Electric Ref: Wire Size, Fill

Type the amps, get the wire size. Pick a conduit, see how many conductors fit. Electric Ref answers the questions electricians ask every day — in three taps, fully offline.

SIZE WIRES CORRECTLY

- Amps to conductor size with temperature correction, conductor bundling adjustment and termination limits applied automatically

- Copper and aluminum, 60/75/90°C insulation

- Small-conductor breaker caps built in

- Every answer shows WHY — the code articles and factors behind it

CONDUIT & BOX FILL

- Max conductors for EMT, RMC, IMC, PVC 40/80, ENT, FMC, LFMC and more

- THHN, XHHW, TW/THW wire types

- Box fill with device, clamp and ground allowances

MORE FIELD TOOLS

- Voltage drop (DC and AC methods, any power factor, conduit material)

- Motor full-load current, conductor and breaker sizing

- Equipment grounding and grounding electrode conductor sizes

- Transformer currents, Ohm's law wheel

REFERENCE CHARTS

- Hole saw and knockout sizes (triple-checked)

- NEMA plug and receptacle configurations

- Motor starter sizes, wire color codes

- Burial depths, conduit support spacing, wire properties

BUILT FOR THE FIELD

- 100% offline — works in basements, new construction, anywhere

- Big glove-friendly controls, screen stays awake

- No account. Your data never leaves your phone.

ONE-TIME PURCHASE

The free version includes the Ohm's law wheel, daily wire sizing and core reference charts. Electric Ref Pro is a single one-time purchase that unlocks every calculator and chart.

No subscription. No ads. No feature removals. Ever.

Values are based on the National Electrical Code®. Reference only — always verify with your locally adopted code edition and AHJ. NEC is a registered trademark of the National Fire Protection Association, which does not endorse this app.