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Electrical

Voltage Drop

Calculate voltage drop and percent drop for wire runs using NEC Table 8 resistance values.

Safety/code-sensitive estimate. This calculator is not a substitute for licensed professional review, applicable code requirements, manufacturer instructions, field verification, permits, or inspections. Do not rely on this result as the sole basis for work that could affect life safety, fire safety, electrical safety, structural safety, public safety, property damage, code compliance, or required licensure.

Formula: VD = (factor × L × I × R) / 1000 — factor 2 (1-phase) or √3 (3-phase)

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