Navigate Rapid Shutdown with Fronius and IronRidge

Commercial rapid shutdown without MLPE

2020 NEC 690.12 Rapid Shutdown of PV Systems on Buildings requires that all PV arrays installed on buildings shall include rapid shutdown functions to reduce shock hazard for Fire Fighters.

System designers and installers must comply with rapid shutdown requirements in accordance with NEC 690.12 as one method to control the conductor limits within the PV array boundary. This compliance can be met with the use of various module level rapid shutdown devices. However, this only adds to the cost and complexity of the system and installation, as well as possible safety and reliability risks due to significant increase in component count.

What's the solution?

UL 3741 provides an alternative to rapid shutdown requirements without the use of MLPE. Under this standard, string inverters, certified in combination with a tested mounting and wire management system, and installed under specific PV array guidelines, can also be used as a shock hazard control system.

For more specifics, see link to our UL 3741 page here.

Fronius Symo Advanced

The Fronius Symo Advanced is the ideal compact three-phase inverter for commercial and industrial applications. This inverter combines the benefits of a modern string inverter, such as the Dynamic Peak Manager for shade mitigation and an integrated Power Line Communications (PLC) transmitter for SunSpec Rapid Shutdown.

However, when installed within one foot of the array boundary in conjunction with the IronRidge BX Ballasted System, the Symo Advanced is UL 3741 certified and can be used in rapid shutdown applications without additional components.

Fronius Symo Advanced

Output classes 10 to 24 kW
Ideal for commercial applications
Integrated PLC transmitter (SunSpec Rapid Shutdown as standard)
Available for all system voltages from 208 to 240 volts
Models with 15 to 24 kW operate with 480-volt WYE grids

UL 3741 Certified Power Classes

Fronius Symo Advanced 10.0-3 208-240/Lite
Fronius Symo Advanced 12.0-3 208-240/Lite
Fronius Symo Advanced 15.0-3 480/Lite
Fronius Symo Advanced 20.0-3 480/Lite
Fronius Symo Advanced 22.7-3 480/Lite
Fronius Symo Advanced 24.0-3 480/Lite

IronRidge® BX

Delivers superior power density and design flexibility to flat roof solar arrays.
Made of a glass reinforced composite, the BX Chassis is engineered for extreme structural loading, yet is also shaped to be roof-friendly and easy to install.
Combined with wire management components to safely route wiring under modules and through raceway channels makes this system perfect for UL 3741 applications.