California State License No. 989035Residential & Commercial Electrical Contractor

HAIK ELECTRIC · ELECTRICAL REFERENCE

Electrical Calculators

Calculate watts, volts, amps, and ohms, find power, current, and voltage for a balanced 3-phase load, plan conduit hand bends, or estimate copper and aluminum wire sizes and voltage drop.

Wire Size & Voltage Drop ↓3-Phase Power ↓Conduit Bender ↓

Results

Power (W)

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Voltage (V)

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Current (A)

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Resistance (Ω)

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Try an example

Results are rounded to 8 significant digits. P means power; I means current.

3-Phase Power Calculator

For balanced 3-phase AC loads. Use RMS line-to-line voltage and line current (the current in one line).

Use the load’s actual power factor. A purely resistive load has a power factor of 1. Power in kW means total electrical input power across all three phases.

3-phase results

Real power (kW)

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Apparent power (kVA)

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Line-to-line voltage (V)

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Line current (A)

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P = √3 × V × I × PF ÷ 1,000

Try an example

Assumes a balanced load. Motor shaft output requires efficiency information; enter electrical input power here. Results alone do not determine wire or breaker size.

Conduit Hand Bender Calculator

Plan common EMT hand bends using practical field multipliers. Enter all measurements in the selected unit; decimal inches are accepted (for example, 2.5 for 2½ inches).

Choose a bender rated for this EMT size. Offset and saddle geometry uses your entered dimensions and angle.

Bend layout

Labeled conduit bend layoutSchematic bend locations and dimensions. Letters correspond to the bend guide below.

Field estimates: bend radius, springback, and alignment marks vary by bender. Confirm the take-up and center-bend mark on your actual tool and check a trial bend. Saddle heights include needed clearance; a three-point saddle is intended for a narrow obstruction. Dimensions are displayed to 3 decimal places; diagrams are schematic.

Manufacturer bending guide (Klein Tools)

COPPER & ALUMINUM · AC & DC

Wire Size & Voltage Drop Calculator

Find the smallest supported conductor meeting your voltage-drop target and ampacity requirement, or check a selected size. Enter the distance from source to load once; the return path is included automatically.

Ampacity & AC settings

Default PF = 1 and X = 0 provide a resistance-only estimate. For reactive AC loads, enter manufacturer reactance for the selected cable and arrangement. Recheck X after changing wire size; automatic sizing uses the same entered X for all candidates.

Confirm insulation and terminal ratings on the actual equipment. Default terminals are 60°C. Count loaded conductors according to the applicable code, including neutrals where required.

Wire sizing results

Calculation method & scope

Estimated conductor resistance at 75°C: R = K ÷ circular mils, with K = 12.9 for copper and 21.2 for aluminum, in Ω·cmil/ft. DC: ΔV = 2 × L × I × R. AC: ΔV ≈ M × L × I × (R × PF + X × √(1 − PF²)), where M = 2 for single-phase or √3 for balanced 3-phase and X is in Ω/ft. Three-phase voltage is line-to-line; current is line current.

Ampacity uses the NEC Table 310.16 family for insulated conductors in raceway, cable, or earth, with ambient and conductor-count adjustments and a terminal-temperature limit. Supported sizes: 14 AWG copper / 12 AWG aluminum through 500 kcmil; ambient through 50°C. Small-conductor protection limits are applied conservatively when choosing a size.

Planning estimate. AC skin effect and installation-specific resistance are not modeled. Confirm the locally adopted code, cable-specific restrictions, protective device, grounding, and equipment ratings before installation. Motor rules, mixed continuous loads, dwelling-service allowances, parallel runs, free-air ampacity, and leading power factor require a separate design. This tool does not choose a breaker.

Southwire ampacity reference (tables on pages 29–30) · Southwire voltage-drop reference

Understand the units

W · Power

Watts describe how quickly electrical energy is used.

V · Voltage

Volts describe the electrical push that drives current.

A · Current

Amps describe the flow of electric charge.

Ω · Resistance

Ohms describe how much a component resists current.

For DC circuits and purely resistive loads. For AC, use RMS voltage and current for a purely resistive load. Motors and other reactive loads require power factor or impedance information. These results alone do not determine wire size, breaker size, or installation requirements.