Battery Storage Room, Definition

[Seven-Delta-FortyOne]

Existing well house, with exposed Romex running from the sub panel to the lighting and pressure pump.

I don’t like it anyway, I would have used BX if I had wired it.

Owners want a solar system installed, with Lithium Ion batteries, inverter, charge controller the whole deal to run the well system.

Im going to rewire with BX, sorry MC cable, but I’m wondering if the presence of 4 batteries in the room would make it a “storage battery room”. That term is not defined in Article 100.

That would make the Romex unacceptable in the room

The other thing I’m thinking about is the fact that these requirements for battery storage rooms are mainly because of toxic fumes from lead acid batteries.

What about the sealed lithium batteries that everyone is using these days? Are we going to see a change in the rules regarding ventilation and wiring requirements, as they aren’t really necessary for some battery storage rooms?

 

[ron]

The fire code uses a threshold of 70 kWh for Lead acid or 20kWh for all types of Lithium ion type batteries, to determine when they require permits, etc. That seems like a reasonable threshold to decide of it is going to be a real amount.
I do not think there is any amount of battery threshold that would cause you to go from NM, to AC or MC cable if the occupancy is appropriate.

 

[steven765]

Trying to see the point to venting lithium ion. I'm sure the code will require it, but given the self sustaining properties of lithium-ion once thermal runaway is reached it produces it's own oxygen. Lithium produces hydrogen in the presence of water so maybe, but honestly you have far far bigger problems at that point lol.

 

[gadfly56]

The fire code uses a threshold of 70 kWh for Lead acid or 20kWh for all types of Lithium ion type batteries, to determine when they require permits, etc. That seems like a reasonable threshold to decide of it is going to be a real amount.
I do not think there is any amount of battery threshold that would cause you to go from NM, to AC or MC cable if the occupancy is appropriate.

So, if you have more than one Powerwall 2 (13.5 kW-hr), that location is a battery room? Fire code-wise.

 

[Seven-Delta-FortyOne]

[QUOTE="ron, post: 2637131,
I do not think there is any amount of battery threshold that would cause you to go from NM, to AC or MC cable if the occupancy is appropriate.
[/QUOTE]

334.12(a)7 NM Cable prohibited in battery storage rooms is the only reason why I was thinking of it.


Since the room currently has no batteries in it, if I install batteries, does that make it a battery storage room?

 

[ron]

Wow, thanks. Never realized, although never had a reason to look at NM in this application.
Good catch.
This is the definition from the International Fire Code, Chapter 2 Definitions:
[/QUOTE][/QUOTE]

 

[shortcircuit2]

So, if you have more than one Powerwall 2 (13.5 kW-hr), that location is a battery room? Fire code-wise.

Good question.

NFPA 855 in 15.7 states a maximum individual rating of 20-kwh in residential

And 15.7.1 has a table with 40-kwh aggregate inside dwelling utility room and 80-kwh in garages, accessory structures or outside.

So 3 of them 13.5 Powerwalls inside a dwelling would be .5 over

NFPA-1 has language in section 52.3.3.4 requiring a 2-hour room rating in residential? Did not look in the IFC

 

[jaggedben]

So, if you have more than one Powerwall 2 (13.5 kW-hr), that location is a battery room? Fire code-wise.

Spottily enforced, but yes. Effectively prohibits two Powerwalls inside many houses. Outdoor locations are kind of a grey area.

 

[ron]

NFPA 855 in 15.7 states a maximum individual rating of 20-kwh in residential

And 15.7.1 has a table with 40-kwh aggregate inside dwelling utility room and 80-kwh in garages, accessory structures or outside.

So 3 of them 13.5 Powerwalls inside a dwelling would be .5 over

NFPA-1 has language in section 52.3.3.4 requiring a 2-hour room rating in residential? Did not look in the IFC

Good references, but FYI, NFPA 855 is not adopted as a code by any jurisdictions that I'm aware of. NFPA 1 is only adopted by a few jurisdictions, it is mostly the IFC as the adopted Fire Code.