Electric Ref: Wire Size & Fill

Ampacity, conduit fill, boxes

Free · In‑App Purchases · Designed for iPad. Not verified for macOS.

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 calculations never leave 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.

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Stability and reliability improvements.

Version 1.0.1

The developer, Gun woo Kim, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Linked to You

    The following data may be collected but it is not linked to your identity:

    • Usage Data
    • Diagnostics

Privacy practices may vary, for example, based on the features you use or your age. Learn More

Accessibility

The developer has not yet indicated which accessibility features this app supports. Learn More

Information

Seller
Gun woo Kim
Size
31.1 MB
Category
Productivity
Compatibility
Requires iOS 13.0 or later.
  • iPhone
    Requires iOS 13.0 or later.
  • iPad
    Requires iPadOS 13.0 or later.
  • iPod touch
    Requires iOS 13.0 or later.
  • Mac
    Requires macOS 11.0 or later and a Mac with Apple M1 chip or later.
  • Apple Vision
    Requires visionOS 1.0 or later.
Languages
English
Age Rating
4+
In-App Purchases
Yes
Copyright
© 2026 WittyApps
  • Privacy Policy

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