When selecting a meter box, current rating is a key factor, but decisions should not rely solely on equipment labels or current load. System voltage, single- or three-phase configuration, estimated peak load, future expansion plans, incoming cables, outgoing circuits, and local utility metering requirements must all be verified.

100A meter boxes typically suit smaller capacities or dedicated submeter circuits; 200A boxes fit higher loads, larger conductors, or systems requiring more wiring space; 400A boxes serve higher-demand, commercial, or industrial distribution setups. Application suitability depends on actual system design rather than amp ratings alone.

Future expansion should also be planned. If current load approaches enclosure or terminal limits, adding equipment later may require replacing the entire box. Planning for extra margin, cable entry space, and terminal layouts early lowers costs and minimizes downtime.