NEC 2026 — Chapter 9, Tables 8 & 9 · K-Formula vs. AC Impedance · §210.19 (branch circuits) / §215.4(A)(2) (feeders)
System Type
Conductor Material
NEC Chapter 9, Table 8 · Table 310.16
Conductor Size
Construction — Method 1 / Table 8
Number of Parallel Sets310.10(G)(1)ⓘ
One-Way Distance (ft)
Line Current (A)
Voltage Source (V)
NEC Chapter 9, Table 9
Conduit Type
Method 1 — K-Formula
Chapter 9, Table 8 · DC-resistance basis · Quick field estimates
Method 2 — Table 9 AC Impedance
Chapter 9, Table 9 · AC impedance basis · Preferred for large conductors & long runs
Additional Scenarios
Other Scenarios →Side-by-Side Comparison
| Method | VD (V) | VD (%) |
|---|---|---|
| Method 1 — DC-resistance basis (Table 8, solid/stranded) | 0.00 | —% |
| Method 2 — AC impedance basis (Ze to neutral, per Ω/kft) | 0.00 | —% |
| Δ (Table 9 − K-Formula) | 0.00 | —% |
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