martsco11
Member
- Location
- Anaheim, CA US
Gentlemen, I have an existing 45kva xfmr (480 3ph to 120/208v 3ph) that I need to upgrade to a 75kva. The existing conduit run is 400' of 1" emt. I need to upgrade the wire to at least #2 thhn to handle the 90-100amp primary. According to the wire fill table I can fit 3 - #2 wires into the existing conduit. Here's the question...
Do I need to derate the wires (use larger wires), or can I re-tap the xfmr to accommodate the voltage loss (3%)? I'm trying not to replace the conduit... Most xfmrs have taps to allow for lesser or greater voltages.
Do I need to derate the wires (use larger wires), or can I re-tap the xfmr to accommodate the voltage loss (3%)? I'm trying not to replace the conduit... Most xfmrs have taps to allow for lesser or greater voltages.