New CEI 0-21 requirements for SOLIVIA TR transformer-based series inverters installed in Italy

As of January 1, 2013, the CEI 0-21 standard has set forth new requirements for inverters operating on the Italian grid.

In the past, it was only needed for the manufacturer to give a self-declaration for CEI 0-21 compliance. Now it is required, that an official certificate issued by a third party, certifying compliance to CEI 0-21 be given. Delta offers the appropriate certificates for download on our web site.

Further, the TR series inverters, 2.5 TR, 3.0 TR, 3.3 TR, and 3.6 TR, in PV plants less than 6 kW, will require a new USB/I card (with digital inputs) to be installed to meet the ENEL monitoring and disconnection requirements of CEI 0-21. A cable connector kit is also required that when installed allows IP65 protection in outdoor installations.

For plants > 6 kW, the CEI 0-21 requires that an external SPI (system protection interface) be provided.

The 5.0 TR inverter is still in approval process to meet the new CEI 0-21 requirement and we will notify you when it is ready in a future communication.

Detailed information about the USB/I card and cable connector requirement for TR inverters installed in Italy is offered on our web site at: or via the Delta technical support team at: 800 787 920 (free call in Italy).

The 15 TL, 20 TL and 30 TL transformerless inverters are already certified to meet the CEI 0-21 requirement for low voltage connected grids without any special requirements. The CEI 0-21 certificate and self-declaration document for these models can be found on the Delta website at