690 or 705 sections that need changes for the 2020 NEC cycle?
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PVfarmer
Senior Member
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- Newport County, Rhode Island, USA
When it says power production sources that doesn't include the utility. See 705.2 definitions where it says 'other than a utility.'
I hear you, but there is no definition there for power production sources, or power production source.
There's Power Production Equipment, defined as one source.
But it says we're allowed to connect a single PP source (A), and also to add up the OCPDs connected to PP sources (B, plural).
Also, the "rating of the service"- that sounds as if it could mean the "200A service" from the POCO, isn't it really supposed to mean the service *breaker*, not conductors or transformer?
705.2 Definitions.
Power Production Equipment. The generating source,
and all distribution equipment associated with it, that generates
electricity from a source other than a utility supplied
service.
Informational Note: Examples of power production equipment
include such items as generators. solar photovoltaic
systems. and fuel cell systems.
705.12
(A) Supply Side. An electric (A)power production source shall
be permitted to be connected to the supply side of the service
disconnecting means as permitted in 230.82(6). The sum of
the ratings of all overcurrent devices connected to (B)power production
sources shall not exceed the rating of the service.
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Maybe...
705.12
(A) Supply Side. Power production equipment shall
be permitted to be connected to the supply side of the service
disconnecting means as permitted in 230.82(6). The rating of
the overcurrent device protecting the power production equipment
shall not exceed the rating of the service disconnecting means.
I hear you, but there is no definition there for power production sources, or power production source.
There's Power Production Equipment, defined as one source.
But it says we're allowed to connect a single PP source (A), and also to add up the OCPDs connected to PP sources (B, plural).
Also, the "rating of the service"- that sounds as if it could mean the "200A service" from the POCO, isn't it really supposed to mean the service *breaker*, not conductors or transformer?
705.2 Definitions.
Power Production Equipment. The generating source,
and all distribution equipment associated with it, that generates
electricity from a source other than a utility supplied
service.
Informational Note: Examples of power production equipment
include such items as generators. solar photovoltaic
systems. and fuel cell systems.
705.12
(A) Supply Side. An electric (A)power production source shall
be permitted to be connected to the supply side of the service
disconnecting means as permitted in 230.82(6). The sum of
the ratings of all overcurrent devices connected to (B)power production
sources shall not exceed the rating of the service.
|
|
|
Maybe...
705.12
(A) Supply Side. Power production equipment shall
be permitted to be connected to the supply side of the service
disconnecting means as permitted in 230.82(6). The rating of
the overcurrent device protecting the power production equipment
shall not exceed the rating of the service disconnecting means.
The utility does not produce power on site. The mentioned sources do produce power on site... and also fall under the purview of the NEC.
PVfarmer
Senior Member
- Location
- Newport County, Rhode Island, USA
I realize that my own personal opinion is irrelevant- that's the whole point!
See example below of actual working AHJ asking for clarification.
Is a PV system defined as multiple sources, or just a single source?
Well, both:
X: a generating source
Y: a power production source
Z: power production sources
But more importantly- what is the definition of the "rating of the service"?
Like I said, conductors? Breaker?
It seems pretty straightforward that 705.12 should at least say the PV OCPD:
"shall not exceed the rating of the service disconnecting means."
I'm not sure why you'd use "the sum of the ratings of all overcurrent devices" to calculate PV when there's a single PV switch equal (or nearly = ) to that sum.
Example :4 x 30A PV breakers (sum=120A) into an MLO PV combiner panel. Since there are no 120A fuses, you use a 125A fused PV switch.
Therefore, you have to have a minimum 125A service breaker.
There could be a "200A POCO service" with 150A service conductors and a 100A service disconnecting means.
I have a 100A breaker in my own house, yet my service entrance conductors are at least 1/0.
I don't have one of these fancy business cards on hand...
---
I doubt that anyone would recommend that I take a caliper to them inside the box.
How do experienced inspectors deal with this?
I also have a service cable guide for 60, 100, 150, and 200 amp cables printed on the backside of my business cards so if I have doubts, I can hold a card up to the width of the cable for comparison. I have seen copper service cables which run thinner than aluminum service cables so they can throw off visual estimations.
This can throw a wrench in the works but sometimes a house can have a 200 amp service cable entering the meter box and service panel but only a 100 amp main disconnect inside the service panel. In this case, the house really only has 100 amp service.
http://www.inspectionnews.net/home_...ion/32906-electrical-service-rating-help.html
705.2 Definitions.
Power Production Equipment. The generating source, (x)
(A) Supply Side. An electric (A)power production source (Y) shall
be permitted to be connected to the supply side of the service
disconnecting means as permitted in 230.82(6). The sum of
the ratings of all overcurrent devices connected to (Z) power production
sources
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
You're not going to find any of this explained clearly in the code. Here is my understanding, for what it's worth.
A single PV system is a power production source. There can be multiple systems on one premise. A PV system is defined in the code: you may not find that definition super helpful, as it leaves quite a bit open to interpretation when it comes to details. My personal view is that each separate disconnecting means/overcurrent device that is connected to inverters constitutes a separate system with respect to code requirements. At the very least, I would strongly argue that the aggregated output of several such connections, not mixed with distribution for loads that are unrelated to the system, constitutes a system. Again, a PV system is a source. There can be other types of sources, see articles 692 and 694.
The rating of a service is not defined clearly either, but common sense says it is the lowest rating (weakest link) of any component or conductor from the service point to the service disconnecting means (inclusive).
That is exactly how one does it, if the original markings are missing or unreadable. Hopefully with proper PPE or with the power shut off. A plastic caliper might make you feel safer. I would perhaps concur that no one recommend that you in particular do it, since my understanding is that working in energized enclosures is part of your training or experience.
Of course experienced inspectors can also just look at the wire and often tell what the size is.
A single PV system is a power production source. There can be multiple systems on one premise. A PV system is defined in the code: you may not find that definition super helpful, as it leaves quite a bit open to interpretation when it comes to details. My personal view is that each separate disconnecting means/overcurrent device that is connected to inverters constitutes a separate system with respect to code requirements. At the very least, I would strongly argue that the aggregated output of several such connections, not mixed with distribution for loads that are unrelated to the system, constitutes a system. Again, a PV system is a source. There can be other types of sources, see articles 692 and 694.
The rating of a service is not defined clearly either, but common sense says it is the lowest rating (weakest link) of any component or conductor from the service point to the service disconnecting means (inclusive).
That is exactly how one does it, if the original markings are missing or unreadable. Hopefully with proper PPE or with the power shut off. A plastic caliper might make you feel safer. I would perhaps concur that no one recommend that you in particular do it, since my understanding is that working in energized enclosures is part of your training or experience.
Of course experienced inspectors can also just look at the wire and often tell what the size is.
PVfarmer
Senior Member
- Location
- Newport County, Rhode Island, USA
1- You're saying that 1 system = 1 source, and then saying that several aggregated systems (or sources?) also = 1 system.
Isn't that because there's a single switch for the aggregated sources?
Multiple sources to me are inverters.
They aggregate into a system.
Then talking about the PV system being connected to other systems, the disconnect switch for the PV system is also the source of the PV system. Switch off/ PV system not connected.
(The entire aggregation is going through one point, the disco switch).
2- Yes, common sense = lowest rating.
Common sense is *not* important components not being labeled.
3- There are exactly about 12 ways inspectors do it (or not) in that one forum thread.
I also have a service cable guide for 60, 100, 150, and 200 amp cables printed on the backside of my business cards
That's a good tip. If I can find a store that carries these cables I can take my calipers and develop a figure of merit.
Not at all accurate. Different cables and insulations types will wreak havoc on this philosophy.
If you can't get the tabs, get some short samples of cable and compare the conductor(s)
Those plastic gauges would be nice. Barring that, either read the lettering on the cable or familiarize yourself with typical service cables and go by eye.
Go to an electrical supply house and get 6"or 8" pieces of all of their service cables.
In my area, I am just barely permitted, by the provincial Safety Authority, to remove the cover. I am not permitted to "perform work" inside the panel. To me, that bars us from poking around in there.
If you had 2/0 cu sec but a main breaker rated at 150 amps, would the service be rated at 200 amps? No. The service would be rated at 150 amps.
There would be a problem if it were the other way around. Lets say the sec is 1-cu, which is rated at 150 amps and the main breaker is rated at 200 amps. The service would still be rated at 150 amps, but there would be a safety issue because the main would allow more amperage to be drawn through the sec than it is rated for.
PVfarmer
Senior Member
- Location
- Newport County, Rhode Island, USA
Every single inverter has its own OCPD.
Every supply side PV system also has a single set of conductors which carry the aggregated PV output to grid and load.
Getting super-technical, the "source" for the aggregated PV output is the *busbar* in the PV combiner panel.
If there's a main breaker in the PV combiner panel, that's the first PV OCPD.
The fused switch could be called the 2nd or auxiliary.
Or the fused switch could be the first if you have a MLO combiner and call the "each separate" ones for each inverter "inverter OCPDs".
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
Something like that. It's somewhat open to interpretation I think. If you have two string inverters, each tied to it's own breaker, and one can be disconnected without affecting the other, then how is that not two PV systems? Either system by itself meets the Article 100 definition.
"Photovoltaic (PV) System. The total components and
sub-system that, in combination, convert solar energy
into electric energy suitable for connection to a
utilization load."
Either inverter and its modules meets the definition without needing the other inverter and its modules.
Or not. They don't aggregate into a 705 'source', in my opinion, unless they share some dedicated distribution equipment that allows the entire source to be shut off at once.
705 definition:
"Power Production Equipment. The generating source,
and all distribution equipment associated with it, that
generates electricity from a source other than a utility
supplied service."
To me this section is badly worded. I'd replace 'associated with' with 'dedicated to'. 'Associated with' could mean the panelboard where the source is connected with a breaker and that just doesn't make sense if there are normal loads in that panelboard and everything else about it is a normal panelboard used to distribute power and not produce it. Now if you have a panelboard whose sole purpose is to aggregate the power produced by other power production equipment, then it makes sense to consider that panelboard part of a source.
Say you have two inverters that are connected in two different subpanels on a property. Both subpanels have normal loads in them. It makes no sense whatsoever to regard both inverters are a single source for purposes of subpanel busbar calculations. However if on a different property you have two inverters that are aggregated in a dedicated subpanel before being connected elsewhere, it makes sense to call that subpanel part of the source.
I don't think your wording is helpful here. Yes, the source or system has a disconnecting means that isolates it from everything else, and that marks a line between the source and other stuff, but the source or system itself is a combination of multiple components, not the disconnecting means.
Microinverters don't.
You could have multiple 'PV systems' connected to one supply side connection, in my opinion. What would be a violation (of article 230.40, if there's no other valid exception) would be to add normal loads to the same supply side connection, unless that connection is already one of the six disconnects allowed by 230.71.
You can also have multiple supply side connections on one service. See the wording of 230.40 Exception 5.
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
What difference does it make?
PVfarmer
Senior Member
- Location
- Newport County, Rhode Island, USA
I still think this works:
705.12(A) Supply Side.
Power production equipment shall be permitted to be connected to the
supply side of the MAIN service disconnecting means as permitted in 230.82(6). The rating of
the overcurrent device or sum of OCDs protecting the power production equipment
shall not exceed the rating of the service disconnecting means or service conductors, whichever is lower.
8-
Exception No.5: One set of service-entrance 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). ... (5) = fire pumps, 230.82(6) = Solar photovoltaic systems
Wasn't it you that told me PV systems do *not* get supplied, so therefore aren't a service?
And what is "each or several"? How many exactly is several? :huh:
1- Either system by itself is not "the total components". And "connection" sounds singular.
2- If there is one set of PV conductors for the output of 4 inverters, there's going to be a breaker or fuses for them. That's *part of* the thing in green, and it can be the disconnect for 1 inverter or 12 inverters.
3- I'd say a Rapid Shutdown switch is dedicated to disconnecting the PV system/source.
4- I'd say the first bolded part is 2 systems, and the second is one. It's two sources both times.
5- It should say "All of the"
The total components and sub-system that, in combination
You said-
a combination of multiple components
Either system by itself
I really don't get what you are getting at.
one inverter ---> panel ---> switch ---> j-box
4 inverters ---> panel ---> switch ---> j-box
Those are both 1 system. The first has 1 source, the second has 4.
6- Yes, true. Those aren't my thing , but I do know you don't make 12 supply side connections for 12 microinverters.
7- Sure, you could have solar roof tiles on a house thru one inverter and regular panels on a garage thru another inverter, why wouldn't you combine them?
I can't see the benefit to multiple supply side connections, and that exception is just weird. I read it to say you can have a fire pump and PV on the same SECs.
supply each or several
systems covered by 230.82(5) or 230.82(6).
230.82
(5) Taps used only to supply load management devices,
circuits for standby power systems, fire pump equipment,
and fire and sprinkler alarms, if provided with
service equipment and installed in accordance with requirements
for service-entrance conductors.
(6) Solar photovoltaic systems, fuel cell systems, or interconnected
electric power production sources.
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
In my own experience, none so far. But there have been some threads on here, including recently, where the question of how many systems are allowed on premises has been raised as an issue.
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
I think I mentioned that some people make an argument (which I do not agree with) that a supply side connection for PV are not service conductors based on the definition of a service. That definition doesn't use 'supply', it uses 'delivered'. Anyway, if your larger point is that the code language is not always consistent with itself... I agree, that is true. If you want to see a list of code sections that can be used to argue 'for' and 'against' supply-side conductors for a PV system being 'service conductors', see here.
Please leave rapid shutdown out of it. First, the rapid shutdown switch may or may not be the same as the disconnecting means for the system, for more than one possible reason. Second, 705 applies to other systems besides PV, which are not required to have rapid shutdown.
Likewise. I think ggunn is correct in asking what difference it makes. Well, it might make a difference in an argument with an AHJ over whether multiple systems/sources comply with 705.12(D)(1), or 690.13(A), (B) or (D). I was trying to give you some advice that would help you as a PV integrator. As an installer I hope for a certain amount of common sense application of the rules from AHJs. For example, if I aggregate 7 inverters into a subpanel so that they can all be disconnected with one throw, I don't want to be told I haven't complied with 690.13(D) which prohibits more than 6 disconnects; I've provided one disconnect to bind them all. (Apologies to Tolkien). But neither do I want to be told that I can't put two or three inverter breakers into a panelboard that has other loads present. That's not the intent behind 705.12(D)(1). Anyway, God help me if I run into an AHJ that wants to argue the fine points as much as we are here. :lol:
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
I think that 705.12(D)(2)(3)(c) is clear on that point. It would be nice if we could use 125% of inverter current instead of breaker ratings, but that's small stuff and I try not to sweat the small stuff.
And yes, I am aware (painfully so because it happened to me) that that point has the potential of bumping a panel size up where it wouldn't have been required if it were otherwise, but it doesn't happen all that often.
PVfarmer
Senior Member
- Location
- Newport County, Rhode Island, USA
I am reading this 100% differently than you. I don't see how it has to do with putting 2 or 3 inverters into a panel with loads.
(Why not put 2 or 3 inverters into a subpanel, and use one breaker to connect sub to panel with loads?)
ALL it is trying to do is describe this 50A fused switch pictured below.
2017 is better then '14, but I still like mine.
2014--
705.12-(D)
(1) Dedicated Overcurrent and Disconnect. The source interconnection of one or more inverters installed in one
system shall be made at a dedicated circuit breaker or fusible disconnecting means.
2017-- (NOTE: it is now (B) 1, not (D) 1
Mine--
(1) Dedicated Overcurrent and Disconnect. The *point of* interconnection to a *service* of one or more PV inverter *sources* is considered the point of connection of a PV *system* and shall be made at a dedicated circuit breaker or fusible disconnecting means.
Also:
IF a PV disco is NOT a service disco, well then "you can put it inside" does NOT apply.
Which is annoying!
I think is IS and therefore you can NOT put it inside .
(1) Readily Accessible Location. The 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.
(Whoops! Disregard the ground symbol IN the panel- human error.... :slaphead
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
Have you read 705.12(D)(2)(3)(c)? It has everything to do with landing multiple inverters in a panel with loads. Whether you'd want to do it is another question entirely, but I do it all the time with load breakers on monitoring equipment and lightning arrestors in the AC combiner along with multiple inverter breakers. As long as all the breaker ratings (backfed and load excluding the one protecting the bus from the service) total to less than the bus rating, we are golden.
Before 705.12(D)(2)(3)(c), it was unclear whether a designer would have to consider the interconnection breaker when calculating the bus requirement in the AC combiner vis-a-vis the 120% rule, and some AHJs expected just that.
PVfarmer
Senior Member
- Location
- Newport County, Rhode Island, USA
Yes. But he said:
But neither do I want to be told that I can't put two or three inverter breakers into a panelboard that has other loads present. That's not the intent behind 705.12(D)(1).
And then I said:
I am reading this 100% differently than you.
2014--
705.12-(D)
(1)
I get it about D(2)(3)(c), but I wasn't talking about that one.
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
I think you are actually agreeing 100% with me. But I have seen others on this forum opine that 705.12(D)(1) requires all sources on a premise to be put through a single point of connection. That's awfully unnecessary.
(Then why did you quote him? :slaphead
PVfarmer
Senior Member
- Location
- Newport County, Rhode Island, USA
I can't quite agree with that.
705.12(D)(1) doesn't talk about a panelboard with other loads at all.....705.12(D)(2)(3)(c) does, like ggunn said.
I also don't agree with myself- now I think (D)(1) simply requires a breaker for every "source", or "inverter"...or "string of micros"...
But (1) and (2)(3)(c) are 705.12(B) now (not D) in 2017 code, 2017 changed these three green words.
705.12
(B)(1) Dedicated Overcurrent and Disconnect. Each source interconnection of one or more power sources installed in one
system shall be made at a dedicated circuit breaker or fusible disconnecting means.
Both 2017/(B)(1) and 2014/(D)(1) are referring to these 25A breakers, A and B. There could be a 4800 watt inverter on A and 18 micros on B.
That's one PV system with 2 sources.
View attachment 17273
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
Again, it seems to me that you are twisting in the wind over something that makes no tangible difference. Every inverter or branch of microinverters must have its own OCPD, obviously. When you combine two or more of the above, that combined circuit also has to have OCPD. OCPD and conductor sizing is straightforward. Whether you call it a single system or multiple systems has no bearing on how it has to be built.
PVfarmer
Senior Member
- Location
- Newport County, Rhode Island, USA
I think that's an odd opinion, because "multiple inverters" in 2014 changed to "multiple PV systems" in 2017.
And I have no clue if either of y'all will agree with the below.
If you look at the 2017 definition for PV system:
I'd say ^^ means "a single supply side connection OR a single load side PV breaker.", with nothing said about how many inverters are involved.
I'd also say 2 PV breakers into a panel with loads = 2 load side connected PV systems.
And I'd also say 2 supply side breakers or fused switches aren't allowed.
I'll stop there.
For reference:
This in 2014:
(D) Multiple Inverters. A PV system shall be permitted to
have multiple inverters installed in or on a single building
or structure. Where the inverters are remotely located from
each other, a directory in accordance with 705.10 shaH be
installed at each dc PV system disconnecting means, at
each ac disconnecting means, and at the main service disconnecting
means showing the location of all ac and dc PV
system disconnecting means in the building.
Exception: A directory shall not he required where all
inverters and PV de disconnecting means are grouped at
the main service disconnecting means.
is now 2017:
- Status