I have a customer that we have done a bunch of work for and on one of the building we replaced a huge piece of service gear and the inspector had no issues whatsoever, but this same customer has another building with a really old piece of junk gear that needs to be replace (they will but probably a year or so out) that is rated at 42k and what the issue is the power company replaced their transformer about six months ago from a 300kva to 500kva. Now we have to get a permit signed off, but we cannot because the fault current of this transformer exceeds the rating of the gear. The power company is dodging all the questions that I'm asking them and this is their last response "Per Std 0650.3010, the available fault current at the secondary bus of a 3-phase 208Y/120V pad-mounted transformer is 60,300A. However, this fault current drops to a lower level at the customer's gear. You can provide the transformer's impedance of 2.3 % and R/X=0.2 to the customer and let him calculate the available fault current at the gear." Can someone give me some advice? This gear is rated at 42k 120/208V 800amp fused (no idea what the fuses are rated at because they are 30 years old) and feed with parallel runs of 750MCM AL about 20'. Everything I'm coming up with still puts this fault current at way above what the gear is rated at. The power company is PSE.