Location of A/C Disconnects in Solar PV residential Systems.

[FESApprentice2496]

The easiest way to explain my setup is the picture attached. The inspector is stating I'm in violation of 230.72. But looking into it more and listening to this video, https://www.youtube.com/watch?v=7vD0r_bVjuo

I don't think that disconnect needs to be down in the basement. Cause from what Mike said it's not a "service" disconnect

 

[jaggedben]

You may be able to satisfy your inspector by having some really nice placards made up that comply with 705.10. But if he is convinced that it doesn't matter because the PV disconnect is a service disconnect, then I can only wish you luck.

Yeah, Mike Holt said that it isn't a service disconnect, but just saying it doesn't make him right. The code is pretty vague. We've had some knock-down drag-out arguments on this forum about it, with no real conclusion.

 

[electrofelon]

Yeah, Mike Holt said that it isn't a service disconnect, but just saying it doesn't make him right. The code is pretty vague. We've had some knock-down drag-out arguments on this forum about it, with no real conclusion.

But if you look at 230.40 ex #5, it clearly says.......... just kidding.

 

[FESApprentice2496]

do you have any thread links that I could read? seems like you have talked about it before in threads. I tried to download the NEC history spreadsheet but can't get a working link to see when 230.72 wasn't put in there and the wording "grouped" cause I have seen many times services with 200 A SEU cable going down to a double meter base, then coming out of the bottom with SEU 100 A cable one going to the first floor the other going to the second. same service two different disconnects, not in the same spot... maybe most don't enforce this rule.

 

[jaggedben]

This is the one that comes to my mind...

http://forums.mikeholt.com/showthread.php?t=169210&highlight=Pv+service+disconnect

That issue really comes down to whether the PV disconnect is officially a service disconnecting means, and there's several code sections each that can be read to imply that it is or is not.

But your question is about grouping, not bonding...

Now that I think about it a little more, I believe that 230.71 refers to grouping for each 'set of service entrance conductors'. So if you installed a new set, you should consider the argument that you are permitted a whole new group. I don't have the book handy right now to quote it though.

 

[mwm1752]

Interesting comments -- but if you reason that a interactive system will not allow AC past the inverter once the grid is disconnected then the service disconnects in the basement does actually serve as a disiconnecting means for the PV putput circuits -- similar to a shunt trip for the utility MDP "if" it was installed by the exterior PV disconnect. Signage should suit the issue IMHO

 

[PVfarmer]

In my parts, there has to be disconnect on the outside of the garage for the POCO to shut the PV system down easily. ( A / Exterior)
It doesn't have to be fused. Perhaps it can be, but doesn't have to be.
But if C is not in the same place as the meter, B has to be with C.

So by your diagram, the inspector wants the "outside garage" disconnect (and fuses) moved to the basement...I'd still be required to have the "outside garage" switch, non-fused after putting the fused version in the basement.

I also have a question- if the PV is connected LOAD side, can A be "exterior", and then be connected to a "B" in the same panel as "C" and...still count as "B"? As long as labeled as such?

A B C here:
http://www.nationalgridus.com/non_html/dg_sample_1line_b.pdf

A Exterior AC Utility Disconnect Switch (non-fused)
###A, ###VAC
(Located Adjacent to Utility Meter)

B Interior AC PV Disconnect Switch (fuse OR breaker)
###A, ###VAC
(Service Main Disconnect 2 of 2)

C Existing Main Breaker (in basement)
(Service Main Disconnect 1 of 2)

 

[iwire]

In my parts, there has to be disconnect on the outside of the garage for the POCO to shut the PV system down easily.

Thats rough, you have to build a garage to install a PV system.

 

[jaggedben]

In my parts, there has to be disconnect on the outside of the garage for the POCO to shut the PV system down easily. ...

You should really stop interjecting in every thread with the POCO requirements in your area, because every utility may have different requirements, and thus what's required in your area is irrelevant to other areas.

The OP's question was evidently about the AHJ interpretation of NEC requirements.

 

[PVfarmer]

You should really stop interjecting in every thread with the POCO requirements in your area
The OP's question was evidently about the AHJ interpretation of NEC requirements.

Thats rough, you have to build a garage to install a PV system.

I think you guys should stop interjecting this attitude that I'm a fool! This isn't a joke.

Two questions- why are there ATS switches in the diagram? And more importantly, why isn't there a PV disco in the basement?
Y'all are saying the code is confusing, and then giving me attitude for saying what I think the code might say.

Guess what- sometimes common sense helps. The OP's AHJ is wrong to say "move the outdoor disconnect to the basement".
Why? Well, what's missing then? The outdoor switch for the utility (and fire dept)! The fire dept would probably prefer it if the main house panels were also outdoors, but that certainly isn't required.

My personal opinion, based on nothing more than common sense, would be to move the fused switch *inside* the garage to the basement, and leave the switch outside the garage where it is, no fuse in outdoor switch.

Then you have a switch in the basement for any apprentice electrician who comes by to work on the house.
Trusting the homeowner to say "hey, there's 10,000w of PV out back", or trusting a random electrician (who may have never seen a PV system before) to read and obey some sign in the basement saying "go out to the garage to turn off the PV"...sounds very dangerous to me.

If you really want to get into code, 230.72(B) says "one additional remote" disconnect is allowed- that would be the one on the garage (or on a post. Whatever).
So the rest (including PV disconnect, which the outdoor switch is NOT) have to be grouped.
Makes sense to me, and is also what is described in the POCO example link I posted.

If this system in the diagram made a load side connection to the panel in basement, the panel breaker would be the PV disco- but you still want a PV disco next to the panel when the PV is line side.

 

[iwire]

I think you guys should stop interjecting this attitude that I'm a fool! This isn't a joke.

Not a fool, just woefully unqualified to be giving out advice on this forum. You have proven that point multiple times.

The OP's AHJ is wrong to say "move the outdoor disconnect to the basement".
Why? Well, what's missing then? The outdoor switch for the utility (and fire dept)! The fire dept would probably prefer it if the main house panels were also outdoors, but that certainly isn't required.

This is exactly the type of thing jaggedben was pointing out, you are making general statements about things that change in each area.

 

[PVfarmer]

I said
The outdoor switch for the utility

This is exactly the type of thing jaggedben was pointing out, you are making general statements about things that change in each area.

Seeing as he most probably put the "outside garage" switch in his drawing in that spot for a reason, I went ahead and assumed it was for his POCO. What else would it be for?

Do you have any thoughts about this?

If you really want to get into code, 230.72(B) says "one additional remote" disconnect is allowed- that would be the one on the garage (or on a post. Whatever).

The way I read it is that the outside garage switch is for the POCO, and the OP's inspector wants the "inside garage" switch in the basement, to satisfy the requirement of there being a PV disconnect at the main panel.

How would you put one of these signs in the basement...without a switch to put it on?

 

[PVfarmer]

The drawing doesn't say how far apart the components are, so...?

Also- FESApprentice2496- the inverter output says 41.7A, and 41.7 *1.25 is 52.125. Just wondering why you have 50A fuses there in the 60A boxes?

 

[jaggedben]

Seeing as he most probably put the "outside garage" switch in his drawing in that spot for a reason, I went ahead and assumed it was for his POCO. What else would it be for?

Do you have any thoughts about this?

I have too many thoughts to try to guess which ones might be correct and offer advice on that basis.

Articles 705 and 690 have various disconnecting requirements in addition to 230 which may or may not be enforced and interpreted as required by the AHJ. For example, many jurisdictions require a disconnect grouped with the inverter (per 690.14 or 15, so your idea of moving the inside one to the basement wouldn't work in that case.

The OP asked about requirements for grouping service disconnects, so it makes sense to remain focused on his question.

How would you put one of these signs in the basement...without a switch to put it on?

You would have another placard custom made that said something such as "Warning: Photovoltaic System Connected. The Photovoltaic Disconnecting means is located on the outside of the garage." I've done this sort of thing several times when AHJs asked.

 

[jaggedben]

My personal opinion, based on nothing more than common sense, would be to move the fused switch *inside* the garage to the basement, and leave the switch outside the garage where it is, no fuse in outdoor switch.

In the case of a supply side tap, the first disconnect coming from the utility must be fused. There's no reason that the one inside the garage had to be fused in the first place, but it's required to be there if the AHJ interprets the grouping requirement to apply and enforces it. So moving the disco inside the garage is bad advice if you aren't the one who had the conversation with the inspector.

 

[PVfarmer]

In the case of a supply side tap, the first disconnect coming from the utility must be fused. There's no reason that the one inside the garage had to be fused in the first place, but it's required to be there if the AHJ interprets the grouping requirement to apply and enforces it. So moving the disco inside the garage is bad advice if you aren't the one who had the conversation with the inspector.

I've done this sort of thing several times when AHJs asked.

In the case of a supply side tap, the first disconnect coming from the utility must be fused. There's no reason that the one inside the garage had to be fused in the first place, but it's required to be there if the AHJ interprets the grouping requirement to apply and enforces it. So moving the disco inside the garage is bad advice if you aren't the one who had the conversation with the inspector.

inside the garage... required to be there if the AHJ interprets the grouping requirement...

I'd be really interested to know how exactly it gets interpreted that way- if y'all are saying that the AHJs interpret Sec 230 to mean a PV system is a "service", any PV OCPD would then have to be 10 feet from a supply side tap or else load side- that says nothing about "OCPD at PV inverters".
There seems to be "source confusion", as in in "PV OCPD must be close to source" means source=grid, and NOT source=PV inverter(s), but some will go with the latter?

I don't think I said "maybe move the disco INSIDE the garage"- I thought I said "in my area I'd move the one in the garage to the basement".
I don't see how the switch inside garage (for PV overcurrent protection) is the "first disconnect from supply side tap", as there's the outside switch...so I thought the AHJ was interpreting the grouping by saying "the PV disco must be grouped in basement" (which is why he was referring to the outdoor switch , or closest to supply line).

Not sure how any AHJ in any case could say "you need PV overcurrent protection AT the inverters AND PV overcurrent grouped with your main switch AND they both have to be within 10 feet of the junction box for line side..."?

Hey! Let's ask the person with the question instead of arguing!

FES- What are the purposes of the two switches shown?
Is the outside garage switch for your POCO (exterior utility disco?), or is that the inverter OCPD?
In my area. if it is for POCO, it isn't a "service disconnect".
So with a line side tap, you have 2 service discos (as in the pdf I posted earlier) and if it's load side PV connection (example below), you only have one Service D, (and the PV breaker feeding the MDP is your PV OCPD while the main breaker is the 1 service disco.)

Load side/line side examples:
http://www.nationalgridus.com/non_html/dg_sample_1line_a.pdf

http://www.nationalgridus.com/non_html/dg_sample_1line_b.pdf

 

[mwm1752]

705.1 Scope Your PV system qualifies
This article covers installation of one or more electric power production sources operating in parallel with a primary source(s) of electricity.
230.72 Grouping of Disconnects Comes into play with every service
(A) General. The two to six disconnects as permitted in 230.71 shall be grouped. Each disconnect shall be marked to indicate the load served. 230.71 Maximum Number of Disconnects How a PV system can be interpreted as a service
(A) General. The service disconnecting means for each service permitted by 230.2, or for each set of service-entrance conductors permitted by 230.40, Exception No. 1, 3, 4, or 5, shall consist of not more than six switches or sets of circuit breakers, or a combination of not more than six switches and sets of circuit breakers, mounted in a single enclosure, in a group of separate enclosures, or in or on a switchboard or in switchgear. There shall be not more than six sets of disconnects per service grouped in any one location.
For the purpose of this section, disconnecting means installed as part of listed equipment and used solely for the following shall not be considered a service disconnecting means:
(1) Power monitoring equipment
(2) Surge-protective device(s)
(3) Control circuit of the ground-fault protection system
(4) Power-operable service disconnecting means
230.2 Number of Services See (A) (5)
A building or other structure served shall be supplied by only one service unless permitted in 230.2(A) through (D). For the purpose of 230.40, Exception No. 2 only, underground sets of conductors, 1/0 AWG and larger, running to the same location and connected together at their supply end but not connected together at their load end shall be considered to be supplying one service.
(A) Special Conditions. Additional services shall be permitted to supply the following:
(1) Fire pumps
(2) Emergency systems
(3) Legally required standby systems
(4) Optional standby systems
(5) Parallel power production systems Article 705
(E) Identification. Solution for labeling & type of plaque
Where a building or structure is supplied by more than one service, or any combination of branch circuits, feeders, and services, a permanent plaque or directory shall be installed at each service disconnect location denoting all other services, feeders, and branch circuits supplying that building or structure and the area served by each. See 225.37


I would interprete you situation as the AHJ does not consider the PV as an additional service, but as part of a single service in which 230.72(A) applies.

230.31 Size and Rating For overhead services also
(A) General. Underground service conductors shall have sufficient ampacity to carry the current for the load as calculated in accordance with Article 220 and shall have adequate mechanical strength.

Does this apply to your PV system that is a line side tap? There are certain ways of dealing with this.
I can go on with many articles to reason both sides but some of the purpose is for the OP to research all of the angles for better understanding. You shouldn't get emotional with this tough crowd as it does no good. When I get blasted I find out why for better understanding as anyone who says they know it all will soon be proven wrong.

 

[jaggedben]

inside the garage... required to be there if the AHJ interprets the grouping requirement...

I'd be really interested to know how exactly it gets interpreted that way- if y'all are saying that the AHJs interpret Sec 230 to mean ...

You know, if you'd read what I said, I mentioned sections 690.14 and 690.15. It's 690.15 in the 2011 code and I believe it's part of 690.14 in the 2014 code; I know they reorganized the sections but I don't have the 2014 with me right now.

Not sure how any AHJ in any case could say "you need PV overcurrent protection AT the inverters AND PV overcurrent grouped with your main switch AND they both have to be within 10 feet of the junction box for line side..."?

The sections in 690 require a grouped disconnect with the inverter, but not overcurrent protection. And AHJs can say just about anything they darn please. It's a problem sometimes. With that said, I'm not sure how your extrapolated that both have to be within 10ft of the junction box. Only the one closest to it does.

Hey! Let's ask the person with the question instead of arguing!

That was pretty much my point. Let's ask the person with the question to clarify what their inspector said before offering advice that might not be accordance. Let's also focus on his question instead of bringing up other stuff that's probably irrelevant. The disco at the inverter seems to be irrelevant to the issue our OP is having with his AHJ, judging from what the OP told us.

FES- What are the purposes of the two switches shown?

The one near the tap is overcurrent protection and a service disconnecting means. The one at the inverter is to provide an easy way to disconnect the inverter if you're working on it. It's typical for large pieces of equipment to have a required nearby disconnect (air conditioners, for example) if the circuit originates somewhere remote.

 

[PVfarmer]

You know, if you'd read what I said,

I did, my reply was removed, so I give up, just trying to help but I'm wasting my time.
Seemed like a good reply to me.
So...good luck, guys! :huh:
Catch y'all on the flip side of the switch?

Apologies to whomever was upset by my comments.
And Happy New Year/ 2017 code to all!

 

[FESApprentice2496]

PVFarmer I appreciate your thoughts and advice but pretty disconcerting that you are giving out advice but asking why I have the ATS's Drawn. I thought it was a given, its in the drawing because its there at the house and those are your service disconnects.

But anyway I've been thinking about this over the holidays, and I agree with the one poster who was on the road. 230.71 article states Service entrance conductors or "services". I have three seperate sets of service conductors, and each set should be allowed its own place, IMO. Haven't gotten in contact with the inspector yet.

To me it seems like 230.71 and 230.72 are about limiting one location/enclosure to 6 disconnects. Not meaning they all have to be in the same location.