1. An inverter device having an inverter module for converting direct current (DC) power into alternate current (AC) power and supplying the AC power to a load, the device including:a casing housing the inverter module therein and having a plurality of heat dissipation holes defined in a rear face thereof;
an input/output terminal unit fastened to a top of a front face of the casing using first fasteners, wherein a plurality of cables are electrically coupled to an inner face of the input/output terminal unit using second fasteners; and
a heat dissipation fan disposed below the input/output terminal unit and fixed to the front face of the casing, wherein the fan discharges heat generated from the inverter module to an outside of the casing through the heat dissipation holes,
wherein the input/output terminal unit is open at a front and a top thereof, wherein the input/output terminal unit includes a plurality of terminal blocks, each of the terminal blocks having a slot formed therein,
wherein the terminal blocks are arranged horizontally and are individually fastened to the casing.