690.14 (C) (1) Photovoltaic Disconnecting Means

[SolarPro]

Once again thank you for your valuable input here.

It doesn't read "readily accessible location" It reads "first readily accessible location"...there lies the confusion.

You and the code panel know what you were thinking...but the text of the Code and an AHJ erring on the side of safety will see it differently as in the OP case.

Read it again. It it doesn't say "first readily accessible location."

It says "at a readily accessible location"

That readily accessible location could be "inside nearest the point of entrance"

Or it could be some place outside the building.

I'm not on the CMP. I just a pay attention to the Code changes and like to understand the substantiations for these.

 

[shortcircuit2]

Read it again. It it doesn't say "first readily accessible location."

It says "at a readily accessible location"

That readily accessible location could be "inside nearest the point of entrance"

Or it could be some place outside the building.

I'm not on the CMP. I just a pay attention to the Code changes and like to understand the substantiations for these.

Here is the way I read it...

Section 690.13(A) exception says...

(A) Location. The photovoltaic 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(G) shall be permitted to have the disconnecting means located remote from the point of entry of the system conductors.

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

Then 690.31(G) says...

(G) Direct-Current Photovoltaic Source and DC Output Circuits On or Inside a Building. Where dc PV source or dc PV output circuits from a building-integrated or other PV systems are run inside a building or structure,they shall be contained in metal raceways, Type MC metal clad cable that complies with 250.118(10), or metal enclosures from the point of penetration of the surface of the building or structure to the first readily accessible disconnecting means. The disconnecting means shall comply with 690.13(B), (C), and 690.15(A), (B). The wiring methods shall comply with the additional installation requirements in (1) through (4)

The exception to 690.13(A) right below the sentence that describes location says comply with 690.31(G)... So I disregard the language for location in 690.13(A) above the exception and focus on the language for location in 690.13(G)...section 690.31(G) says "first readily accessible disconnecting means". So my take on the location language in 690.13(G) is that when the DC conductors enter a building and the path or route that is chosen to run the DC conductors passes through a first readily accessible location, that's where the DC disconnect belongs.

 

[SolarPro]

Yowza. I would hate to live in that house.

Here's the deal, though.

If you're forcing people to put the PV system disconnect in the living room, kitchen, top of stairwell, upstairs hallway or whatever...who is going to use that disconnect? And how is it improving system safety? And what do you do if there are multiple subarrays entering and traveling through the building along different routes? Are you going to require a disconnect in each "first readily accessible location"?

These are parallel power generating systems. All else being equal, the power conversion system wants to be co-located with the service, and the PV system disconnect wants to be co-located with the inverter. In the Brave New World of Rapid Shutdown, first responders can control conductors within 5 or 10 feet of the array while standing in front of the electrical service and inverter.

So what exactly is the role of a dc disconnect in the customer's bedroom?

 

[ggunn]

...In a perfect world, I'd like to use SolarEdge for my home system. But I'm not sure that SunPower will let their integrator partners sell SunPower modules with a SolarEdge power conversion system.

I work for a SunPower partner, and we build SunPower/SolarEdge systems every day. PM me if you want to talk to us about a system.

 

[GoldDigger]

Applying rigorous logical analysis to the exact wording of (G), I conclude that you must continue to run metallic wireway even *past* any less accessible disconnects until you finally get to one which is readily accessible. I do not see it as requiring that first readily accessible disconnect to be installed at the first possible location!

 

[shortcircuit2]

And how is it improving system safety?

The exception to 690.14(C)(1) was added in the 2005 NEC along with 690.31(E).

Here is the substantiation for the exception to 690.14(C)(1)...

Substantiation: There are photovoltaic systems where it is physically impossible or impractical to locate a readily accessible disconnecting means at or near the point of first penetration of the conductors. This proposal refers these installations to a proposed new Section 690.31(F) that requires metal raceways and metal enclosures to be used for such circuits.


Here is the substantiation that added 690.31(F) or (E) as was the final section...

Substantiation: Building integrated photovoltaic systems (defined in a new definition in 690.2) may have multiple penetration points in the surface of a building or structure. For even a small residential system, the penetrations may number in the hundreds. It is not possible to install an accessible disconnect at each point of penetration. Keeping these dc PV source and output circuits or other dc source and output circuits from roof-mounted PV arrays in metallic raceways and or metallic enclosures from the point of penetration to the first readily accessible disconnect will meet the intent of the NEC for electrical shock and fire hazard safety for these circuits. Routing the ac outputs of remotely located utility-interactive inverters in metallic raceways or enclosures will also increase the safety of these circuits. The metallic enclosures may be needed in some systems to hold blocking diodes, overcurrent devices, and other equipment allowed in the circuits before the PV disconnect by 690.14(B). Metallic raceways and enclosures provide greater mechanical protection and fire hazard reduction than do nonmetallic raceways and enclosures for these circuits that may be energized any time the PV materials are exposed to light.

The substantiation for 690.31(E) was based on a BIPV install. The substantiation for 690.14(C)(1) claims it is physically impossible or impracticable to locate a DC disconnect at the 1st penetration. In our industry, there is always a way to design and build something, its never physically impossible or impracticable. We aren't allowed to bring normal power into a building without a disconnect at the 1st entrance location, even in a bedroom, or in a large facility with multiple service locations. So why allow it for PV? I tell you what the result is...New Jersey at the Delanco Dietz & Watson meat factory...many fire fighters are going to think about risking their lives to fight a fire to save a building when there is live power on or in a building that they can't disconnect. It doesn't matter if its in a metal raceway to them...there is dangerous power in or on that building.

 

[jaggedben]

First we have language in 690.14(C)(1) that says..."nearest the point of entry" and then we have language 690.31(E) that says..."first readily accessible location"

shortcircuit, with respect, you are carrying a simple misreading of the language to a totally unwarranted conclusion. The code simply does not say "first readily accessible location", anywhere. The language in 690.31(G) is "first readily accessible disconnecting means."

In other words, you can take the 690.31(G) compliant method as far from the array as you like, as long as it ends in a disconnecting means in a readily accessible location. Whatever that location happens to be, it is 'the first readily accessible disconnecting means'. From there, if you like, you can continue it with a non-690.31(G) compliant method (not that I ever would, for reasons alluded to in this thread). Regardless of the safety theory behind this, this is what the code currently says.

As far as fire departments logic:
a) what Solar Pro said. How are firefighters going to find an inside disconnect on the upper floors of a building, especially a multi-story one? A rooftop disconnect requirement makes sense. Any disconnect that is inside that is not at ground level makes little sense as a safety practice.
b) This argument is likely to be moot after the 2017 NEC comes out. Since rapid shutdown takes of it, the sections we are arguing about will be deleted from the 2017 NEC if the First Draft language sticks. An informational note will explain as much.
c) If firefighters are going to act that scared and ignorant of PV in a given case, then it makes little difference what disconnects exist, required or not.

...But I'm not sure that SunPower will let their integrator partners sell SunPower modules with a SolarEdge power conversion system.

Drifting totally off topic here, but ... I believe that the positive grounding required by Sunpower to prevent PID would make them incompatible with Solaredge and many other newer inverters. No?

 

[SolarPro]

Yes, I was wondering about that myself. But Gordon's comment is consistent with the research I did about a year ago.

It does seem like some SunPower dealers have more flexibility w/ regards to BOS vendors than others, which may boil down to sales volume.

 

[info@sunrocksolar.com]

Escalating this to our local chief inspector

Escalating this to our local chief inspector

Thanks for the thoughtful replies and information. We are on the 2011 code at present. I think the substantiations from the code cycle review are insightful. I submitted some of the information provided here to my local chief inspector for consideration. I believe him to be a very knowledgeable and intelligent man and expect he will at least take time to read the attachments and comments I have forwarded. I will let you know how this comes out.

 

[rainwater01]

I know this is an old thread but it's still applicable to me. Indiana is still on the 2008 NEC. I have solar on the roof of a detached garage and I have a disconnect and fuse protection at a readily accessible location inside of it. If I run the PV wires in PVC conduit from the garage to the house do we have to transition back to metal conduit until we get to the first dc disconnect in the house? I feel like the purpose of the code was for protection of the PV wires until they reach overcurrent protection which I will have already done in the garage.

 

[jaggedben]

I know this is an old thread but it's still applicable to me. Indiana is still on the 2008 NEC. I have solar on the roof of a detached garage and I have a disconnect and fuse protection at a readily accessible location inside of it. If I run the PV wires in PVC conduit from the garage to the house do we have to transition back to metal conduit until we get to the first dc disconnect in the house? I feel like the purpose of the code was for protection of the PV wires until they reach overcurrent protection which I will have already done in the garage.

Wow 2008 NEC. That is ancient times for solar. (You dont have rapid shutdown, but good luck with grounding.)

I assume you are talking about DC conductors since the rule does not apply to AC conductors, although I can't recall how clear that was in the 2008.

I would say that you still need a disconnect, although I don't think it's the situation the code is intended to address. However the point is that if fire fighters are chopping through the building they are supposed to have some extra protection when dealing with conductors that are potentially live even when all disconnects are shut off.

It's important to understand that overcurrent protection has nothing to do with it, because PV conductors are sized for more current than PV panels on that circuit can really throw at them. Overcurrent protection will never shut down a PV circuit that has shorted, it will only keep other larger sources (such as multiple paralled strings) from feeding that short.

 

[rainwater01]

Yeah, this one’s dc all the way to the inverter/charge controllers. Good call on the overcurrent protection. Thanks!


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