Volt Drop Check & Plug

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.