A modular distribution block for a high-current power system includes a ground module and one or more phase modules. The ground module includes a grounding clamp configured to electrically and mechanically connect to a DIN rail and to retain the distribution block in place with respect to the DIN rail. The phase module(s) include: a conductive splice block that connects a line current from a power supply to a powered device; and, a first surge protective device (SPD) terminal and a second SPD terminal configured to together receive and electrically connect to an SPD module, such connection forming a surge protection circuit within the distribution block, the first SPD terminal electrically connecting to the bus terminal and the second SPD terminal electrically connecting, to the splice block. A rigid bus bar electrically connects the ground module to the phase module(s).