Electrical calculators
Check conductor size, raceway fill and service capacity against the NEC tables, with every table and demand factor shown.
Voltage drop calculator
Drop in volts and percent for copper or aluminum, single-phase, three-phase or DC.
Conduit fill calculator
Fill percentage and the smallest EMT, rigid or PVC conduit for a mix of THHN conductors.
Electrical load calculator
Dwelling service size by the NEC 220.82 optional method, with every demand factor shown.
Wire size & ampacity calculator
Conductor size and breaker from the load, with ambient correction and bundling adjustment applied.
The order most jobs follow
- Load. Work out the calculated load first. For a dwelling service, that is an Article 220 calculation, which sets the service or feeder size.
- Conductor size. Pick the conductor by ampacity from Table 310.16, applying correction and adjustment factors where they apply.
- Voltage drop. Check the drop on long runs. If it exceeds the 3% recommendation, go up a size or more.
- Raceway. Size the conduit for the final conductors, including the equipment grounding conductor, against the Chapter 9 fill limits.
Each step can change the one before it. Upsizing for voltage drop means larger conductors, and larger conductors may need a larger conduit.