Safety and certification: UL 9540 and UL 9540A
What the two standards evaluate, and how RAE Charge's safety architecture is designed around them.
Two standards come up in almost every conversation about stationary energy storage. They are related, but they answer different questions.
UL 9540: the whole system
UL 9540 is the safety standard for a complete energy storage system. It evaluates the battery, the power electronics, the enclosure, the controls, and the way they behave together under normal and abnormal conditions. Building codes, insurers, and interconnection processes generally expect certification to UL 9540 before a stationary storage system is installed.
UL 9540A: how a fire behaves
UL 9540A is a test method rather than a pass-or-fail certification. It characterises thermal runaway: what happens when a cell fails, whether the failure spreads to neighbouring cells, how much heat and gas is released, and how the system as a whole responds. The results feed into UL 9540 evaluation and into installation rules that govern spacing, ventilation, and placement.
How RAE Charge is designed around both
- Layered electrical protection. Integrated disconnect and fuse protection, high-current internal architecture, and coordinated power flow inside the enclosure.
- Thermal monitoring and active cooling. Thermal distribution monitoring and an active cooling system manage pack temperatures and protect long-term battery life.
- Propagation isolation. Cell-level fire and thermal propagation isolation features are part of the architecture to help limit event spread within the pack.
- Pack-level telemetry. Installers and owners can see thermal behaviour through the integrated touchscreen and through RAE Connect and RAE Summit.
What this means on site
Until certification is complete, treat placement and clearance guidance as preliminary and follow the authority having jurisdiction. Certification status and supported configurations will be confirmed in final product documentation.