Evidence

Sources and limitations

No professional validation. These sources provide context only. They do not validate this site for design, purchasing, wiring, installation or regulatory assessment. Refer the final installation to a qualified electrical professional.

Reviewed 1 August 2026. Links lead to standards publishers or manufacturers. Edition, local adoption, project conditions and manufacturer compatibility must be established for the actual installation. Restricted tables are not reproduced.

IEC 60364-5-52 publisher page — wiring-system selection and voltage-drop context; no table from the standard is embedded here.
IEC 60228:2023 publisher page — conductor resistance requirements and nominal conductor areas; it is not an ampacity table.
IEC 60034-2-1:2024 publisher page — motor-efficiency test methods; the worksheet relies on user-entered data.
IEC 60947-4-1:2023 publisher page — contactor and motor-starter scope; the worksheet produces no equipment determination.
ABB Electrical installation handbook — documents voltage-drop treatment using resistance, reactance and load power factor.
ABB motor starting application note — documents motor-specific locked-rotor and starting behavior.
Schneider Electric star-delta guidance — manufacturer context for motor terminals, connection and reduced-torque conditions.

Formula basis

Estimated current uses output power, voltage, efficiency and power factor. Optional starting-current arithmetic uses a user-entered multiplier. Cable voltage-drop arithmetic uses user-entered R and X values, length and power factor. Three-phase uses √3 × I × L × (R cosφ + X sinφ); single-phase uses 2 × I × L × (R cosφ + X sinφ). Conductor loss uses the user-entered R value. No material constants are embedded.

Input provenance

The user must obtain R and X from the relevant cable manufacturer or a qualified electrical professional. Entering a conductor area only records the scenario; it does not affect a size determination because this site performs none. Blank or unconfirmed cable evidence causes cable outputs to be withheld.

Star-delta boundary

The questionnaire only records whether prerequisites have been documented. It does not determine suitability, transition method, timing, switching arrangement, component ratings or installation.

Excluded

Fault current, disconnection time, earth fault, short-circuit withstand, ampacity, derating, installation method, harmonics, protection coordination, local rules, manufacturer compatibility, enclosure design, EMC, commissioning and installation are outside the model.