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Rapid Shutdown Requirement for CA Permitting

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TheHappyNomads

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In preparation of submitting a permit application for the PV system I'm constructing I will need a rapid shutdown switch of some kind

-OR-

"IF ANOTHER MEANS OF RAPID SHUTDOWN IS NOT PRESENT, PROVIDE A ROOFTOP DC DISCONNECT * @ ROOF WITHIN 3’ OF PV ARRAY ALONG ACCESS PATHWAY PER HAYWARD FIRE ORDINANCE."

After looking around the rapid shutdowns available are ~$800-$1000. I'm not sure how much a DC Disconnect would run. At the price point of the shutdown switch at least would it be more worthwhile to explore micro-inverters instead? If so, then how to do those play with ALL-in-1 inverter controllers like the LV6548s I have?
 
You would need to get into AC coupling if you use microinverters. The Hybrids would then have a $1000-1500 MPPT that you aren't using. Feelsbad. But it may be the right way if you have heavy shading (but if you have heavy shading why are you using solar).

Rapid shutdown without optimizer is $20 per module and $100 for the transmitter (which can be used with multiple strings), plus balance of system. Microinverter is $60-70 per panel if you don’t use Enphase and instead use multiport modules from the Chinese solar companies (NEP, as in North East China, as in Shandong; Hoymiles; etc). They’re on the CEC list, pickable from the PG&E application, so perfectly fine to install in California.

LV6548 and its ilk that are non UL non CEC and "permitted install in California" is an oxymoron.
 
zanydroid said:
LV6548 and its ilk that are non UL non CEC and "permitted install in California" is an oxymoron.
Click to expand...

Does this only pertain to grid-tied systems? My build isn't going to be grid tied. My purpose for permitting is to not run into homeowner's insurance issues. Maybe I'm thinking incorrectly about this then...
 
TheHappyNomads said:
Does this only pertain to grid-tied systems? My build isn't going to be grid tied. My purpose for permitting is to not run into homeowner's insurance issues. Maybe I'm thinking incorrectly about this then...
Click to expand...
Not sure. I think CEC only covers grid tie.

Off-grid you are still subject to California Residential code but I imagine not CEC or PG&E. That requires UL9540 for a system with batteries. The LV6548 is not even UL1741 if i'm not mistaken, and there are only a few approved combinations of UL9540. Which is a inverter and battery tested at the same time by UL or other lab. California explicitly requires this variant of 9540.
 
Note: If you connect a hybrid that parallels inverter to AC-input (a lot of them) then you are still subject to PG&E since you are operating a generation facility with output paralleled with PG&E grid..
 
Well... crap...

My plan was to have the panels and LV6548s direct to ESS which would then service my subpanel (all loads are wired/will be wired in this). Dedicated circuit from main panel to LV6548s to charge ESS when PV is insufficient.
 
Not clear what SLD you have in mind. Some of the terminology you use ("Direct to ESS") is confusing. You mean direct to battery? ESS as defined in my head is IIRC inverter + battery (and possibly also SCC).

NEC:
Energy Storage System (ESS). One or more components assembled together capable of storing energy for use at a future time. ESS(s) can include but is not limited to batteries, capacitors, and kinetic energy devices (e.g., flywheels and compressed air). These systems can have ac or dc output for utilization and can include inverters and converters to change stored energy into electrical energy.



Talk to AHJ before buying anything. This stuff is expensive overall and expensive to return.

If you think you'll want to do something lower risk but not strictly code compliant, you may not want to tip your hand with AHJ.

Actually maybe the LV6548 is UL1741. If its AC output never touches grid and it is not used as ESS you might be fine.
 
zanydroid said:
Yeah, which sort of makes using an AIO less point-ful. You need to use a battery-less one. Nice for taking the edge off AC bills I guess.
Click to expand...
Without batteries, it sounds like a bunch of wasted solar power if it is only able to cover loads underneath it. You would really struggle to achieve any type of payback on that. You would have to have received all your equipment for free practically. :ROFLMAO:
 
Note also feeding a non-ESS AIO into a hybrid will require the AIO to support AC coupling. That is certainly not the default because AIO is off grid so it might be presumed to not have frequency watts modulation.

Also not all AIO are able to operate battery-less. A few do. Most hybrids probably are because they can also operate as grid tie (though I guess there could always be the odd one out there whose SCC or MPPT refuses to start if there’s no battery)
 
TheHappyNomads said:
Plan on using LV6548s to charge ESS battery bank that will feed AC loads in subpanel currently fed by a 90a breaker from main panel
Click to expand...

What product(s) is the ESS battery bank? That will need to be UL9540 or hidden from insurer/AHJ

Are LV6548 able to operate battery less?

How do you plan to transfer back to grid if you are out of battery?
 
Last edited:
zanydroid said:
What product(s) is the ESS battery bank? That will need to be UL9540 or hidden from insurer/AHJ
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I asked the question of AHJ about DIY ESS and they simply stated that I would need to include the total capacity and spec sheet for the batteries. They did not mention anything about UL9540.
zanydroid said:
How do you plan to transfer back to grid if you are out of battery?
Click to expand...
I believe that the LV6548s can be wired as a load from the main service panel to address this.
 
TheHappyNomads said:
I asked the question of AHJ about DIY ESS and they simply stated that I would need to include the total capacity and spec sheet for the batteries. They did not mention anything about UL9540.
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Did you look in municipal code to see if they amended residential code to remove the requirement? At state level there is a DIY exemption if you use recycled EV hardwar for the batteries and store the batteries in some specific type of location.

Since what they told you contradicts state law (unless amended) and batteries are quite expensive I wouldn't buy anything until you get your plans stamped by the city. In my city what I expect to happen is that the firm contracted to review would reject it citing that residential code provision. And then when I fix it they will force me to quote that provision directly on the signed plans to give more rope to hang me. They force this for me on much simpler code provisions. Like exactly how kitchen outlets need to be done.
 
zanydroid said:
Did you look in municipal code to see if they amended residential code to remove the requirement? At state level there is a DIY exemption if you use recycled EV hardware for the batteries and store the batteries in some specific type of location.
Click to expand...
I have not, but I will look this weekend.

zanydroid said:
Since what they told you contradicts state law (unless amended) and batteries are quite expensive I wouldn't buy anything until you get your plans stamped by the city. In my city what I expect to happen is that the firm contracted to review would reject it citing that residential code provision. And then when I fix it they will force me to quote that provision directly on the signed plans to give more rope to hang me. They force this for me on much simpler code provisions. Like exactly how kitchen outlets need to be done.
Click to expand...
I'll explore this more closely this weekend. Thanks for the insights
 
TheHappyNomads said:
I have not, but I will look this weekend.
Click to expand...
OK cool. The residential code also has good sections on how to protect the batteries from getting smacked by a car. There should be pictures in the code book or the sites for explaining the codebook on where they should be placed in a garage. I don't know who's building bollards into their garage though to protect batteries as those diagrams say you should/need to do (I guess it means the batteries need to be placed in the locations exempt from it, or that's more for multi-family parking structures).
 
I used TIGO for my rapid shutdown system. Pretty painless setup and all is well so far.

www.tigoenergy.com

Tigo TS4-A-2F

The Tigo TS4-A-2F is a reliable, cost effective rapid shutdown solution that meets the latest module level shutdown requirements, including NEC 2017/2020. The TS4-A-2F is both IEC and UL certified for global acceptance. It is UL PVRSS certified for connectivity with the largest network of...
www.tigoenergy.com www.tigoenergy.com

signaturesolar.com

Tigo Single Core RSS Transmitter (100A), Din Rail, 120/240VAC PS, Outdoor Enclosure

Signature Solar provides solar panels, off-grid solar systems, grid-tie, and hybrid systems. Quality solar inverters, bifacial solar panels, complete solar kits, solar batteries. Featuring brands such as EG4 Electronics with their solar battery, LifePower4 and EG4 LLifePower4 and EG4 LL
signaturesolar.com signaturesolar.com
 
TheHappyNomads said:
Seems like a pretty cool product and would solve the problem. How many of the modules did you need to purchase for your setup?
Click to expand...
Tigo offers them for single panels and pairs of panels (two panels for one RSD module)

The RSD module for 2 panels puts the two panels in series.
 
I did the 2 solar panel RSD modules and have 8 RSD modules on my roof. The leads were plenty long enough to series connect the modules, but I did have to make some wires up to get my solar panel wiring to reach the RSD modules. I learned the difference between solar panels with portrait wires and solar panels with landscape wires :ROFLMAO:

One array is 6 panels in series, the other is 10 panels in series. Both positive wires run through the coil on the transmitter and into their respective charge controllers. Startup happens within about 10 seconds and shutdown is within 20 or so seconds. So far, I am very happy with the product. My only concern is longevity given the brutal conditions the modules are exposed to but time will tell. If one module fails, I don't really know how to easily diagnose it. Not going to be fun, I assume.
 
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