Received an Error Message: R559 or R659 Module Short Circuit Current and RSD or Inverter

Error Message Received:

Typical Causation:

This error is usually caused by pairing either a rapid shutdown device (RSD) or an inverter with a solar module that exceeds the device's specified electrical input. Often, the issue arises when the solar module’s output, combined with high-temperature corrections, becomes too large for the device to handle.

The calculation for this section is the solar module's short circuit current at standard test conditions (ISC) multiplied by 1.25 (NEC Article 690.8). If the dropdown input for "is the solar module bifacial was answered "yes", there is an additional multiplier of 1.3. Therefore, the equation(s) look like this:

ISC x 1.25 = non-bifacial solar modules

ISC x 1.25 x 1.3 = bifacial solar modules

If the total number is greater than the device's PV input, you'll receive one of the above errors.

An Example:

Consider the following example with the Tesla MCI-2 RSD and a solar module that has an excessively high wattage output:

Explanation

In this case, the error occurred because the solar module’s output was 17.15 amps after applying a high-temperature correction. The selected MCI-2 RSD has a maximum input capacity of 17 amps.

Potential Solution

As a solution, a different solar module or rapid shutdown device (RSD) pairing can be utilized, such as the MCI-1, and the SolarAPP+ inputs to be adjusted accordingly.

To resolve the issue, a solar module with a lower output should be utilized or switch to an MCI-1 RSD, which supports inputs up to 19 amps.