tx2step
Senior Member
- Location
- North Texas, DFW area
I'm installing 2 new single phase 240/120V 400A Main Circuit Breaker panels (loadcenter construction), feeding them from a 167KVA single phase 240/120V pad mount transformer. The power Co says there is 69,500 maximum fault current amps available at the secondary lugs of the xformer. I will be feeding each new panel with 2 each 30 foot long parallel #250 MCM aluminum XHHW conductors per phase & neutral, in 2 each parallel PVC conduits. I ran that info through a bussman fault current calculation program (1997, version 1) and came up with 41,500 maximum available fault current amps at the main lugs of each new panel. Does that sound about right? The new panels will be fully rated at 42K AIC. Does anyone see any problems with this arrangement? The 2 panels will be installed side by side, for a total capacity of 800A. The minimum conductor length between the xformer lugs & panel Main CB lugs will be 30 feet -- maybe a few feet longer. Metering will be done with CT's in the xformer.