Battery ground clearance ( inside garage)

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MSI

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Sr PV Design Engineer
According to Article 2018 IRC M1307.3, appliances that could ignite vapors must be positioned at least 18 inches off the garage floor. Does this mean that all batteries, such as those from Tesla and Solaredge, must also be placed 18 inches above the ground? If we cannot place the batteries at this height, should a platform be added to achieve the required clearance?
 
MSI said:
According to Article 2018 IRC M1307.3, appliances that could ignite vapors must be positioned at least 18 inches off the garage floor. Does this mean that all batteries, such as those from Tesla and Solaredge, must also be placed 18 inches above the ground? ...
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No, generally speaking. These energy storage systems don't meet the definition of an ignition source in that code just by being electrical. If the ESS had an integral breaker or switch that would end up less than 18" from the floor then that could count, but ordinarily they don't. I've never run into this being a problem for energy storage installations.
 
hbiss said:
I would want to know how you would build a platform in a garage for a Tesla...
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Tire ramps. And hopefully some sort of "STOP NOW!!!!" mechanism so you don't go too far and drive off the ends of the ramps like a certain teenager did while in a rush to change the oil thirty-odd years ago :sweatdrop:
 
MSI said:
According to Article 2018 IRC M1307.3, appliances that could ignite vapors must be positioned at least 18 inches off the garage floor. Does this mean that all batteries, such as those from Tesla and Solaredge, must also be placed 18 inches above the ground? If we cannot place the batteries at this height, should a platform be added to achieve the required clearance?
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I've yet to see a Powerwall that would not fit at such an elevation. And yet to see a garage that didn't have head room that couldn't be stood up within so technically plenty of room for elevation of the Powerwall.
Under normal operation there would not be any sparking components for a Powerwall, but in the event of a fault or failure there is that potential so the minimum height would be adhered to.

Perhaps getting the dimensions of the proposed equipment might clear up this concern.

AFA a platform, what do you want to elevate to need a platform?
 
Fred B said:
I've yet to see a Powerwall that would not fit at such an elevation. And yet to see a garage that didn't have head room that couldn't be stood up within so technically plenty of room for elevation of the Powerwall.
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Powerwalls have provisions for floor mounting so it's partly a question if those provisions would be allowed in a garage, but also the discussion extends beyond that brand. Some ESS (such as Enphase) have dimensions that allow for two rows of equipment on a wall but the height of a typical garage wall may be a constraint to where you need to put the lower row within 18" of the floor. I've done exactly that many times.

Under normal operation there would not be any sparking components for a Powerwall, but in the event of a fault or failure there is that potential so the minimum height would be adhered to.
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The definition of ignition source in the mechanical code is:
"IGNITION SOURCE. A flame, spark or hot surface capable of igniting flammable vapors or fumes. Such sources include appliance burners,
burner ignitors and electrical switching devices."

To me that would apply to circuit breakers, switches, and receptacles where there might be a spark under normal operation, but not to wiring or equipment that would not normally be expected to produce such things. The point here is to prevent normally expected flame, spark or heat, from igniting vapors that might be in a garage (from a gasoline spill? I don't know what other low lying vapors they are specifically worried about.) I don't think the requirement should be extended to all items that could theoretically catch fire, or all items that are electrically energized, but which are not supposed to produce flame, spark or meaningful heat under normal operations. If a Powerwall catches fire that is its own problem; it's not a spark or flame that would otherwise be okay outside of the presence of vapors. So I strongly disagree with you on this statement, for the general case. Most lithium battery ESS have environmentally enclosed cell packs and would not necessarily produce external spark or flame for every internal fault. Some have integral switches or circuit breakers, so I would apply the rule to those components when present. But as long as the switch or circuit breaker is above 18" I would consider the requirement adhered to even if other parts of the ESS were below 18".

AFA a platform, what do you want to elevate to need a platform?
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He was asking if elevating the equipment using a floor mount option would comply with the 18" requirement, if that applied. A platform would comply, in my opinion. (Probably rarely would it be the best option; with ESS that have wall mount options it would probably be easier to go that route. But you could do it if you wanted to.)
 
jaggedben said:
electrical switching devices.
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Presumably that doesn't include solid state devices.

So I guess the question for something like Tesla Powerwall would be whether the enclosure has any vents or openings less than 18" above the bottom of the unit, and then if it does, whether it has any contactors or other electrical switching devices also less than 18" above the bottom unit.

I understand Powerwall 3 is designed to be flood resistant for up to 600 mm, so I expect that means it has no vents or openings less than 600 mm (~24") above the bottom. Not sure about Powerwall 2, although I expect that one has been discontinued?

Probably all a non-issue, but still worth confirming.

Cheers, Wayne
 
Does the powerwall suck in air from the bottom to cool the internals?

I don't know how accurate the image is below. I would mount it above 18" to be safe and move on. As Wayne mentioned, you wouldn't want the guys who come through cleaning the garage with water and soap soaking it either. That might not do anything with water "resistance" but long term it can wear away the paint and start rusting stuff.



1738258979673.png
 
This is the language of the residential code requirement.

Appliances having an ignition source shall be elevated such that the source of ignition is not less than 18 inches (457 mm) above the floor in garages.
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You guys are gonna have to convince me why the 18" would apply to vents when the language simply says the source of ignition.

Also even on ESS that have vents for active cooling there's typically going to be many layers of material between the airflow sections and the actual cells, i.e. still nothing normal that could ignite vapors.
 
So we can't have ICE cars in our garages...the normal operating temperature of the catalytic converter is 500 to 800 degrees F and the auto ignition temperature for gasoline is around 550 F. (note am calling the car an appliance here :) )
 
jaggedben said:
This is the language of the residential code requirement.



You guys are gonna have to convince me why the 18" would apply to vents when the language simply says the source of ignition.

Also even on ESS that have vents for active cooling there's typically going to be many layers of material between the airflow sections and the actual cells, i.e. still nothing normal that could ignite vapors.
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oil-based paint, paint thinners, alcohol (even in windshield washer fluid if stored in large enough quantities), gasoline, etc. vapors are almost all heavier than air - that is where the 18 inches AFF comes from, the code is trying to prevent ignition sources from a zone where those vapors might be. if an air intake sucks up those flammable vapors / gasses, the moving air may dilute them adequately so that they are no longer flammable / explosive, but i wouldn't want to take that gamble in my garage. i know we can't change the way the Power Wall is manufactured, but it almost seems like it would be better if the fans were at the top but drew ventilating air IN at the top and drove it OUT at the bottom.
 
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