Free trade calculators
Every one of these shows the formula and names the code table behind the answer, so you can check it against the book rather than trust it. All of them are also in the FieldDojo app, which works offline on the job.
- electricalAmpacity Derating Calculator
Derate conductor ampacity for ambient temperature and bundling per NEC 310.15 — correction factor, adjustment factor and arithmetic shown.
- electricalBreaker Size Calculator
Size a breaker from continuous and non-continuous load per NEC 210.20(A), rounded up to a standard 240.6(A) rating, with the arithmetic shown.
- electricalGround Wire Size Calculator
Size an equipment grounding conductor from the breaker rating, or a grounding electrode conductor from the service conductors, per NEC Tables 250.122 and 250.66.
- electricalMotor Full-Load Current Calculator
Look up motor full-load current from NEC Tables 430.248 and 430.250, plus the 125% conductor minimum per 430.22 — the table value the code requires.
- electricalNEC Load Calculation
Size a dwelling service with the NEC Article 220 standard method — lighting, range, dryer and HVAC demand factors applied, every line shown.