Fronius Primo

Power generation that lasts.

With power categories ranging from 3.8 kW to 15.0 kW, the transformerless Fronius Primo is the ideal compact single-phase inverter for residential applications. The sleek design is equipped with the SnapINverter hinge mounting system which allows for lightweight, secure and convenient installation. The Fronius Primo has several integrated features that set it apart from competitors including dual powerpoint trackers, high system voltage, a wide input voltage range, Wi-Fi* and SunSpec Modbus interface, and Fronius’ online and mobile monitoring platform Fronius Solar.web. The Fronius Primo also works seamlessly with the Fronius Rapid Shutdown Box for a reliable NEC 2014 690.12 and NEC 2017 690.12(B)(1) solution.
Please choose your desired product.

Product details


Number of MPPT2
Recommended PV Power (kWp)4,0 - 7,8 kWp
Max. usable input current18,0 / 18,0 A
Max. usable input current total (MPPT1 + MPPT2)
36 A
Max. array short circuit current (1.5 * Imax)
27 / 27 A
Nominal input voltage
420 V
Operating voltage range
80 - 600 V
MPP Voltage Range
240 - 480 V
Max. input voltage
600 V (1000 V optional*)


Max. output power 240 V5000 VA
Max. output power 208 V5000 VA
Output configuration
1~ NPE 208 / 240 V
Frequency range45 - 66 Hz
Nominal operating frequency60 Hz
Total harmonic distortion< 5 % 5="" %="">
Power factor range
0,85 - 1 ind./cap.
Max. continuous output current 240 V20,8 A
Max. continuous output current 208 V24,0 A
OCPD/AC breaker size 240 V30 A
OCPD/AC breaker size 208 V30 A
Max. efficiency96,9 %
CEC efficiency 240 V95,5 %
CEC efficiency 208 V95,5 %


Dimension (width)1,41 ft
Dimension (height)2,06 ft
Dimension (depth)8,11 in
Weight47,41 lbs
Protection classNEMA 4X
Night time consumption< 1 w 1="">
Inverter topologyTransformerless
CoolingVariable speed fan
Elevation4000 m (13120 ft) with a max. input voltage of 1000 V
Certificates and compliance with standardsUL 1741-2010 Second Edition (incl. UL1741 Supplement SA 2016-09 for California Rule 21 and Hawaiian Electric Code Rule 14H), UL1998 (for functions: AFCI, RCMU and isolation monitoring), IEEE 1547-2003, IEEE 1547.1-2003, ANSI/IEEE C62.41, FCC Part 15 A & B, NEC 2017 Article 690, C22. 2 No. 107.1-16, UL1699B Issue 2 -2013, CSA TIL M-07 Issue 1 – 2013
DC connection terminals4x DC+ and 4x DC- screw terminals for copper (solid/stranded/fine stranded) or aluminium (solid/stranded)
AC connection terminalsScrew terminals 12 - 6 AWG
Revenue Grade MeteringOptional (ANSI C12.1 accuracy)


DC reverse polarity protection
Anti islanding
internal; in accordance with UL 1741-2016-09, IEEE 1547-2003 and NEC 2017
Over temperature protection
Output power derating / Active cooling
Rapid shutdown compliant
Yes (according to NEC 2014)
Ground fault protection with isolation monitor interrupter
DC disconnect


Wi-Fi / Ethernet LANWireless standard 802.1 1 b/g/n / Fronius Solar.web, SunSpec Modbus TCP, JSON
USB (A socket)Datalogging and inverter update possible via USB
2x RS422 (RJ45 socket)Fronius Solar Net
Datalogger and webserverIncluded
Serial RS485SunSpec Modbus RTU
6 inputs and 4 digital I/OsLoad management; signaling, multipurpose I/O

SnapINverter technology

The Fronius SnapINverter generation features a simple, standardized hinged mounting system that makes installation and service easier than ever. The inverters consist of two main parts: the power stage and the connection compartment, ensuring a convenient installation process. First, you mount the remarkably lightweight connection compartment and all wiring to the wall. Then simply snap the power stage in - allowing for installation within 15 minutes by only 1 person! Furthermore, installers don’t need to remove the entire inverter for servicing. Just take the power stage and leave all wires in place, making the Fronius SnapINverters the most user-friendly inverters on the market.

Integrated data communication

Fronius believes that every solar system should be monitored. Therefore, we offer integrated data communication capabilities for all our inverters and free online monitoring with Fronius Solar.web. Simply connect the inverter to the internet via Wi-Fi and use our Modbus TCP SunSpec, Modbus RTU SunSpec or Fronius Solar API (JSON) interface for seamless data communication to third parties. The different interfaces can be operated in parallel to the Fronius Solar.web online platform. The monitoring is easily set up via our smartphone app - it's so easy, even the home owner can do it.

Design Flexibility

Fronius inverters offer great design flexibility, giving you all the options you need and making system design extremely simple. Two independent MPP trackers, wide DC input voltage windows and oversizing of up to 150% make the inverters suitable for complex roofs, different array sizes and multiple orientations. The Fronius Design Flexibility offers a solution for all your system design needs

Smart Grid Ready

Fronius inverters enable the grid of tomorrow. Our inverters are already equipped to meet the technical requirements of a smart grid of the future. A set of smart functions, known as Advanced Grid Features, are built into the inverters. They include a wide range of control functions for dynamic feed-in of both effective and reactive power. These functions are designed to enable a stable grid and highest solar density, while preventing unwanted system shutdowns if grid parameters exceed their thresholds.

Arc Fault Circuit Interruption Integrated

The Fronius Arc Fault Circuit Interruption (AFCI) makes each inverter NEC 2011 compliant and offers a best-in-class solution for detecting arcs. Ensuring the utmost safety, AFCI shuts down the inverter in the event of an arc fault within your solar system.

Active Cooling

Active cooling technology relies on one or more fans, which not only avoid hot spots, but also regulate the air circulation inside the inverter, thus keeping the temperature of the power electronics low. This has a positive effect on the service life of the devices, optimises yields and reduces costs. At Fronius, active cooling is supplied as standard in all devices.