A. Wiring methods and installations (NEC 430, NESC C2)
NEC Article 430 motor circuits + branch/feeder sizing; NESC C2-2023 overhead/underground utility clearances.
Lessons
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.
NESC clearances — utility-side overhead + MAD (IEEE C2-2023)
NESC (IEEE C2-2023) governs the utility side of the service point; NEC (NFPA 70) governs the customer side. Four NESC parts: supply stations, overhead lines, underground lines, work rules. Rule 232 + Table 232-1: vertical clearances by surface — road 18.5 ft / pedestrian 14.5 ft / rail 26.5 ft (0-22 kV open). Residential driveway ≤ 300 V = 12.5 ft. Rule 232C1a voltage adder +0.4 in/kV above 22 kV. 232C1b altitude +3% per 1000 ft above 3300 ft (>50 kV). Rule 234: 22.5 ft vertical above pools (Table 234-3). Rule 235/236 conductor + climbing space. Part 4 Table 441-1 Minimum Approach Distance for live-line work — distinct from NFPA 70E RAB.