Calculateur de Section de Câble & Chute de Tension NEC 2026

NEC Table 310.16 specifies allowable ampacities of insulated copper and aluminum conductors rated up to 2000 volts, categorized by insulation temperature ratings (60°C, 75°C, 90°C).

Excessive voltage drop causes electric motors to overheat, appliances to underperform, lights to flicker, and electrical energy to be wasted as heat in conductor wires.

The National Electrical Code (NEC Fine Print Note 210.19) recommends that total voltage drop on a branch circuit should not exceed 3%, and total drop from service panel to furthest outlet should not exceed 5%.

For single-phase AC circuits, single-phase voltage drop is calculated using the formula: V_drop = (2 × K × I × L) / CM, where K is conductor resistivity, I is current in amps, L is one-way length in feet, and CM is circular mil area.

Standard 20-amp 120-volt branch circuits require a minimum of 12 AWG copper wire. For runs exceeding 70 feet, upsizing to 10 AWG copper prevents voltage drop from exceeding 3%.

Yes, aluminum conductors (e.g. AA-8000 series) are widely used for heavy feeder and subpanel circuits, but require larger wire gauges (e.g. 2 AWG aluminum vs 4 AWG copper) to achieve equivalent ampacity.

A continuous 50-amp 240V circuit for a Level 2 EV charger requires a minimum of 6 AWG copper wire or 4 AWG aluminum wire rated for 75°C terminals.

Conductor ampacity increases with higher insulation temperature ratings, but final wire sizing must conform to the lowest temperature rating of connected terminals (typically 75°C for standard breakers).

NEC Chapter 9 Table 1 limits conduit fill to 40% for three or more conductors in EMT or PVC conduit to prevent excessive heat accumulation and facilitate wire pulling.

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