Is a parking canopy a "building"

SolarPro

Senior Member
690.12 clocks in at over 1,000 words in NEC 2017. But the title is unchanged.

As has been pointed out, there will always be 1% of AHJs who will misinterpret "on buildings" as meaning "anything built." It doesn't really matter what I think or what you think, only what the AHJ thinks. Fortunately, the majority of AHJs will get this right.
 

GoldDigger

Moderator
Staff member
690.12 clocks in at over 1,000 words in NEC 2017. But the title is unchanged.

As has been pointed out, there will always be 1% of AHJs who will misinterpret "on buildings" as meaning "anything built." It doesn't really matter what I think or what you think, only what the AHJ thinks. Fortunately, the majority of AHJs will get this right.
I think you really mean that the majority of the AHJs will get it wrong in a way that makes sense and probably supports the original CMP intent.
That is not the same as getting it right. :angel:
 

Carultch

Senior Member
690.12 clocks in at over 1,000 words in NEC 2017. But the title is unchanged.

As has been pointed out, there will always be 1% of AHJs who will misinterpret "on buildings" as meaning "anything built." It doesn't really matter what I think or what you think, only what the AHJ thinks. Fortunately, the majority of AHJs will get this right.
Do you know how to find the most recent tentative text for 690.12 in NEC2017?
 

SolarPro

Senior Member
See pp. 106-108 of this PDF:

http://www.nfpa.org/assets/files/AboutTheCodes/70/70_A2016_NEC_AAC_SCRreport.pdf

(Note how the correlating committee is striking a lot of detail from the language that made it through committee. The CMP understands how people can struggle to make sense of this requirement. The correlating committee just adds to the confusion.)

This addition will throw some water on the "PV as a building" misinterpretation espoused on this thread:

Exception: Ground mounted PV system circuits that enter buildings, of which the sole purpose is to house PV system equipment, shall not be required to comply with 690.12.
 

wwhitney

Senior Member
This addition will throw some water on the "PV as a building" misinterpretation espoused on this thread:
Changes implemented in the 2017 NEC have no bearing on the meaning of the 2014 NEC.

Regardless, if you view the breadth of the 2014 wording and definitions as an unintended technical error, then the 2017 exception addresses that, at least partially.

Now the question will be whether a carport PV system is a "ground mounted" PV system. :)

Cheers, Wayne
 

SolarPro

Senior Member
Sure. You are correct. In practice, however, I have found that AHJs are open to and interested in learning about the most recent code revisions, especially when these shed light on something that is not well clarified an earlier version and misapplied as a result.

While the exception added to 690.12 still leaves solar carports open to occasional misinterpretation, it clearly exempts ground-mounts and top-of-pole mounts and stand-alone power sheds and the like from rapid shutdown. In practice, the most important thing it does is clearly exempt ground-mounts, as this mounting method applies to such a wide swath of the market. Carports and pole-mounts are in the noise, relatively small and specialized market segments.
 

Carultch

Senior Member
See pp. 106-108 of this PDF:

http://www.nfpa.org/assets/files/AboutTheCodes/70/70_A2016_NEC_AAC_SCRreport.pdf

(Note how the correlating committee is striking a lot of detail from the language that made it through committee. The CMP understands how people can struggle to make sense of this requirement. The correlating committee just adds to the confusion.)

This addition will throw some water on the "PV as a building" misinterpretation espoused on this thread:

Thanks SolarPro.

It looks like the authors of this are intending to require module-level rapid shutdown, and then they realized that just about all modules already exceed 30 Volts open circuit. So they've imposed a 1 ft boundary instead of the 10 ft boundary, and require it to be controlled to 30V or less outside that boundary, while requiring 80 Volts or less inside that boundary. And the boundary is measured from the array edge to the enclosure, so that no matter how large the enclosure is, as long as its wall and all array conduit to it, is within 1 foot of the array, it is OK.

Good luck trying to fit it in the 1 ft limit. That is so tight that most combiners would shade the array. And you can't put the "bottom" of a string inverter against the array like that, because you will not have working space. So a lot of the 2014 solutions for rapid shutdown look like they will become obsolete.

It also looks like they're giving a 2 year grace period before imposing the module level shutdown rules.

It is good that they've clarified the point of initiation, as the way it was previously written, you could theoretically have it on your neighbor's house.
 

ggunn

PE (Electrical), NABCEP certified
I think you really mean that the majority of the AHJs will get it wrong in a way that makes sense and probably supports the original CMP intent.
That is not the same as getting it right. :angel:
In most of the solar carport structures I have designed or seen, the inverters are mounted on the support poles for the structure (therefore within 10' of the array), so whether it is or isn't a building is a non-issue.

Another case in point: here in Austin where RS is being enforced, a shade structure comprised of solar modules over the top floor of a parking garage is not required to be RS compliant.
 

Smart $

Esteemed Member
...
This addition will throw some water on the "PV as a building" misinterpretation espoused on this thread:
Exception: Ground mounted PV system circuits that enter buildings, of which the sole purpose is to house PV system equipment, shall not be required to comply with 690.12.
Throw some water on it, perhaps, but that's all. Note it will only apply to a "building" with PV being the sole purpose. A structure that also serves as a parking canopy would not satisfy the criterion.
 

jaggedben

Senior Member
Throw some water on it, perhaps, but that's all. Note it will only apply to a "building" with PV being the sole purpose. A structure that also serves as a parking canopy would not satisfy the criterion.
I'll just say that wasn't part of the intended purpose and it is not designed to serve as such. ;)
 

SolarPro

Senior Member
Intent may mean nothing to some of the volume posters on this forum, but it carries a lot of water in the real world. :thumbsup:
 

Smart $

Esteemed Member
Intent may mean nothing to some of the volume posters on this forum, but it carries a lot of water in the real world. :thumbsup:
Yeah... but quite often it's like trying to carry a pail full of water in a pail full of holes. :D
 

Carultch

Senior Member
In most of the solar carport structures I have designed or seen, the inverters are mounted on the support poles for the structure (therefore within 10' of the array), so whether it is or isn't a building is a non-issue.

Another case in point: here in Austin where RS is being enforced, a shade structure comprised of solar modules over the top floor of a parking garage is not required to be RS compliant.
You can't always guarantee that. Even if that is the general architecture of the project, there can be cases where two smaller carports are combined on one string inverter, and therefore otherwise uncontrolled DC wiring will have to be routed between the two structures.

Also, the new 2017 wording has tightened up the already tight 10 ft margin to 1 foot, which means that you can't even route uncontrolled wiring from the above an inverter to the bottom of an inverter.
 

ggunn

PE (Electrical), NABCEP certified
You can't always guarantee that. Even if that is the general architecture of the project, there can be cases where two smaller carports are combined on one string inverter, and therefore otherwise uncontrolled DC wiring will have to be routed between the two structures.

Also, the new 2017 wording has tightened up the already tight 10 ft margin to 1 foot, which means that you can't even route uncontrolled wiring from the above an inverter to the bottom of an inverter.
Of course. The NEC requirements for solar have always been (at least during my career in the business) a moving target. Every code cycle we have to adapt to the new rules.
 

ggunn

PE (Electrical), NABCEP certified
Now the question will be whether a carport PV system is a "ground mounted" PV system.
No question in my mind. A carport structure is a ground mount built tall enough for a car to park under it, not a building. Until the NEC changes the game, of course. :D
 
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