A. NEC — NFPA 70-2020 (National Electrical Code)
NFPA 70-2020 — the customer-side premises wiring code. NEC Article 250 grounding + bonding, NEC Article 430 motor branch circuits + feeders.
Lessons
NEC Article 250 — grounding and bonding
The most-tested PE blueprint topic. 250.4(A) five general requirements (earth is NOT an effective ground-fault current path). 250.20 which AC systems must be grounded. 250.50/52 grounding electrode system. Table 250.66 GEC sizing + rod/pipe/plate reduction. 250.118/Table 250.122 EGC types + sizing. 250.28/96/102 bonding. All values verified against NEC 2020.
NEC Article 430 — motor branch circuit & feeder sizing
Use TABLE FLC (NEC 430.247-430.250) for conductors + branch OCPD; NAMEPLATE FLA only for overload (430.32). Conductors: 125% × FLC (430.22). Branch OCPD: 250% inv-CB / 300% NTD fuse / 175% DE fuse — × FLC (430.52). Overload: 115-125% × FLA. Disconnect ≥115% FLC within sight (430.102). Feeder: 125% LARGEST + 100% OTHERS (430.24). VFDs: Article 430 Part X.