Is it a PV Disconnect or a PV Service Disconnect?

jaggedben

Senior Member
Please describe how the title to Part VI relates to 230.70. Additionally, what word precedes each instance of disconnect, or derivations thereof, in every subsection of 230.70?
You are begging the question. The point is that the 'General' section of 230.70 strongly implies that a PV system disconnect that is connected directly to service entrance conductors is a 'service disconnecting means' because it doubles as all or the part of the 'means...provided to disconnect all conductors ... from the service entrance conductors.'

230.70 is one of several sections of 230 I could have mentioned which are written as if it is a fact that the disconnect and conductors for a supply-side-connected PV system are a 'service disconnect' and 'service conductors'. There's also 230.2(A)(2), 230.40 Exception 5, and 230.71(A) (already mentioned). True, thereare other sections (the definition of a 'service', and the various "supply side of the service disconnecting means' sections) that can be read to mean the opposite. This simply means we have conflicting and inconsistent language in the code. This should not come as shock, since knowledgeable people have been disagreeing on this particular subject for a while now.

For me, what settles the question is none of these particular sections, but rather 90.1(A). Service-entrance-conductors which are connected to a PV system present exactly the same safety hazards as any other service entrance conductors. Therefore, generally speaking, they should treated as such and subject to all the same rules.

Man, you're really pushing the envelop to make your point :happyyes:. Installing the disconnect in a readily accessible location has very little to do with the disconnect being located outside the building or inside adjacent the conductor entry point....
Again, I think you're begging the question (or I am not understanding your contention). The question is whether there are any location requirements with respect to the inside and outside of buildings for AC PV system disconnects. My contention is that there are not, unless they happen to also be service disconnects which fall under 230.70. You are contending that there are requirements, and they are covered by 690.14, which is an opinion which I disagree with, but which you've made some reasonable comments in support of. You also seem to be contending (am I wrong?) that there ought to be location requirements with respect to the inside and outside of buildings for AC PV system disconnects. That's a separate opinion, also one I disagree with, but one which I don't believe you've offered any supporting argument for in this thread.

So an Inverter Output Circuit is excluded from Article 690 requirements? Refer to definitions of 690.2.
Of course not. There are several sections of 690 that have specific requirements for inverter output circuits. However I will add that none of them, to my knowledge, describe these circuits as 'photovoltaic' or part of a 'photovoltaic system'.
Believe as you may... but as long as you continue this path, I will disagree. :jawdrop:
Well, you are entitled to your opinion. :D
I'm really at a loss in understanding this comment, much less offer a response... :?
It was simply an expression of my hope that 690.14 has made things clearer in the 2014 NEC.

The only thing I can surmise is that you like to debate the issues.... :cool:
I also like the rules that I have to work by to be clear, logical, and to have a legitimate reason for existing. (Again, see 90.1(A).) Often naive, to be sure, when dealing with the NEC, but still worth shooting for.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
Backing up out of the trees for a moment to get a better look at the forest?

With the rapid growth of solar and the large number of medium to large scale systems being built, this situation is far more common now than it has been in the past. It would be great if the NEC would address it directly in one concise section rather than making it necessary to go from Article to Article and sift through reams of requirements which may or may not apply depending on interpretation to try to figure out what is or is not compliant. Hence this discussion. I'm just saying'.
 

SolarPro

Senior Member
Location
Austin, TX
690.14 does get a lot simpler in NEC 2014, because it is eliminated altogether?and replaced by sections 690.13 and 690.15.

Here is the language for 690.13:

III. Disconnecting Means

690.13 Building or Other Structure Supplied by a Photovoltaic System

Means shall be provided to disconnect all un grounded dc conductors of a PV system from all other conductors in a building or other structure.

(A) Location. The PV disconnecting means shall be installed at a readily accessible location either on the outside of a building or structure or inside nearest the point of entrance of the system conductors.

Exception: Installations that comply with 690.31(F) shall be permitted to have the disconnecting means located remote from the point of entry of the system conductors.

The PV system disconnecting means shall not be installed in bathrooms.

Explanatory text from Handbook: These requirements generally prohibit long runs of PV source and output circuits inside a building before reaching the required PV disconnect. A short conductor run through a wall at the point of first penetration to reach a disconnect mounted inside the building is allowed. Section 690.31(G) permits these circuits to be run inside a building where installed in metal conduit from the point
of entrance to the system disconnecting means.

(B) Marking. Each PV system disconnecting means shall be permanently marked to identify it as a PV system disconnect.

(C) Suitable for Use. Each PV system disconnecting means shall not be required to be suitable as service equipment.

(D) Maximum Number of Disconnects. The PV system disconnecting means shall consist of not more than six switches or six circuit breakers mounted in a single enclosure or in a group of separate enclosures.

(E) Grouping. The PV system disconnecting means shall be grouped with other disconnecting means for the system in accordance with 690.13(D). A PV disconnecting means shall not be required at the PV module or array location.

Explanatory text from Handbook: Where a building has multiple sources of power, such as the utility, the PV array, backup generator, and wind system, no more than six disconnects for each source of power to the building are permitted, and the disconnects for each source are required to be grouped together.
 

SolarPro

Senior Member
Location
Austin, TX
And here is the language for 690.15:

690.15 Disconnection of Photovoltaic Equipment

Means shall be provided to disconnect equipment, such as inverters, batteries, and charge controllers, from all ungrounded conductors of all sources. If the equipment is energized from more than one source, the disconnecting means shall be grouped and identified.

A single disconnecting means in accordance with 690.17 shall be permitted for the combined ac output of one or more inverters or ac modules in an interactive system.

(A) Utility-Interactive Inverters Mounted in Not Readily Accessible Locations. Utility-interactive inverters shall be permitted to be mounted on roofs or other exterior areas that are not readily accessible and shall comply with 690.15(A)(1) through (4):
(1) A dc PV disconnecting means shall be mounted within sight of or in each inverter.
(2) An ac disconnecting means shall be mounted within sight of or in each inverter.
(3) The ac output conductors from the inverter and an additional ac disconnecting means for the inverter shall comply with 690.13(A).
(4) A plaque shall be installed in accordance with 705.10.

(B) Equipment. Equipment such as PV source circuit isolating switches, overcurrent devices, dc-to-dc converters, and blocking diodes shall be permitted on the PV side of the PV disconnecting means.

Explanatory text from Handbook: In general, equipment that needs servicing must be disconnected from sources of supply. In a PV system, however, some equipment is permitted to be located on the PV power source side of the disconnecting means. See Exhibit 690.11. Servicing the exempted equipment might require disabling all or portions of the array as explained in the commentary following 690.18.
A disconnecting means located in each PV source circuit or located physically at each PV module location is not required. Unlike load circuits (such as rooftop air conditioners), PV source-circuit conductors may be energized at any time from the PV modules. A centrally located disconnect meeting the requirements of 690.13(A) near the inverter or batteries serves to disconnect the PV source circuits from the other portions of the electric power system.

(C) Direct-Current Combiner Disconnects. The dc output of dc combiners mounted on roofs of dwellings or other buildings shall have a load break disconnecting means located in the combiner or within 1.8 m (6 ft) of the combiner. The disconnecting means shall be permitted to be remotely controlled but shall be manually operable locally when control power is not available.

(D) Maximum Number of Disconnects.
The PV system disconnecting means shall consist of not more than six switches or six circuit breakers mounted in a single enclosure or in a group of separate enclosures.
 

Smart $

Esteemed Member
Location
Ohio
You are begging the question. The point is that the 'General' section of 230.70 strongly implies that a PV system disconnect that is connected directly to service entrance conductors is a 'service disconnecting means' because it doubles as all or the part of the 'means...provided to disconnect all conductors ... from the service entrance conductors.'

230.70 is one of several sections of 230 I could have mentioned which are written as if it is a fact that the disconnect and conductors for a supply-side-connected PV system are a 'service disconnect' and 'service conductors'. There's also 230.2(A)(2), 230.40 Exception 5, and 230.71(A) (already mentioned). True, thereare other sections (the definition of a 'service', and the various "supply side of the service disconnecting means' sections) that can be read to mean the opposite. This simply means we have conflicting and inconsistent language in the code. This should not come as shock, since knowledgeable people have been disagreeing on this particular subject for a while now.

For me, what settles the question is none of these particular sections, but rather 90.1(A). Service-entrance-conductors which are connected to a PV system present exactly the same safety hazards as any other service entrance conductors. Therefore, generally speaking, they should treated as such and subject to all the same rules.



Again, I think you're begging the question (or I am not understanding your contention). The question is whether there are any location requirements with respect to the inside and outside of buildings for AC PV system disconnects. My contention is that there are not, unless they happen to also be service disconnects which fall under 230.70. You are contending that there are requirements, and they are covered by 690.14, which is an opinion which I disagree with, but which you've made some reasonable comments in support of. You also seem to be contending (am I wrong?) that there ought to be location requirements with respect to the inside and outside of buildings for AC PV system disconnects. That's a separate opinion, also one I disagree with, but one which I don't believe you've offered any supporting argument for in this thread.
Ultimately, I could care less if you want to install a supply-side disconnect under the requirements of Article 230. Keep in mind that if you do, the disconnect(s) must be, but not limited to, rated as suitable for use as service equipment [230.66], permanently marked to identify it as a service disconnect [230.70(B)], and must be counted in the two-to-six grouping requirement [230.71, 230.72]. What if the Inverter Output Circuit(s) never enter a building or other structure. Are you still going to install the disconnect as a Service Disconnect? Furthermore on this issue, I seem to recall you favored such disconnect not having to be "service rated" under 690.14(A). You are not permitted to have selective amnesia... :blink:


Of course not. There are several sections of 690 that have specific requirements for inverter output circuits. However I will add that none of them, to my knowledge, describe these circuits as 'photovoltaic' or part of a 'photovoltaic system'.
Appears to be another selective amnesia interpretation ;)

Just the fact that inverter output circuit is defined in Article 690 makes it part of the Article title subject... which BTW is "SOLAR PHOTOVOLTAIC (PV) SYSTEMS". But if that still does not convince you, perhaps Figure 690.1(B) Identification of Solar Photovoltaic System Components in Common System Configurations will. If you still need more, just let me know... :bye:
 

jaggedben

Senior Member
What if the Inverter Output Circuit(s) never enter a building or other structure. Are you still going to install the disconnect as a Service Disconnect?
Yes.

Furthermore on this issue, I seem to recall you favored such disconnect not having to be "service rated" under 690.14(A).
You are not permitted to have selective amnesia... :blink:
You are mistaken, so I don't need that permission. :p

Just the fact that inverter output circuit is defined in Article 690 makes it part of the Article title subject...
So? The way 690 defines the inverter output circuit, it logically includes all subpanel feeders and similar conductors that might be between the inverter and the service disconnecting means. It's flat out silly to claim these are all part of the PV system. Are all the disconnects for such feeders PV system disconnects? Are they all required to be noted on the plaque in 690.56(B)?

(I just noticed that the last bit of the inverter output definition is actually ungrammatical as well.)

... But if that still does not convince you, perhaps Figure 690.1(B) Identification of Solar Photovoltaic System Components in Common System Configurations will. If you still need more, just let me know... :bye:
I'm unmoved by the diagram, notably because the term 'photovoltaic' doesn't appear on the AC side of the inverters. I've acknowledged that my interpretation is an interpretation, which means I fully acknowledge that I'm doing the best I can with language that I believe is intractably vague. When it doubt, I'm falling back on 90.1(A).
 
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jaggedben

Senior Member
690.14 does get a lot simpler in NEC 2014, because it is eliminated altogether?and replaced by sections 690.13 and 690.15.

Here is the language for 690.13: ...
And here is the language for 690.15:

...
Thank you! Maybe I'll order my copy of the 2014 NEC when I'm done with the forum tonight. :D

I do think that my interpretation of the requirements is a lot easier to argue for under the 2014 NEC.
 

c_picard

Senior Member
Location
USA
Been down the rabbit hole...

Been down the rabbit hole...

..and back up again. Great thread, folks.

It should be noted that this topic cannot be adequately discussed in a historical vacuum. Mr. Wiles has tried to get the language in 690, and 705, to explicitly reference Article 230 in regards to supply side connections, and the disconnect requirements thereof. (Similar to language found in 695). The CMP's have summarily dismissed the proposals with some illuminating commentary. They basically said that the proposals were not necessary, because it was already made crystal clear in other parts of the code that this was the intent. Bad call, fellers.

Also, let's all remember why it is that we bond the grounded conductor at service enclosures in the first place. It is not safe to wholly discard the requirements of 230, simply because we cannot agree on what to call this disconnect. (Platypus?)

To be perfectly candid, I'm familiar with PV system installations in several hundred jurisdictions (at least), and there are 3, yes, three that I am aware of, that prohibit the grounded conductor from being bonded at the newly added platypus. Please don't be the fourth guy. This debate is not nearly as polarized as this thread would have us believe; the overwhelming majority understand that the code is a bit muddy, but the intent is clear. This disconnect should be treated as a service disconnect.

All in favor? and the 'ayes' have it.
 

texie

Senior Member
..and back up again. Great thread, folks.

It should be noted that this topic cannot be adequately discussed in a historical vacuum. Mr. Wiles has tried to get the language in 690, and 705, to explicitly reference Article 230 in regards to supply side connections, and the disconnect requirements thereof. (Similar to language found in 695). The CMP's have summarily dismissed the proposals with some illuminating commentary. They basically said that the proposals were not necessary, because it was already made crystal clear in other parts of the code that this was the intent. Bad call, fellers.

Also, let's all remember why it is that we bond the grounded conductor at service enclosures in the first place. It is not safe to wholly discard the requirements of 230, simply because we cannot agree on what to call this disconnect. (Platypus?)

To be perfectly candid, I'm familiar with PV system installations in several hundred jurisdictions (at least), and there are 3, yes, three that I am aware of, that prohibit the grounded conductor from being bonded at the newly added platypus. Please don't be the fourth guy. This debate is not nearly as polarized as this thread would have us believe; the overwhelming majority understand that the code is a bit muddy, but the intent is clear. This disconnect should be treated as a service disconnect.

All in favor? and the 'ayes' have it.
Aye. Of course you know my position anyway.

I just fall back on the electrical reality of this. If you draw the circuit out and consider what happens in a fault of a conductor in said disconnect directly connected to the service conductors the conclusion is obvious....better have the neutral bonded or there maybe bad results. And I agree that this requirement is implied, just not spelled out but should be.

Let the debate begin....
 

jaggedben

Senior Member
Aye.

This might belong in another section of the forum, but I would suggest that the confusion might be (largely) cleared up with a couple minimal code changes.

1) Change the definition of a service, replacing 'from...to' with 'between...and' respectively.

2) Wherever the phrase 'supply side of the service disconnecting means' or similar is used, replace with '...normal service disconnecting means.'
 

c_picard

Senior Member
Location
USA
That would be helpful.

I've been thinking about this subject quite a bit lately, and I am working on mapping out the logic chain. The goal is to pinpoint exactly where the breakdowns are occurring.

Recall that this thread began with a false dichotomy, two "experts" calling it differently. I really appreciate what Mike has done for the electrical industry, but I wouldn't ask Mr. Wiles to wire my swimming pool, if you know what I mean.

I'll share the logic chain as soon as its finished. Perhaps we can bump this over to the proposal thread.

Sent from my SCH-I535 using Tapatalk
 

shortcircuit2

Senior Member
Location
South of Bawstin
Recall that this thread began with a false dichotomy, two "experts" calling it differently. I really appreciate what Mike has done for the electrical industry, but I wouldn't ask Mr. Wiles to wire my swimming pool, if you know what I mean.
I'm not sure what you mean...Mr. Wiles said nothing about wiring a swimming pool?

John Wiles is an expert when it comes to Solar Photovoltaics...

I agree Mr. Holt has done much for the electrical industry too. But sometimes he puts his own opinion on issues instead of staying on course with what the code specifies...this dichotomy generates polarity within our industry that resulted in this thread.
 

c_picard

Senior Member
Location
USA
Ha. I was subtly implying that I do not consider Mr. Holt a PV expert. But I do think he has a solid grip on the pool article!

Sent from my SCH-I535 using Tapatalk
 

Zee

Senior Member
Location
CA
..and back up again. Great thread, folks.

It should be noted that this topic cannot be adequately discussed in a historical vacuum. Mr. Wiles has tried to get the language in 690, and 705, to explicitly reference Article 230 in regards to supply side connections, and the disconnect requirements thereof. (Similar to language found in 695). The CMP's have summarily dismissed the proposals with some illuminating commentary. They basically said that the proposals were not necessary, because it was already made crystal clear in other parts of the code that this was the intent. Bad call, fellers.

Also, let's all remember why it is that we bond the grounded conductor at service enclosures in the first place. It is not safe to wholly discard the requirements of 230, simply because we cannot agree on what to call this disconnect. (Platypus?)

To be perfectly candid, I'm familiar with PV system installations in several hundred jurisdictions (at least), and there are 3, yes, three that I am aware of, that prohibit the grounded conductor from being bonded at the newly added platypus. Please don't be the fourth guy. This debate is not nearly as polarized as this thread would have us believe; the overwhelming majority understand that the code is a bit muddy, but the intent is clear. This disconnect should be treated as a service disconnect.

All in favor? and the 'ayes' have it.
Aye.
It's a service disconnect.... for PV. Just like a service disconnect for a home.
Whether we call it - and label it -
PV SERVICE DISCONNECT or just
SERVICE DISCONNECT
doesn't get me riled up.
 
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