What do the 1, 2, 3, CS, MC and CC grades of ASME N certificate and NPT certificate mean respectively?
I checked, and the general situation is as follows:
N certificate: related to ASME code-1 volume 3 NB; NC classification-level 2; ND classification-level 3; NE grade -MC grade; NF coil bracket; NG coil -CS core support; Class 1 components of NH winding-high temperature equipment.