI)
In this diagram, the "Service Main Disco 2 of 2" has to be 10 feet from the j-box.
https://www9.nationalgridus.com/non_html/DG_sample_1line_B.pdf

705.31 Location of Overcurrent Protection. Overcurrent
protection for electric power production source conductors,
connected to the supply side of the service disconnecting
means in accordance with 705.12(A), shall be located
within 3m (lOft) of the point where the electric power
production source conductors are connected to the service.

Argue that it is not officially a service disconnect. Thus 230.71 and .72 don't apply. I don't agree with this argument

I think it *is* a service disco, and agree that 230.71 doesn't apply, and so does the Chief Inspector in Washington State.
"It does not count as one of the (up to six) disconnects of the mainbuilding service as allowed by 230.71"
http://www.lni.wa.gov/TradesLicensing/Electrical/files/currents/Elc1410.pdf

Not to relight the fuse but we cannot resolve it in here as long as AHJ's don't agree. The only resolution is to do it like the AHJ wants.

I think the fuse should stay lit. Opposing AHJs can't both be 100% correct, and I think the WA state AHJ is in fact 100%.
I can't think of any reason to *not* bond the PV disco inside itself and run GEC to GES.
Why would one instead bond PV neutral to ground in the MSP, when code says you shouldn't?

this looks like the answer to me...


Funny the way y'all will say I'm wrong, but don't dispute the WA AHJ who is saying the same thing I am.

We are fortunate in WA in that the WA state chief electrical inspector came out with a clear ruling regarding supply side connections and published it in their monthly newsletter. Here is some of the text from the article.

The sum of the ratings of all overcurrent devices of powerproduction sources connected to a service cannot exceed therating of the service. The disconnecting means for theinterconnected power production source should be treated asan additional service in accordance with 230.2(A)(5). It doesnot count as one of the (up to six) disconnects of the mainbuilding service as allowed by 230.71, neither is it required tobe grouped with the main service disconnect(s). The wiringmethods, grounding, and bonding must be in accordance withArticles 230 and 250 as an additional service.
Overcurrent protection for power production sourceconductors connected in this manner must be located within10 feet of the point where the conductors connect to theservice in accordance with 705.31.


In installations where a supply side connection is made by
connecting the power production source overcurrent device to
a main lug service panelboard or switchboard, the sum of the
ratings of all interconnected power source overcurrent devices
must not be greater than the rating of the service equipment
or service conductors. The power production source
overcurrent device does not count as one of the main service disconnects.

Here is a link to the full article. http://www.lni.wa.gov/TradesLicensing/Electrical/files/currents/Elc1410.pdf

Thank you!
Here's some more expert input.

To justify the addition of the PV disconnect as shown, you must first refer to Section 230.40 Exception No. 5, which reads, “One set of serviceentrance conductors connected to the supply side of the normal service disconnecting means shall be permitted to supply each or several systems covered by 230.82(5) or 230.82(6).” If you then refer to Section 230.82 in general and to Section 230.82(6) in particular, you can show that “solar photovoltaic systems” or “interconnected power production sources” are “permitted to be connected to the supply side of a service disconnecting means.”


Following this logic, Exception No. 5 to Section 230.40 allows for the installation of an additional set of serviceentrance conductors, shown in brown in Figure 2, on the supply side of the service equipment associated with the house loads. You now have one set of service-entrance conductors supplying five occupancies and one house loads panel. In addition, you have a second set of service entrance conductors supplying the PV system.


Note that from the Code perspective— see Section 230.71(A)—there are two sets of service-entrance conductors in Figure 2. This is a key distinction to make in your conversations with plan checkers and inspectors.
http://solarprofessional.com/articl...-of-disconnects/page/0/1?v=disable_pagination

 

[ggunn]

I think the fuse should stay lit. Opposing AHJs can't both be 100% correct...

Of course they can. There is frequently more than one way to do something that is code compliant.

 

[jaggedben]

I think it *is* a service disco, and agree that 230.71 doesn't apply, and so does the Chief Inspector in Washington State.
"It does not count as one of the (up to six) disconnects of the mainbuilding service as allowed by 230.71"
http://www.lni.wa.gov/TradesLicensing/Electrical/files/currents/Elc1410.pdf

What you think doesn't matter because you're not a Chief Inspector of a US state.

It's nice for installers in WA that they have clarity, but it can't be counted upon for anything outside WA. And if I were the Chief Inspector the statement would read differently. :lol:

 

[PVfarmer]

There is frequently more than one way to do something that is code compliant.

Where's the alternative to the below then?
What exactly are you calling it to make the bonding in the disco *not* required?

If it's one service, all enclosures are bonded-250.28(2).
If it is two services, all enclosures are bonded.-250.24(B).

Is there another option?

250.24 Grounding Service-Supplied Alternating-Current Systems.

(A) System Grounding Connections. A premises wiring
system supplied by a grounded ac service shall have a
grounding electrode conductor connected to the grounded
service conductor, at each service, in accordance with
250.24(A)(1) through (A)(5).

(B) Main Bonding Jumper. For a grounded system, an unspliced
main bonding jumper shall be used to connect the
equipment grounding conductor(s) and the service-disconnect
enclosure to the grounded conductor for
each service disconnect in accordance with 250.28.

Exception No.1: Where more than one service disconnecting
means is located in an assembly listed for use as service
equipment, an unspliced main bonding jumper shall
bond the grounded conductor(s) to the assembly enclosure.

250.28 Main Bonding Jumper and System Bonding
Jumper. For a grounded system, main bonding jumpers
and system bonding jumpers shall be installed as follows:

(2) Main Bonding Jumper for Service with More Than
One Enclosure. Where a service consists of more than a
single enclosure as permitted in 230.71 (A), the main bonding
jumper for each enclosure shall be sized in accordance
with 2S0.28(D)(l) based on the largest ungrounded service
conductor serving that enclosure.

(3) Separately Derived System with More Than One
Enclosure. Where a separately derived system supplies
more than a single enclosure, the system bonding jumper
for each enclosure shall be sized in accordance with
2S0.28(D)(1) based on the largest ungrounded feeder conductor
serving that enclosure, or a single system bonding
jumper shall be installed at the source and sized in accordance
with 250.28(D)(1) based on the equivalent size of the
largest supply conductor determined by the largest sum of

 

[ggunn]

Where's the alternative to the below then?
What exactly are you calling it to make the bonding in the disco *not* required?

I'm not going around that tree again for the umpteenth time. If you want to go to the mat with Austin Energy (and every other AHJ in Texas outside of CPS/San Antonio) and try to convince them that they are wrong in their interpretation of the NEC, go ahead and let me know how it turns out. If you prevail I will cheerfully revise the way I design supply side connected PV outside of San Antonio and publicly thank you for making my life simpler. Otherwise I will go on bonding N to G for CPS but leaving them unbonded for every other AHJ in Texas as long as there is no islolating transformer between the inverter and the service.

Passing inspection overrules your interpretation every time. The real world is what counts, not your theoretical musings.

 

[PVfarmer]

Passing inspection overrules your interpretation every time. The real world is what counts, not your theoretical musings.

Yes, the real world, which is why I'm asking how they (and therefore you) justify it.

Also, it's apparently the State Inspector of WA's "theoretical musing", and not in fact mine!

The OP is from CT, shouldn't you be telling him to do what (I think) Direct Energy or the local inspector say (which would have to be the same), not what you do in TX?

Great, you do it that way- what's the code interpretation that backs it up?

If somehow you made a supply side tap *in the* MSP ahead of main breaker, then I'd understand bonding both PV system and loads in said MSP/same enclosure.
With the separate supply side disco enclosure...I don't understand.

 

[ggunn]

Yes, the real world, which is why I'm asking how they (and therefore you) justify it.

Also, it's apparently the State Inspector of WA's "theoretical musing", and not in fact mine!

The OP is from CT, shouldn't you be telling him to do what (I think) Direct Energy or the local inspector say (which would have to be the same), not what you do in TX?

Great, you do it that way- what's the code interpretation that backs it up?

I don't justify it; I follow instructions from the AHJ, the same as everyone else who designs PV systems in the real world. I am agnostic on the subject; your interpretation (and mine as well, for that matter) of the pertinent code is irrelevant. My advice to all who work in the industry is to check with the AHJ before building a PV system that may fail inspection.

What you are doing is no more than armchair quarterbacking. As I have said many times before, it makes no difference in my world whether you agree with the AHJs I deal with or not.

 

[PVfarmer]

I don't justify it;

What you are doing is no more than armchair quarterbacking. it makes no difference in my world whether you agree with the AHJs I deal with or not.

It sounds more like you don't care. This isn't about you!

It also sounds like you are trying to make a personal argument out of this, I'm not sure why.

Let me remind you- we are talking about *someone else's" question about this, asking *for opinions*:

"I would likeopinions and code references as to whether or not a supply side fused disconnect is "required" to be located with the main service disconnect per "grouping of disconnects" in Art 230. Or could the supply side fused disco be outside (within 10 feet) of a main disco that is inside."

 

[ggunn]

It sounds more like you don't care. This isn't about you!

It also sounds like you are trying to make a personal argument out of this, I'm not sure why.

Let me remind you- we are talking about *someone else's" question about this, asking *for opinions*:

"I would likeopinions and code references as to whether or not a supply side fused disconnect is "required" to be located with the main service disconnect per "grouping of disconnects" in Art 230. Or could the supply side fused disco be outside (within 10 feet) of a main disco that is inside."

I am not making it an argument at all; you are correct - I really don't care. My only argument with you is that you seem to think that your interpretation of the code is the only correct one. It's not.

My answer to his question is the same - ask the AHJ. Some may allow the disco to be on the other side of a wall and others may not. Things like this are frequently not purely a code issue, and a preconstruction meeting with a rep of the AHJ can often save a big headache later.

 

[PVfarmer]

I really don't care.

you seem to think that your interpretation of the code

Things like this are frequently not purely a code issue, and a preconstruction meeting with a rep of the AHJ can often save a big headache later.

Why don't you care, and why bother posting if you don't? It does matter to the OP.
Giving the OP the code references he is looking for sounds polite to me.

It is *not* my interpretation- it's National Grid's and therefore my engineer's, the town inspector where I live has seen a total of one supply side connections before. (He's a lot cooler about 'my opinion' than you are!)

Nat Grid literally says "supply side connections must be installed following code"! :huh:
And of course it is *not* their job to explain code to people.

"I'm doing this without code references because I think it is right"?
Not sure how that tactic would work in reality.

whether or not a supply side fused disconnect is "required" to be located with the main service disconnect per "grouping of disconnects" in Art 230.
It is not. Period.

could the supply side fused disco be outside (within 10 feet) of a main disco that is inside.
It doesn't matter where the main load disco is, you can put some sort of fused PV disco outside or inside.
There can only be 10' of conductor run between that fused PV disco and the supply side tap location/j-box.

I don't get why someone would put one inside when some sort of outside switch is required, is simpler, and is definitely to code.

As in, where I am, you could have: (with an outdoor meter)
A- Non-fused "POCO PV disco" switch adjacent to outdoor meter --> fused disco inside -- > up to 10' to j-box inside, j-box is 'before' main loads breaker, also inside.
B- Fused switch outside up to 10' from outside j-box, SECs lead from j-box to main loads breaker, which is inside.

(Edit: For a visual aid, I'm saying this "Interior AC PV Disco" pictured here could be moved outside (it would still be 'Service Disco 2 of 2')- then the unfused "Exterior AC Utility Disco" is redundant and not needed.)
https://www9.nationalgridus.com/non_html/DG_sample_1line_B.pdf

Are there any POCOs that don't require some sort of switch outside?
Why do the bold part when B is simpler?

Nat Grid now requires a dual meter for residential feed-in-tariff systems, one for PV output, the other for loads.
You simply cannot skip the N-G bond in the PV disco with a dual meter- since they *are both services*...

 

[ggunn]

Why don't you care, and why bother posting if you don't? It does matter to the OP.
Giving the OP the code references he is looking for sounds polite to me.

I'm not going around that tree again with you. I believe I have made my thoughts on the matter very clear, but here they are again:

Whether the AC disco on a line side connected PV system is a service entrance or not (and all that entails) is a matter of interpretation of the NEC, and interpretations by AHJ's can and often do disagree; two of the biggest AHJ's in Texas have opposing views. In order to avoid risking the failure of your inspection and having to do the commensurate rework, check with the AHJ governing your installation before building the system and follow their directives.

 

[PVfarmer]

check with the AHJ governing your installation

Great, so maybe the OP's AHJ is like you and doesn't care either way.

But the OP still needs the opinions *with* code references to make a case either way.
So what are those of the AHJ in TX that wants it done "your way"?

I think-
Supply side PV *is* a service.
The six handle rule does *not* apply.
Within 10 feet may *not* apply.

Question- if the supply side PV isn't a service, what *do* you call it?


I would like opinions and code references as to whether or not a supply side fused disconnect is "required" to be located with the main service disconnect per "grouping of disconnects" in Art 230.
or
could the supply side fused disco be outside (within 10 feet) of a main disco that is inside

Supply Side Connection – 690.64(A)
• Allowable per 230.46 and 230.82(6)
• 60A minimum PV service entrance conductors
per 230.42(B)
• 60A minimum PV service disconnect per
230.79(D)
• Must be protected per 230.50(A) & (B)
• Remember clearance requirements per 110.26
• Article 230.90(A) says OCPD shall not exceed
the rating of the existing service entrance
conductors.
• Over Current Protective Device (OCPD) to
cover inverter output conductor per 690.8(B)1
• Protection against physical damage per 230.50
- remember these conductors will have no
OCP all the way back to the primary side of
the utility transformer
• Take care to meet 110.9 requirements
• Article 230.70(A)1 – service disconnecting
means shall be installed at a readily accessible
location either outside of a building or
structure or inside nearest the point of
entrance of the service conductors.
• Conductors and conduits should be as short as
possible
• Article 230 applies - Adding new service
equipment in parallel with existing equipment
• Article 240 tap rules do not apply to inverter
connections since the tap rules were
developed only for circuits with one source.
“10-foot tap rule” does not apply
• 250.24 rules apply to this new service
equipment
A) each service shall have a GEC connected to the
grounded service conductor (Neutral)
• Must have N-G bond and originate new GEC.
• GEC to be irreversibly spliced to existing AC
GEC, or new GE connected to existing GE
https://www.nyserda.ny.gov/-/media/...nnecting PV Systems with the Utility Grid.pdf

 

[ggunn]

Great, so maybe the OP's AHJ is like you and doesn't care either way.

That's highly unlikely. Both Austin Energy and CPS Energy (San Antonio) feel very strongly about it; they just disagree. By the way, in both jurisdictions their Design Criteria and Interconnect Guidelines are documents supported and enforced by city ordinance. Even if I wanted to get either of the governing AHJ's to change their position (I don't) I would have to go to their respective City Councils and get the law changed.

I care very much about building safe systems and passing inspections. What I do not care about is your opinion that the way you see it is the only valid interpretation of the code. I'll ask you again: how involved in the solar industry are you? Is this a real world issue for you or are you just trolling the internet?

 

[PVfarmer]

Both Austin Energy and CPS Energy (San Antonio) feel very strongly about it;

Well then they must have reasons to feel that way!
What are they?

" the way you see it is the only valid interpretation of the code."

No. More like you don't want to explain the alternative way of seeing it (like the OP asked us to do), so again, what's the point of your comments?

 

[ggunn]

Well then they must have reasons to feel that way!
What are they?

" the way you see it is the only valid interpretation of the code."

No. More like you don't want to explain the alternative way of seeing it (like the OP asked us to do), so again, what's the point of your comments?

The way you see it and the way I see it are irrelevant. The way the AHJ sees it is what counts. I do not know how to make that any clearer.

I'll try once more and then I am done.

Say I have a PV system to install at a residence where the MDP has a 200A bus with a 200A main breaker. 125% of my inverter's output max current is less than 40A. I could land the inverter output on a backfed breaker at the opposite end of the bus from the main breaker, or I could land on a tap between the MDP and the meter. The NEC does not dictate which way I do it; both ways are compliant as long as I follow the rules for that method of interconnection. The AHJ may, on the other hand, have a preference, so it behooves me to look through their interconnection guidelines to see if they do, and if they do, to design and build the system according to their preference. It makes no difference which I think is the best way; they have the authority to fail me on my inspection if I build it not according to their specifications.

This is the same situation. I have pored through the NEC ad nauseum concerning this issue and I can see how it can be (and IS) interpreted a couple of different ways. Furthermore, I cannot see any safety concerns with either interpretation. If I did I would be compelled by the rules governing my PE license to challenge the unsafe interpretation.

So there it is. I really do not care that you see it differently than every AHJ in Texas other than CPS in San Antonio, and I am not interested in arguing with you to prove you wrong. Your interpretation isn't wrong, it's one of two interpretations that are right. My advice is, and remains, to check with the AHJ before proceeding with a line side interconnection so that you do not run afoul of their way of connecting.

Since you haven't answered my oft repeated question regarding your involvement (or not) in actually designing and building PV systems, I can only assume that you are simply arguing for the sake of arguing, and I grow weary of it. I will respond to questions of substance but I am done with this line of "debate".

 

[jaggedben]

Well then they must have reasons to feel that way!
What are they?

The reasons are irrelevant if they're committed to a position and refuse to change. I was going to say that I have never changed an AHJs mind on an issue that they had already formed a strong opinion on. Then I remembered one job, where through shear persistence, luck, and necessity, I finally convinced them to let me invoke a code section that clearly permitted what I wanted to do. It took 6 months to get a 2kW system approved, and the issue shouldn't even have been open to reasonable disagreement, unlike what this thread was about.

Since then I've tried harder to just find out what the AHJ wants.