Voltage Drop Calculator

AC voltage drop for 1-phase (2-wire) and 3-phase feeders using the NEC / IEEE 141 approximate formula V_d = K · I · L · (R cosφ + X sinφ) / 1000. Built-in cable R/X from NEC Chapter 9 Table 9 (Cu & Al, PVC & steel conduit, 75 °C).

CSV Input

References: NEC 2023 Chapter 9 Table 9 (AC Resistance & Reactance for 600-V Cables, 3-Phase, 60 Hz, 75 °C); IEEE Std 141-1993 (Red Book). NEC recommends ≤ 3% on branch circuits and ≤ 5% combined feeder + branch — see NEC 210.19(A)(1) Info Note 4 and 215.2(A)(1) Info Note 2. Single-phase uses K = 2 (2-wire); 3-phase uses K = √3.

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