Energy storage cabinet installation distance

How far should ESS units be separated from each other?

In Section 15.5 of NFPA 855, we learn that individual ESS units shall be separated from each other by a minimum of three feet, unless smaller separation distances are documented to be adequate and approved by the authority having jurisdiction (AHJ) based on large-scale fire testing.

How far apart should storage units be positioned?

Therefore, if you install multiple storage units, you have to space them three feet apart unless the manufacturer has already done large-scale fire testing and can prove closer spacing will not cause fire to propagate between adjacent units.

How much energy can a ESS unit store?

Individual ESS units shall have a maximum stored energy of 20 kWh per NFPA Section 15.7. NFPA 855 clearly tells us each unit can be up to 20 kWh, but how much overall storage can you put in your installation? That depends on where you put it and is defined in Section 15.7.1 of NFPA 855.

How many ESS units can be installed on a wall?

The diagram shows that each ESS unit can have a maximum rating of 20 kWh, and if you’re going to install two units, let's say outside on your wall, you need to have the appropriate spacing between those units and three-feet separation from doors and windows per NFPA 855 15.6.1.

What is a battery energy storage system?

Battery energy storage systems (BESS) stabilize the electrical grid, ensuring a steady flow of power to homes and businesses regardless of fluctuations from varied energy sources or other disruptions. However, fires at some BESS installations have caused concern in communities considering BESS as a method to support their grids.

How many kWh can a house use?

The diagram also shows that if you're inside the home, you can go up to 40 kWh; if you’re outside the home on the wall, you can go up to 80 kWh; and if you're in a garage, you could also have 80 kWh there. All locations will require multiple units to reach the 40/80 kWh limit, which is fine as long as they're adequately spaced per this code.