Hello All! Hope all of you have been hanging in there. Wife & I finally got internet back out here in the sticks! WooHoo! I have been asked to bid changing a Single Phase 400 Amp, 120/240V Single Phase Service over to a new Three Phase, 277/480V service, primarily for the customers new 460V pressure washers. An isolated single-phase transformer will be required for his new 120V plugs, lights, etc. Anyone know where I could find information/calculation on sizing the new KVA transformer that I will be needing? Thanks!
I thought about going with 120/208V 3 phase secondary, which would serve his plugs, lights, compressor just fine. But there are currently 2-100 Amp 120/240V, single phase disconnects, which serve 2 permanent office trailers, which have to be powered back up. So single phase secondary is a must now. Yes, POCO is requesting a Load Sheet from me before they will hook up the new 480/277/400A service. Which the size of my secondary xfr is all I'm lacking. On top of that, customer has informed me he "might" add on in 4-5 years if business is good. Thanks for info all!