Volt Drop Check & Plug

Voltage drop, cable sizing, ampacity, breaker selection, power conversion, and a NEMA/IEC plug reference — all in one iPhone app. Japanese/English UI. Works offline.

Volt Drop Check & Plug is an iPhone-only electrical calculation toolkit for field electricians, maintenance technicians, and design engineers. Stop juggling paper tables, calculators, and spreadsheets — switch between tabs and get the answer you need in seconds.

■ What's inside

1. Voltage Drop Calculator • Inputs: supply voltage, load current (or power in W), cable length, conductor material (copper / aluminum), insulation (PVC 70°C, XLPE 90°C, heat-resistant PVC 105°C), circuit type (DC / 1-phase 2-wire, 3-phase 3-wire), power factor, and optional reactance. • Outputs: ΔV, drop %, terminal voltage, loop resistance, and assumed conductor temperature. • GOOD / CAUTION / NG verdict badge with a one-line explanation, improvement suggestions, risk notes, and basis notes. • Round-trip ×2 applied automatically for DC / single-phase; √3 factor applied for three-phase.

2. Cable Size Selection (reverse calculation) • From load current, voltage, cable length, allowable drop %, material, circuit type, power factor, and ambient temperature, get the minimum required conductor area and a recommended cable size. • Side-by-side comparison of common sizes with PASS / FAIL / BEST indicators.

3. Ampacity Calculator • From conductor material, size, installation method (free air / in conduit / bundled), insulation type, ambient temperature, and grouping count, see base ampacity with temperature and grouping correction factors. • Corrected ampacity plus a per-installation-method summary.

4. Breaker Selection Guide • From circuit current, circuit voltage, usage (general load / motor / lighting / IT·server), and phase (single / three), get a recommended rating (AT), frame size (AF), and type (MCCB / MCB / ELCB). • Earth-leakage (ELCB) recommendation is highlighted automatically where appropriate. Includes a type guide.

5. Power Calculator (W ↔ VA ↔ kVA ↔ var) • Convert between active power (W / kW), apparent power (VA / kVA), reactive power (var / kvar), and phase angle φ from voltage, current, and power factor. • Three input modes: V×A, W, or VA. Single-phase / three-phase switchable.

6. NEMA / IEC Plug Quick Reference • A searchable cheat sheet for plugs and connectors — useful for overseas sites and imported equipment. Filter by code, voltage, and more.

■ Designed for the field • One-tap Japanese / English UI toggle (selection is remembered). • All calculations run on-device — works reliably even with poor signal. • Clear separation of inputs and results, with verdict badges and plain-language notes. • iPhone-first layout tuned for one-handed use.

■ Great for • Field electricians and contractors • Facility and maintenance technicians • Plant and building-services engineers • Solar, energy-storage, and EV-charging designers • Teams working with imported or overseas equipment • Electrical students and trainees

■ Important Results are reference values based on generic targets (e.g., 3% voltage-drop goal, 5% maximum). Always follow your local codes, internal standards, and equipment specifications for actual design and installation.