Motor feeder planning worksheet

Screen the cable. Understand the start. Build a reviewable panel brief.

Estimate motor current, compare starting methods, inspect voltage drop and assemble a preliminary BOM—without hiding the assumptions.

Educational planning only · Not code compliance · Qualified review required

Interactive MVP

Motor Cable & Starter Panel Planner

Use motor nameplate values where available. Defaults are examples, not recommendations.

1 · Motor and supply Motor output

Phase Line voltage (V) Efficiency (%) Power factor Duty

2 · Cable route Conductor material One-way cable length (m) Installation planning factor Ambient planning factor Allowed running voltage drop (%)

These factors are sensitivity inputs, not values copied from an installation standard. Replace them during professional review.

3 · Start and operating cost Starting method Starting-current multiplier Local DOL preference threshold (kW)Illustrative, user/jurisdiction configurable and not an IEC cutoff. Enter 0 to disable. Annual operating hours Energy tariff per kWh

Currency is whatever currency your tariff uses. Small motors default to DOL planning where local supply rules allow; star-delta is usually unnecessary/uneconomic, not technically impossible. Starting multipliers vary with motor, load, supply and equipment setup.

Quote worksheet

Build a supplier-priced BOM

Add vendor-verified prices. The total is a budgeting framework, not a panel design or quotation.

Component	Qty	Unit cost	Line total
			0.00
			0.00
Estimated component subtotal			0.00

Method and limits

Why the output is a shortlist, not a specification

Modelled

Current from output power, voltage, efficiency and power factor
Starting-current sensitivity
Resistance-only voltage drop at a 75°C planning temperature
Conductor loss and annual energy-cost sensitivity

Not modelled

Jurisdictional cable ampacity tables and wiring methods
Fault level, earth loop, disconnection time or short-circuit withstand
Breaker/fuse/contactor coordination and selectivity
Harmonics, reactance, VFD reflected wave, EMC or thermal enclosure study

Standards context: IEC 60364-5-52 covers wiring-system selection and voltage-drop considerations; IEC 60947-4-1 covers electromechanical contactors and motor starters. Access the current edition through the standards publisher or your authority. This site does not reproduce restricted tables or claim compliance.

Star-delta is not selected from motor power alone. It requires a three-phase motor with six accessible terminals, a motor designed to run delta at the line voltage, a load able to accelerate with reduced star torque, and a documented reason to reduce network inrush. Incorrect transition can create current and torque peaks.

Review sources and evidence boundaries →