Powerwall In Garage [what are the rules around this?]

[ucmndd]

This is the fundamental problem with for-profit utility monopolies. There are better ways to solve this problem. We know what they are and we know that they work. It’s just that this country is rotten to the core and we’ve apparently accepted that every single industry must be run with layers upon layers of political and private sector grifters that need to skim their share.

 

[itsc]

The fact that most (all) American utilities have trouble maintaining reliability doesn’t mean that a centralized utility has to have trouble doing so. Obviously, I have personally experienced the problems myself, so I can’t argue that central generation makes sense to consumers today in this country. I am just saying that with a reliable grid you want to put the panels in the best location to get most out of them.

 

[notsure11]

I am also in Oakland (Alameda County) in NorCal. The installers already installed two Powerwalls inside my garage months ago, but now they can't get the fire department to issue a permit (weren't they supposed to get a permit first and then install?). Apparently I need a "fire suppression system," so the installers are now asking me if I will consider an exterior wall installation.

I already have a fire sprinkler system throughout the house (it's a fairly new construction), including four sprinkler heads on the garage ceiling. There's also a smoke alarm on the garage ceiling. What else is needed to have two Powerwalls installed inside the garage here?

 

[BGbreeder]

I am also in Oakland (Alameda County) in NorCal. The installers already installed two Powerwalls inside my garage months ago, but now they can't get the fire department to issue a permit (weren't they supposed to get a permit first and then install?). Apparently I need a "fire suppression system," so the installers are now asking me if I will consider an exterior wall installation.

I already have a fire sprinkler system throughout the house (it's a fairly new construction), including four sprinkler heads on the garage ceiling. There's also a smoke alarm on the garage ceiling. What else is needed to have two Powerwalls installed inside the garage here?

I think @wwhitney and @Vines are the experts on this.

Some jurisdictions have requirements around the type of smoke (heat) alarm installed in a garage to go with ESS with requirements that it be connected to the main house alarm, but I have no idea about the City of Oakland. Have you called the city to enquire directly about what the issue(s) might be? Sometimes getting it from the source helps.

All the best,

BG

 

[ptdusn]

I am also in Oakland (Alameda County) in NorCal. The installers already installed two Powerwalls inside my garage months ago, but now they can't get the fire department to issue a permit (weren't they supposed to get a permit first and then install?). Apparently I need a "fire suppression system," so the installers are now asking me if I will consider an exterior wall installation.

I already have a fire sprinkler system throughout the house (it's a fairly new construction), including four sprinkler heads on the garage ceiling. There's also a smoke alarm on the garage ceiling. What else is needed to have two Powerwalls installed inside the garage here?

Check out the Eldie Fire Extinguishing ball. That may meet their requirements.

 

[BGbreeder]

Not that it is relevant to what the Oakland Fire is enforcing, but Tesla has a well defined protocol for fires.

https://www.tesla.com/sites/default/files/downloads/Lithium-Ion_Battery_Emergency_Response_Guide_en.pdf

 

[Vines]

I am also in Oakland (Alameda County) in NorCal. The installers already installed two Powerwalls inside my garage months ago, but now they can't get the fire department to issue a permit (weren't they supposed to get a permit first and then install?). Apparently I need a "fire suppression system," so the installers are now asking me if I will consider an exterior wall installation.

I already have a fire sprinkler system throughout the house (it's a fairly new construction), including four sprinkler heads on the garage ceiling. There's also a smoke alarm on the garage ceiling. What else is needed to have two Powerwalls installed inside the garage here?

Theoretically the (13D?) fire suppression system you have currently should be enough to satisfy the city, but your installer should communicate that to the city.

Oakland is really slow so the installer may be just punting this decision and going with an exterior solution, rather than trying to jump through the hoops of the fire department.

I would reach out (or your installer really should) to the Oakland AHJ and ask them whether the existing (13D?) fire suppression system will satisfy this requirement.

 

[notsure11]

Theoretically the (13D?) fire suppression system you have currently should be enough to satisfy the city, but your installer should communicate that to the city.

Oakland is really slow so the installer may be just punting this decision and going with an exterior solution, rather than trying to jump through the hoops of the fire department.

I would reach out (or your installer really should) to the Oakland AHJ and ask them whether the existing (13D?) fire suppression system will satisfy this requirement.

Thanks. I asked the installer what constitutes a “fire suppression system” and she had no idea what that even was! Without evening knowing what’s required to keep Powerwalls inside, she just wanted me to move Powerwalls outside.

Anyway, I told her I have four sprinkler heads in the garage and sent her a photo. She shared that with the fire department and it is now approved.

 

[Vines]

Thanks. I asked the installer what constitutes a “fire suppression system” and she had no idea what that even was! Without evening knowing what’s required to keep Powerwalls inside, she just wanted me to move Powerwalls outside.

Anyway, I told her I have four sprinkler heads in the garage and sent her a photo. She shared that with the fire department and it is now approved.

Lol, I hope their electrical knowledge is better than their fire code knowledge.

 

[holeydonut]

Lol, I hope their electrical knowledge is better than their fire code knowledge.

Damn, I can't find my diagram for the fire suppression system that ejects a flaming powerwall through the roof and onto the street.

 

[notsure11]

Lol, I hope their electrical knowledge is better than their fire code knowledge.

Unfortunately, the saga continues. As mentioned above, they already installed two Powerwalls stacked together in our garage six months ago. But the permit had expired by then and they used a different disconnect switch, so the installers submitted a revised plan for permit. Apparently, they added three 3'-4' tall bollards (3' deep) to the plan without talking to me about it. On top of that, the revised plan shows two Powerwalls side-by-side, 3' apart from each other and 3' away from Tesla Backup Gateway 2, even though that's not how they are actually installed (plus they already drilled a giant hole on the face of the back Powerwall for stacked configuration).

Regarding bollards - I don't have room for that. Besides, Powerwalls are on the side wall, out of the driving path. Thanks to this post by @Vines , I was able to convince the installers to go back to the Oakland Fire Department and get them to agree that they're unnecessary. Fingers crossed. But regarding the 3' requirement, the installers are certain that Oakland FD will not allow two Powerwalls stacked together inside the garage.

1. Does anyone know if Oakland, CA really requires two Powerwalls to be 3' apart in the garage? (I read this code requirement can be waived for batteries that have passed large-scale UL9540A fire testing, which I assume Powerwalls have, but it's up to the AHJ)

2. Is there any basis for requiring Powerwalls to be 3' away from the Tesla Backup Gateway 2?

3. They said unless Powerwalls are stacked together, they must be at least 1' above the floor. Is this true? (I'm just wary of putting so much weight on the wall).

Thank you.

 

[Vines]

Unfortunately, the saga continues. As mentioned above, they already installed two Powerwalls stacked together in our garage six months ago. But the permit had expired by then and they used a different disconnect switch, so the installers submitted a revised plan for permit. Apparently, they added three 3'-4' tall bollards (3' deep) to the plan without talking to me about it. On top of that, the revised plan shows two Powerwalls side-by-side, 3' apart from each other and 3' away from Tesla Backup Gateway 2, even though that's not how they are actually installed (plus they already drilled a giant hole on the face of the back Powerwall for stacked configuration).

Regarding bollards - I don't have room for that. Besides, Powerwalls are on the side wall, out of the driving path. Thanks to this post by @Vines , I was able to convince the installers to go back to the Oakland Fire Department and get them to agree that they're unnecessary. Fingers crossed. But regarding the 3' requirement, the installers are certain that Oakland FD will not allow two Powerwalls stacked together inside the garage.

1. Does anyone know if Oakland, CA really requires two Powerwalls to be 3' apart in the garage? (I read this code requirement can be waived for batteries that have passed large-scale UL9540A fire testing, which I assume Powerwalls have, but it's up to the AHJ)

Yes they do

2. Is there any basis for requiring Powerwalls to be 3' away from the Tesla Backup Gateway 2?

Not that I know of

3. They said unless Powerwalls are stacked together, they must be at least 1' above the floor. Is this true? (I'm just wary of putting so much weight on the wall).

Thank you.

I am not aware of this limitation from a code perspective.

 

[wwhitney]

3. They said unless Powerwalls are stacked together, they must be at least 1' above the floor. Is this true? (I'm just wary of putting so much weight on the wall).

If the weight (and moment) of a Powerwall on a 3'+ wide section of wall is an issue, your wall is trouble. In other words, barring signs of imminent wall collapse, don't worry about the weight. Being able to raise the PWs up off the floor is a feature of the non-stacked configuration, not a bug.

Cheers, Wayne

 

[Bigtanuki]

Unfortunately, the saga continues. As mentioned above, they already installed two Powerwalls stacked together in our garage six months ago. But the permit had expired by then and they used a different disconnect switch, so the installers submitted a revised plan for permit. Apparently, they added three 3'-4' tall bollards (3' deep) to the plan without talking to me about it. On top of that, the revised plan shows two Powerwalls side-by-side, 3' apart from each other and 3' away from Tesla Backup Gateway 2, even though that's not how they are actually installed (plus they already drilled a giant hole on the face of the back Powerwall for stacked configuration).

Regarding bollards - I don't have room for that. Besides, Powerwalls are on the side wall, out of the driving path. Thanks to this post by @Vines , I was able to convince the installers to go back to the Oakland Fire Department and get them to agree that they're unnecessary. Fingers crossed. But regarding the 3' requirement, the installers are certain that Oakland FD will not allow two Powerwalls stacked together inside the garage.

1. Does anyone know if Oakland, CA really requires two Powerwalls to be 3' apart in the garage? (I read this code requirement can be waived for batteries that have passed large-scale UL9540A fire testing, which I assume Powerwalls have, but it's up to the AHJ)

2. Is there any basis for requiring Powerwalls to be 3' away from the Tesla Backup Gateway 2?

3. They said unless Powerwalls are stacked together, they must be at least 1' above the floor. Is this true? (I'm just wary of putting so much weight on the wall).

Thank you.

Stacked units don't load the wall. They actually all sit on the floor and are held together with a stacking bracket. The main load on the wall would be seismic. I have 3 stacked in my garage under the remote main breaker panel.

 

[Redhill_qik]

If the weight (and moment) of a Powerwall on a 3'+ wide section of wall is an issue, your wall is trouble. In other words, barring signs of imminent wall collapse, don't worry about the weight. Being able to raise the PWs up off the floor is a feature of the non-stacked configuration, not a bug.

Cheers, Wayne

According to the Powerwall 2 data sheet it is only 114 kg or 251.3 lbs. Not that much at all.

 

[charlesj]

According to the Powerwall 2 data sheet it is only 114 kg or 251.3 lbs. Not that much at all.

Right. You power lift that regularly.

 

[Redhill_qik]

Right. You power lift that regularly.

Well when I was much younger yes, right now nope. In the architectural sense, I don't think that is a lot of dead to handle between two 2x4s. I thought it was a lot more in the 500-1,000lb range.

 

[charlesj]

Well when I was much younger yes, right now nope. In the architectural sense, I don't think that is a lot of dead to handle between two 2x4s. I thought it was a lot more in the 500-1,000lb range.

Yep, it is nothing for a pair of 2x4s.

 

[holeydonut]

Well when I was much younger yes, right now nope. In the architectural sense, I don't think that is a lot of dead to handle between two 2x4s. I thought it was a lot more in the 500-1,000lb range.

Nowadays @Redhill_qik gets his workout lifting the PG&E black and white NEM2-PS bill and sorting through all the pages.

 

[wwhitney]

If the weight (and moment) of a Powerwall

So, a stud grade hem-fir 2x4 has a maximum bending moment capacity of ~170 ft-lbs if a random online calculator is to be believed (i.e. with a grain of salt). A single Powerwall is about 6" thick and weighs about 250 lbs, so if you allow for it to be 1" off the face of the stud itself, you get a moment arm of 4", and a moment of ~63 lbs. Not a problem when you have 2 studs with a combined moment capacity of 340 ft-lbs.

But this analysis also shows why you don't stack PWs when hung on the wall. Stacking two would give you 500 lbs about ~7" off the face of the stud (center of mass), which gives you a moment of 290 ft-lbs. Still less than the combined moment capacity of 340 ft-lbs for the two studs, but not much margin of error. Add in some lateral loading from wind or seismic, and the two studs would be over capacity.

Cheers, Wayne