Powerwall install location

[esquid2]

Hello-

I have a single powerwall getting installed soon and want to know if either Tesla or NEC/California building code would disallow putting the powerwall in an unfinished basement/dug-out crawl space on concrete slab where there's only 5'10" working height below the floor joists. Ideally along exterior wall at base of foundation. No sheetrock ceiling currently. The slab is about 12" below grade (typical craftsman style cripple wall) and no issues with water egress. Climate is very moderate.

Thanks.

 

[bayareaever]

I have three PWs in an unfinished basement recently installed a few cities to your north but in Contra Costa County. They are stacked against the concrete foundation and sitting on a concrete slab which is below grade. I have no water intrusion issues either and my installer (Tesla) didn’t seem to be even the slightest bit concerned about putting them below grade.

The big difference for mine is vertical clearance which is closer to ~7’ under the floor joists. I was told PW+ Is too tall for the space but I didn’t care much about getting the PW2s anyway. I think vertical clearance would be an issue for you but I’m certainly no expert.

Luckily my space was workable because I had absolutely no alternative location and no one from Tesla bothered to scrutinize it much before install was imminent. My advice is to either have a back-up location or else make sure the installer is aware of your planned location in detail well in advance of install.

 

[BGbreeder]

You might want to look over here in a post by @Vines.
Enclosure required for Powerwall in MA

All the best,

BG

 

[DrSmile]

My Powerwalls are hanging on the walls well off the floor in my utility room because I had water flooding concerns. Tesla said there was no actual need to hang them up but agreed to do so. They are not stacked which might be an issue if you have a lot of them.

 

[Vines]

Hello-

I have a single powerwall getting installed soon and want to know if either Tesla or NEC/California building code would disallow putting the powerwall in an unfinished basement/dug-out crawl space on concrete slab where there's only 5'10" working height below the floor joists. Ideally along exterior wall at base of foundation. No sheetrock ceiling currently. The slab is about 12" below grade (typical craftsman style cripple wall) and no issues with water egress. Climate is very moderate.

Thanks.

Besides the working space issue, the basement will need to be finished with 5/8" Type X sheetrock.

I would expect both Tesla, and Oakland AHJ to push back. They are very specific about their ESS requirements, and with a 2-3 month wait for a permit among the slowest jurisdictions around.

 

[esquid2]

Thanks all for replies!

@bayareaever -
Yeah definitely Powerwall+ won't fit, in this case it's just a single powerwall2, which seems to only need 45" + 2" vertical clearance above (I'd still have nearly 2'). Mostly wondering as there may be a working headroom type requirement.

@BGbreeder / @Vines -
Thanks, yeah fire requirement is annoying for sure. If my understanding is correct, I thought with just one Powerwall 2 it may not apply in California (I saw only for systems > 20kWH)? But if that 5/8 sheetrock is a requirement yes it will be annoying to comply with it in any of the indoor space! Especially as it seems like they handle pretty impressively in the case of fires & cell failures.

We have the permit issued now, so might call them up and see if the inspector can answer some of these questions. Unfortunately even though getting installed by Tesla, they've been pretty hard to get straight answers from on some of these items.

 

[Vines]

Thanks all for replies!

@bayareaever -
Yeah definitely Powerwall+ won't fit, in this case it's just a single powerwall2, which seems to only need 45" + 2" vertical clearance above (I'd still have nearly 2'). Mostly wondering as there may be a working headroom type requirement.

@BGbreeder / @Vines -
Thanks, yeah fire requirement is annoying for sure. If my understanding is correct, I thought with just one Powerwall 2 it may not apply in California (I saw only for systems > 20kWH)? But if that 5/8 sheetrock is a requirement yes it will be annoying to comply with it in any of the indoor space! Especially as it seems like they handle pretty impressively in the case of fires & cell failures.

We have the permit issued now, so might call them up and see if the inspector can answer some of these questions. Unfortunately even though getting installed by Tesla, they've been pretty hard to get straight answers from on some of these items.

The working space required is 6'6" you might get away with 5'10" or you might not.

The threshold as of July 1 is 1 kWh. Any more storage than that requires a permit.

 

[esquid2]

Found the other thread where I'm basing most of my info wrt CA fire requirements:

New Cal fire code for Powerwalls?

Has anyone hit the new fire code requirements when designing or permitting a Powerwall in CA. The new rules seem pretty onerous, especially the one about the powerwalls needing to be, er, 3 feet from any wall: Challenges for batteries in the California fire code

teslamotorsclub.com

@Vines -
Is the working space requirement you're referring to the general one from NEC or something else? For Section 110.26(a)(3)(e) if I understand it right its for panels and service equipment only?

WRT "requiring a permit", yes we're definitely doing permits.

 

[jjrandorin]

Found the other thread where I'm basing most of my info wrt CA fire requirements:

New Cal fire code for Powerwalls?

Has anyone hit the new fire code requirements when designing or permitting a Powerwall in CA. The new rules seem pretty onerous, especially the one about the powerwalls needing to be, er, 3 feet from any wall: Challenges for batteries in the California fire code

teslamotorsclub.com

@Vines -
Is the working space requirement you're referring to the general one from NEC or something else? For Section 110.26(a)(3)(e) if I understand it right its for panels and service equipment only?

WRT "requiring a permit", yes we're definitely doing permits.

Since you are a new member here and wouldnt know, I will let you know that @Vines is not "just another member". He is someone who works in the solar industry, designing PV + ESS systems, in Northern California (not for Tesla Energy though).

I mention that because I think its important to know that his statements are not "guesses" they are usually statements from his interactions with various AHJs (authority having jurisdictions). In general, he is not guessing, when he makes a statement like the one in post #5.

 

[holeydonut]

The threshold as of July 1 is 1 kWh. Any more storage than that requires a permit.

The heck... a 100 amp hour 12V car battery is 1.2 kWh. Are they saying if you plug your car into a trickle charger then it needs to be permitted? Maybe the solution is to drill weep holes on the bottom of the car battery...

(yes this is sarcasm... I can picture wwhitney saying something about the cord and plug rule or some numbers and stuff).

 

[Vines]

Found the other thread where I'm basing most of my info wrt CA fire requirements:

New Cal fire code for Powerwalls?

Has anyone hit the new fire code requirements when designing or permitting a Powerwall in CA. The new rules seem pretty onerous, especially the one about the powerwalls needing to be, er, 3 feet from any wall: Challenges for batteries in the California fire code

teslamotorsclub.com

@Vines -
Is the working space requirement you're referring to the general one from NEC or something else? For Section 110.26(a)(3)(e) if I understand it right its for panels and service equipment only?

WRT "requiring a permit", yes we're definitely doing permits.

I am speaking of a general NEC requirement 110.26. The answer to your question depends on the AHJ. In my opinion the PW switch on the side means it is likely to need someone to operate it while energized. This switch is needed to commission the system, change the settings or reset the system.

I am curious to hear others opinions on this item, since technically a stack of 3 powerwalls violates working clearance for the rear most unit.

 

[esquid2]

Since you are a new member here and wouldnt know, I will let you know that @Vines is not "just another member". He is someone who works in the solar industry, designing PV + ESS systems, in Northern California (not for Tesla

Since you are a new member here and wouldnt know, I will let you know that @Vines is not "just another member". He is someone who works in the solar industry, designing PV + ESS systems, in Northern California (not for Tesla Energy though).

I mention that because I think its important to know that his statements are not "guesses" they are usually statements from his interactions with various AHJs (authority having jurisdictions). In general, he is not guessing, when he makes a statement like the one in post #5.

Energy though).

I mention that because I think its important to know that his statements are not "guesses" they are usually statements from his interactions with various AHJs (authority having jurisdictions). In general, he is not guessing, when he makes a statement like the one in post #5.

Thanks for the reply and info. Sorry if I offended anyone--I never meant to imply that Vines' posts were guesses or that he wasn't highly qualified. If anything, I only meant to make sure all posters were given more context on my setup (that it's only 1 powerwall which may affect requirements and perhaps that codes in my area are different from where others maybe had experience) in order to get the best advise. I truly appreciate help from everyone on this forum!

 

[jjrandorin]

Thanks for the reply and info. Sorry if I offended anyone--I never meant to imply that Vines' posts were guesses or that he wasn't highly qualified. If anything, I only meant to make sure all posters were given more context on my setup (that it's only 1 powerwall which may affect requirements and perhaps that codes in my area are different from where others maybe had experience) in order to get the best advise. I truly appreciate help from everyone on this forum!

Intent is hard to read sometimes, but no apology needed. Your posts didnt seem offensive or anything, sorry for giving you that impression, and that certainly wasnt my intention.

Good luck with your upcoming project!

 

[Vines]

Thanks for the reply and info. Sorry if I offended anyone--I never meant to imply that Vines' posts were guesses or that he wasn't highly qualified. If anything, I only meant to make sure all posters were given more context on my setup (that it's only 1 powerwall which may affect requirements and perhaps that codes in my area are different from where others maybe had experience) in order to get the best advise. I truly appreciate help from everyone on this forum!

I didn't read it that way either, so no offense taken.

For permits before July 1 , the 20 kWh was a threshold where a permit was required. If you have an existing permit issued before July 1 you may be ok.

Likely if a permit was issued, then Oakland would have made it very clear what restrictions were on the installation with redline or plan check comments.

 

[esquid2]

To satisfy the new CRC fire requirements for the Powerwall we may end up building a small closet/partition wall around it--as the unfinished basement space it will be in is quite large. I'm mostly trying to figure out how large such a closet/room would need to be to be acceptable (e.g. could we get away with something like 6-18" clearance in front before door if we had sufficient room on sides?).

 

[miimura]

To satisfy the new CRC fire requirements for the Powerwall we may end up building a small closet/partition wall around it--as the unfinished basement space it will be in is quite large. I'm mostly trying to figure out how large such a closet/room would need to be to be acceptable (e.g. could we get away with something like 6-18" clearance in front before door if we had sufficient room on sides?).

If the 5/8" drywall around the PW is a hard requirement by the AHJ, I think your "closet" idea is a good one. Framing in a couple short walls and putting 5/8" drywall all around the inside facing the PW and installing a fire rated door seems like a lower cost solution than drywalling the entire space. What ventilation will be allowed is also something to look into.

 

[holeydonut]

I'm confused, how is installing a Powerwall surrounded by drywall safer than... basically whatever was happening before? I can't imagine that a fire rated door and drywall are the type of materials that can keep a thermal runaway lithium ion battery in check.

 

[KHYE]

Good timing. I'm in the process of ordering the system + 1 PW+ with Tesla. After site survey, even after showing their guy with multiple potential locations, they came back with installing in the garage option (which is 20+ ft away from main service panel). We might want to convert the garage into living space and with PW, this is not possible.

One of my preferred locations is my crawlspace. I have a big and high crawlspace and a big concrete pad where the old furnace used to be. Anyway, I sent them my 4 other locations and see what they will say. I haven't accepted my design due to this.

 

[miimura]

I'm confused, how is installing a Powerwall surrounded by drywall safer than... basically whatever was happening before? I can't imagine that a fire rated door and drywall are the type of materials that can keep a thermal runaway lithium ion battery in check.

It's just the standard code for separating an area like a garage that could contain combustibles from a living space.
Personally, I find a lot of the new regulations regarding batteries to be very poorly formulated.

 

[sunwarriors]

I wonder if this blanket can starve a powerwall fire and it eventually goes out if left on for hours.