A modular switch box typically refers to a housing or enclosure that contains modular switches. In electrical switches for homes or offices, "modular" usually means that the switches are designed to be easily combined or customized in different configurations within the same box or plate.
A Surge Protective Device (SPD) is precisely engineered to safeguard electrical systems and appliances from surge incidents. It accomplishes this by curbing transient voltages and redirecting surge currents. Surges can emanate from both external and internal sources.