Electrical & Conduit Calculators
Wire gauge sizing, voltage drop, conduit fill, and electrical box fill calculations.
Available Calculators in Suite
4 active toolsElectrical Wire Size & Voltage Drop Calculator
Calculate single-phase, 3-phase, and DC voltage drop, recommended AWG/kcmil wire gauge, copper vs aluminum comparisons, and NEC Table 310.16 ampacity derating.
Electrical Conduit Fill Calculator
Calculate mixed conductor conduit fill percentage (EMT, PVC Sch 40/80, RMC, FMC, LFMC), NEC Chapter 9 Table 1 limits, and jam ratio warnings.
Electrical Box Fill Calculator
Calculate electrical box fill cubic-inch capacity per NEC 314.16 for mixed wire gauges, devices, clamps, and grounds with candidate box recommendations.
Residential Electrical Service Load Calculator
Calculate total residential electrical service load (VA and Amps) per NEC Article 220.82 for 100A, 150A, 200A, and 400A service panel sizing with EV chargers and heat pumps.
NEC Worked Solutions & Code Case Studies
Step-by-step mathematical proofs and code citations for real-world electrical design problems:
100ft 12 AWG at 20A 120V Voltage Drop
Calculate voltage loss and upsize conductor to 10 AWG to maintain the NEC 3% branch circuit threshold.
NEC Chapter 9 Table 1Three 4 AWG THHN in EMT Raceway
Determine minimum EMT trade size using Table 4 dimensions and 40% fill maximums.
NEC 314.16(B)Six 12 AWG, Two Clamps & Receptacle Box Fill
Calculate cubic inch volume requirements for conductor counts, internal clamps, and device yokes.
NEC 310.12200A Single-Family Dwelling Feeder Sizing
Apply the 83% residential service conductor demand factor to size copper or aluminum entrance conductors.
NEC 690.8(B)Solar PV Inverter Output Conductor Sizing
Calculate 125% continuous output current and minimum OCPD protection for grid-tied solar systems.
NEC Table 250.66200A Service Grounding Electrode Conductor
Size copper and aluminum grounding electrode conductors based on ungrounded service entrance size.
NEC Table 314.16(A)4x4 Deep Square Box Conductor Capacity
30.3 cu in volume allowances, conductor fill deductions, and device volume sizing.
NEC Chapter 9 Table 4Six 10 AWG THHN in 1/2" EMT Fill Check
Calculate cross-sectional area and 40% fill capacity limit (0.122 sq in threshold).
NEC 220.52(A)Kitchen Small Appliance Branch Circuits
Calculate 1,500 VA demand factors for two kitchen circuits and dedicated laundry branch.
NEC 440.32AC Unit Wire Sizing (MCA & MOP)
Determine branch circuit ampacity for 28.5A MCA and maximum 45A overcurrent protection.
NEC 430.2215 HP 460V 3-Phase Motor Branch Circuit
Calculate 125% FLC conductor rating (26.25A) and inverse time breaker sizing (50A).
NEC 220.61(B)Electric Range Feeder Neutral Sizing
Apply the 70% unbalanced neutral demand factor for household cooking appliances.
NEC 220.54Residential Clothes Dryer 5,000W Feeder
Calculate minimum 5 kW dryer demand or nameplate rating under Table 220.54.
NEC 450.3(B)45 kVA 480V-208V Transformer Full-Load Amps
Calculate 54.13A primary FLC, 124.91A secondary FLC, and 70A primary breaker sizing.
Technical Electrical Master Guides
Comprehensive code walkthroughs and engineering derivations:
Electrician's Guide to Voltage Drop
Formulas, resistance constants, NEC 3% vs 5% thresholds, and distance derating tables.
Master GuideNEC Conduit Fill Rules & Tables
Chapter 9 Table 1 percentages, 60% nipple exemptions, Table 4 dimensions, and jam ratios.
Master GuideSubpanel Feeder Conductor Sizing
Continuous load factors, Table 310.16 ampacity, and long-run voltage drop calculations.