Conduit Fill Chart: How Many Wires Fit in EMT? - NEC caps conduit fill at 40% for 3 or more wires: 1/2 in EMT holds 9 THHN 12 AWG, 3/4 in holds 16, 1 in holds 26. Full chart, worked math, common mistakes.
How to Bend EMT Conduit: 90s, Offsets & Saddles - Subtract the take-up (5" for 1/2" EMT, 6" for 3/4"), mark, and bend to 90. Offsets: multiplier x depth between marks, plus shrink. Charts and worked examples.
Conduit Bending Multipliers & Offset Shrink Chart - Offset multipliers: 10° = 6.0, 22.5° = 2.6, 30° = 2.0, 45° = 1.4, 60° = 1.2. Marks = depth × multiplier; shrink runs 1/16" to 1/2" per inch of depth.
Box Fill Calculation Explained (NEC 314.16) - NEC 314.16 box fill: each conductor counts at its volume allowance (14 AWG = 2.0 cu in, 12 AWG = 2.25), each device counts as 2, all grounds as 1, clamps as 1.
Wire Size & Ampacity Chart (NEC 310.16) - NEC 310.16 copper chart: 12 AWG takes a 20 A breaker, 10 AWG 30 A, 8 AWG 50 A at 75°C, and 2 AWG covers 100 A. All three columns, derating, worked examples.
Conductor Derating in Conduit (NEC 310.15) - More than 3 current-carrying conductors in a conduit cuts ampacity: 4-6 wires keep 80%, 7-9 keep 70%, 10-20 keep 50%. Derate THHN from the 90C column.
Ground Wire Size Chart: EGC (250.122) & GEC (250.66) - NEC 250.122 copper EGC sizes: 15 A = 14 AWG, 20 A = 12, 30-60 A = 10, 70-100 A = 8, 110-200 A = 6. GECs follow 250.66 instead. Charts and worked examples.