California Rapid Shutdown Requirements

[pgrovetom1]

When neither a ground mount solar string array and the inverters are located within 50 ft of a building ( both outdoors), are panel rapid shutdown devices required in California. The solar array is mounted on a gentle hillside on a steel frame with 18" underground conduits carrying the DC string pairs to the Inverter. The Inverter has a built in and labeled DC disconnect. The inverters are mounted on a pressure treated wood post structure similar to the utility post intended to provide some sun/weather protection and a place to physically mount the inverters and there are 3 Tesla Powerwall2's mounted on a concrete pad. The PG&E utility power arrives underground to a 4x6" pole mounted 400A panel which acts as the place where the inverter/battery system meets the AC wires that go to the home via underground approximately 50 ft conduits that have multiple sub-panels inside the home. The AC power from the inverter/Powerwall2 battery system are carried via a trough system to the utility 4x6" post. The utility comes up the 4x6" post up from underground. The AC for the home goes via conduits down the 4x6" post and underground to the home. So neither the inverters nor the ground mount solar arrays DC penetrates the home in any way. It does not come within 50 feet of the home. Only the AC from the utility or inverters penetrate the home via conduits as it was before the solar was installed. The NEC language suggests this situation does not require a rapid shutdown function for the solar arrays.

This system was permitted and built in 2019. The reason I am asking is I'm thinking of adding an additional ground mount array and another inverter. If I do this will it now require the array rapid shut down function given there has been 2 NEC updates since 2019 with slightly different language. thanks

 

[ActionDave]

Forum rules prevent us from giving DIY. Provided you are not doing the work yourself someone here can answer your question about code requirements.

 

[jaggedben]

No rapid shutdown is required in this scenario and that has not changed between when it was installed and now.

 

[pgrovetom1]

I'm not planning on doing the work myself via DIY. But I'm trying to do my homework in advance so I know what I'm in for. I could just get bids from solar companies but it seems to make sense to understand in advance if new requirements would add significant issues for both the new portion or even be retroactive to my 2019 system. The NEC is not written in a straightforward manner and simple things like the definition of the word "building" can mean anything. Is a 4x6" post based mount a building or is a steel array ground mount a building? I trust competent electricians that are found here more than solar installation companies that I believe could be incentivized to maximize their profit or business approach beyond what might happen if I was better educated as to the needs.

My existing system was designed and installed by Tesla which is no longer an option given they have changed their architecture to the PowerWall3 and even their way of doing business in retrofits. I'm not sure what you mean by DIY but to me its doing the work myself which I'm not in a position to do. But I have heard horror stories of people who went into systems without knowing specifics which could have a large impact on feasibility and cost or even practicality. By educating myself on the specifics of things like the latest post 2019 rapid shutdown requirements and other things yet investigated, only makes sense.

For example, would the new requirements be retroactively applied to my existing solar arrays such that its not economically feasible. I've had non-solar or electrical situations where the local building department required older but permitted things to be retroactively brought up to code causing many problems. I would like to know from experts if I might run into this kind of situation on having my solar system expanded and whether its a small or big deal, retroactive or not. Hopefully that explains why I asked the question and hopefully education doesn't violate rules if not for the purpose of DIY. thanks for any help educating me prior to reaching out to solar companies.

 

[pgrovetom1]

Forum rules prevent us from giving DIY. Provided you are not doing the work yourself someone here can answer your question about code requirements.

thanks

 

[jaggedben]

It is rare for jurisdictions to retroactively apply new requirements to existing installations, and extremely rare if the installation was recently permitted and approved. In any case there's no such requirement at issue here.

The NEC definition of a building is indeed poor and confusing, but to my knowledge no one interprets it to apply to a ground mounted array. (For one thing, what would be the point of limiting the rapid shutdown requirement to buildings if any PV mounting structure were a building?) For what it's worth the 2023 NEC clarifies this and jurisdictions will sometimes let the future code cycle clarify ambiguities in the current code.

 

[wwhitney]

Also, the 2020 NEC, in force in CA, has the necessary exception to 690.12: "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."

https://up.codes/viewer/california/ca-electric-code-2022/chapter/6/special-equipment#690.12

That is, if you want to interpret "buildings" expansively enough to cover the standalone equipment support structure, you might as well also interpret "enter" to cover the way the conductors interact with that "building." Although really, the exception should start out "Ground-mounted PV system circuit in or on buildings, . . ." for parallelism with how 690.12 starts.

Cheers, Wayne

 

[ggunn]

It is rare for jurisdictions to retroactively apply new requirements to existing installations, and extremely rare if the installation was recently permitted and approved.

But it is not unusual for an AHJ to require that any additional equipment installed in an existing system after a rules change conform to the new rules, and if the interconnection is changed, that it also be made compliant with the new rules. I have also encountered cases where a customer's service was required to be brought up to current code when a PV system was installed, even when the PV system was load side connected in an existing MDP.

 

[jaggedben]

But it is not unusual for an AHJ to require that any additional equipment installed in an existing system after a rules change conform to the new rules, and if the interconnection is changed, that it also be made compliant with the new rules. I have also encountered cases where a customer's service was required to be brought up to current code when a PV system was installed, even when the PV system was load side connected in an existing MDP.

Ok, but I was addressing his question of whether the existing arrays would be subject to rapid shutdown rules. He is basically talking about installing a new additional system, not modifying the existing system.

 

[ggunn]

Ok, but I was addressing his question of whether the existing arrays would be subject to rapid shutdown rules. He is basically talking about installing a new additional system, not modifying the existing system.

It's a moot point, anyway, isn't it?

 

[pgrovetom1]

Ok, but I was addressing his question of whether the existing arrays would be subject to rapid shutdown rules. He is basically talking about installing a new additional system, not modifying the existing system.

That's correct. The only place they would meet is at the solar/PW panel with a new breaker for the new array and its inverter. The only overlap would be verifying the existing 200A panel could accept the new load.