Inverter Isc Input Ratings

Inverter short circuit current (Isc) rating is required to verify that the PV module string short circuit current under high irradiance does not exceed the maximum input current for the PV inverter's MPPT for compliance with NEC 690.8(A)(1)(1) and the inverter listing. Exercise caution when looking at datasheets, installation manuals and equipment labels have been reviewed by a NRTL for equipment ratings. Inverter Isc might not be reported consistently across manufacturers, if you are having trouble finding the required information on your equipment or interpreting manufacturer documentation please refer to the following examples:

For Enphase systems, the contractor may find this Enphase website helpful. First, you can enter the module brand and model number to determine eligibility with Enphase products. This tool will also show the Max Isc, based on your temperature inputs and equipment. An example, is shown below. The contractor can then enter the DC input voltage and current within SolarAPP+. In this case Max Isc is 15 A and the contractor would enter 15 A for the maximum input DC short circuit current (Isc). 

For example, the IQ7+ has a value of 20A for the max module Isc but 25 for the Maximmum input DC short-circuit current rating:

The Sunny Boy inverters have a maximum short circuit current of 18 A and “Maximum DC Voltage” of 600 V:

The Delta Mario inverters have a “Maximum System Voltage” of 600 V and max MPPT current of 15 A M4 to M8 and 25 A for the M10:

The Tesla inverter has a max MPPT current of 15 A and a maximum input voltage of 600 V:

The Fronius inverters have a maximum short circuit current of 18 A and a maximum input voltage of 800 V

Delta E6 has a “DC Max System Voltage” of 480 V and a "Maximum module short circuit current per MPPT" of 15 A.

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