I am involved in a tenet improvement project on a commercial property. As part of the scope of work I rewired the building, installing a new meter/main disconnect box and panel.
I went into the building department to speak to the electrical inspector about the sequence of inspections and I was told that I need to obtain a letter from SCE detailing the AIC of their protective device(s) at the vault that supplies the building in question. I have never been asked this before. Why would he ask for this kind of information? What is he really looking for? Is he looking to have me install a main breaker with a certain Interrupting Rating? If SCE has a device that can handle 42,000 amperes, why would it matter if the main can only handle 10,000 amperes? What should the rating be on the my main breaker? What does the NEC say?