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Santa Clara County retroactively Changing ESS Rules
- Thread starter Vines
- Start date
I’m still amazed that CPA was still allowing stacked Powerwalls that late in 2020... I don’t think any Bay Area AHJ allows that now.
So no stacked pw's? I know my design was started that way and only changed since I did not want stacked for the extra space they took
That is great! Horrible that we should be excited about actually following the law, but I am glad it worked out well.
All the best,
BG
We have stacked PWs installed on an exterior West facing wall in Belmont (adjacent to San Mateo and San Carlos). The permit was issued October 22, 2020, and inspection was completed in mid December. The PWs are 1" from exterior stucco, and are separated from each other with nice looking hardware about 1.25". The permit shows a diagram of the "Powerwall unit" with details on how to attach to studs. The cutsheet shows the PWs are actually two separate units.
The majority of Bay area jurisdictions still allow stacked batteries. July 1 2021 this will change.
How so? Is this if that certification you mentioned earlier doesn’t come in or is this based on something else?
So many people who didn’t order last year and waited until this year I could see being affected and if stacking is going to be prohibited it will cut down on PWs able to be ordered and installed. Think free wall space for most people is limited in general in homes here due to lot/house sizes. My husband has a co-worker who just placed a Solar/PW order and was disappointed install was estimated so far out already.
The new rules don't come into account until July 1, so new systems in areas that SCC fire hasn't come in and enforced new rules prematurely will pass for another 5 months or so. Also, jurisdictions can change their own rules before then at any time, and we are seeing those movements but are unpredictable as to who is next.
Right now, if Tesla releases the 9540A testing, then those separation numbers are allowed in Santa Clara County and the affected early adopters.
If July 1 comes around and Tesla hasn't finished testing and listing, then the 3' separation from each other, doors and windows will come into play at the same time all the other provisions of the new CRC R327.
This is determined by your permit status. If you have an existing valid permit to stack your Powerwalls, then that usually requires the AHJ to honor that initial agreement. So those where their installer didn't apply for the permit will be in danger. Powerwall installs are super popular, and we are 5 months out right now, I imagine its similar for many.
Permits do expire so applying for one too soon will require you to pay to extend it, but this is usually granted with any good reason.
So what is the practical impact?
80 kWh outdoors on the ground. does this mean a house cannot have more than 6 PW's ever. It did not state in one location like you have said before.
They both state the "Aggregate" rating, which I interpret as you can have them in multiple categories up to the limit.
So put 5 on the exterior wall, then 5 more on a concrete pad on the ground 10' away, if you wanted you could also have another 5 in the garage, and another 2 in the basement.
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Was not clear that is how their comments are. Would want to see this from them in writing.
Looks like another couple jurisdictions are adopting early. Woodside Fire Protection has officially adopted all the new provisions of R327, including a reasonable look at what impact protection should look like for an average home garage.
Looks like Los Altos might be doing the same as well.
Looks like Los Altos might be doing the same as well.
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Only in Woodside would the average garage contain what appears to be a Shelby Cobra and Porsche 911.
If I had to put 3 feet between my 5 PW's, they would not all have fitted. Can they be stacked? seems no if they have to be 3 feet apart. So, no more stacking?
Until Tesla releases the UL9540A testing, yes. 3' required between ESS units, no stacking, and 3' from doors and windows that lead into living spaces.
When is telsa supposed to get UL9540A? These changes would seem to have some major impact on installs?
badpirate
New Member
Seems this might be the case now in Sunnyvale, CA too 
Basically, I've got a section of wall with about 75" of usable space on a concrete pad outside the back door to my garage. Originally, I wanted to do 2 stacks of power wall (side by side with 10" from door and 5" between the units), for 3 power wall units (Couldn't do a single stack because adding a 3rd unit would edge into the city standoff between properties of 4').
They came out the other day and told me that we'd have to cut down to a single unit, because I won't be allowed to stack, and because I'll have to be 3' from the door (cutting the usable space to 39", or a single wall). Despite having earlier had the permit approved
My garage has a mini-split unit and has been given the interior treatment for a COVID office, though it has hard floor and is still listed on the final permit that I got for the work as an attached garage. I very much would love to figure out what the story is so that I can get the right new design. At the moment, I guess I'm lucky that I can get a single unit without too big of a change. Perhaps if the rules lessen, then I can stack?
Where can I find a solid source for my city, as the web seems to have nothing. @Vines - Are you aware of what makes it a living space?
Basically, I've got a section of wall with about 75" of usable space on a concrete pad outside the back door to my garage. Originally, I wanted to do 2 stacks of power wall (side by side with 10" from door and 5" between the units), for 3 power wall units (Couldn't do a single stack because adding a 3rd unit would edge into the city standoff between properties of 4').
They came out the other day and told me that we'd have to cut down to a single unit, because I won't be allowed to stack, and because I'll have to be 3' from the door (cutting the usable space to 39", or a single wall). Despite having earlier had the permit approved
My garage has a mini-split unit and has been given the interior treatment for a COVID office, though it has hard floor and is still listed on the final permit that I got for the work as an attached garage. I very much would love to figure out what the story is so that I can get the right new design. At the moment, I guess I'm lucky that I can get a single unit without too big of a change. Perhaps if the rules lessen, then I can stack?
Where can I find a solid source for my city, as the web seems to have nothing. @Vines - Are you aware of what makes it a living space?
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