The paper presents a model of a single phase-to-ground fault (SPGF) implemented in the MATLAB Simulink software. This fault type is the most common for distribution networks with isolated, compensated or resistance grounded neutral. There is intermittent arc fault which is especially typical for cable lines. The latter is a challenging issue not only for protection but also for simulation. The developed block allows modeling of intermittent arc faults. Arc faults are implemented in accordance with Petersen theory or Peters and Slepian theory. It is possible to select one of the arc ignition voltage settings such as specified constant, linear signal, time-stepping signal, and their combination. Besides, the block has various possibilities of random arc interruption in the manner of pulse generator, white noise, switching pattern. The developed block provides wide configuration options. Inner structure of the model is described in detail. The block operation with different settings is shown for simple test scheme of distribution network with two feeders. Developed SPGF block is freeware. © 2023 IEEE.