EX three phase low voltage dry type distribution transformers from Square D comply with DOE energy conservation standards and Natural Resources Canada (NRCan) minimum energy efficiency levels. This transformer is a 300kVA, 480V primary (three wire), 480Y/277V secondary (four wire) with aluminum windings with a 220 insulation system design for 150 degree C temperature rise. This transformer’s DOE 2016 and NRCan efficiency is a minimum of 99.02% at 35% loading and 75°C temperature. Terminals are designed to accommodate wire ranges sized for 125% of the secondary nameplate current and 250% of the primary nameplate current. The terminals allow for NEMA two hole lugs and wiring bending radius to align with the wire ranges and to allow for side and bottom access. Units are natural air cooled with exhaust vents located on the front only, allowing the transformers to be mounted with rear clearance to obstructions of ½ inch. Units are shipped as Type 1 for indoor installation, field convertible to Type 2 via dripshield for indoor applications with dropping water or to Type 3R via weathershield for outdoor installation. The transformer's open bottom design limits the units to floor mounting. EX transformers have a low sound level, with a minimum of 3dB below NEMA Standard ST-20 requirements. Units are specifically designed to function with other Square D equipment; inrush is coordinated to meet identified breaker trip curves, and IZ levels allow for let through current to match AIR levels of panelboards. See product data sheets for these values.