Though compact, a 100-amp meter box still requires dedicated space for meters, terminals, incoming/outgoing wiring, and protective devices. The meter must be accessible for reading, inspection, and replacement, while the terminal area needs sufficient clearance for crimping, testing, and tool access.

For wall- or equipment-mounted boxes, determine whether cables enter from the top, bottom, or sides before arranging components. Inadequate bending radius, overcrowded terminations, or terminals placed too close to the door hinder installation. Ensure viewing windows align with the meter display.

Internal components should not be chosen based solely on the 100A rating. The inclusion of circuit breakers, fuses, disconnects, or ground terminals depends on the metering and distribution plan. Never sacrifice wiring and service clearance to achieve a smaller enclosure footprint.