This transparent and durable box is designed to house three-phase meters for 380V electrical systems and is equipped with 1+2 4P empty openings for convenient circuit connections. Unit 4, Bradbury Drive - Springwood Industrial Estate - Braintree - Essex - CM7 2SD - UK Three Phase Distribution Boards, Extension boxes & Metering Kit. Customer focused design for all applications and environments. Eaton Main Terminal Box, 600A, Copper, NEMA 3R, Overhead/underground, Four-wire, Three-phase, 120/208V, (2) 250-500 kcmil Eaton Selling Policy 25-000, one (1) year from the date of installation of the Product or eighteen (18) months from the date of shipment of the Product, whichever occurs first. The. 3-phase meter box, also known as a 3-phase electricity meter box, 3-phase electric meter box, three-phase meter box, or 3-phase electric box, provides a secure and compliant solution for housing 3-phase electrical meters. Our Meter Boxes are constructed from GRP making it water.