In short, if you need to know the per-phase current in a three-phase system, then add the total wattage of the loads, multiply by 1.73 and divide by 3. These loads are often referred to as “delta connected” because of the triangle, or delta, formed by connecting them across two phases. Don’t forget to account for the additional power consumed by the fixture electronics and ballast, as well as the surge current that occurs while the lamp is warming up. Not only can you use this information to impress your friends and family, but it also comes in handy for engineering power distribution systems.
– From Swami Candela’s Technopolis column in the April issue of PLSN
