Load Inputs
Enter planning assumptions. Use nameplate data and documented operating conditions.
Example Data Table
This planning example uses three-phase equipment at 415 V.
| Load group | Connected kW | Demand factor | Power factor | Demand kVA |
|---|---|---|---|---|
| Motors | 130.43 | 80% | 0.86 | 121.33 |
| Process equipment | 45.00 | 75% | 0.92 | 36.68 |
| Lighting | 12.00 | 100% | 0.95 | 12.63 |
| HVAC | 25.00 | 85% | 0.90 | 23.61 |
| Other load | 8.00 | 70% | 0.88 | 6.36 |
Formula Used
Converts mechanical motor output into expected electrical input.
Applies the expected peak use for each load group.
Converts real demand into transformer and conductor loading.
Reduces group demand when peaks are unlikely to overlap.
Adds continuous-duty treatment and a reserve for planned growth.
For single phase, omit √3 from the denominator.
How to Use This Calculator
- Choose the supply arrangement and enter the nominal voltage.
- Enter motor shaft output, efficiency, and motor power factor.
- Add process, lighting, HVAC, and miscellaneous electrical loads.
- Set realistic demand factors for each load group.
- Apply a simultaneity factor, continuous loading factor, and spare capacity.
- Enter available transformer and feeder values for quick capacity checks.
- Review the result, then complete detailed code, protection, and site studies.
Industrial Electrical Load Planning
Industrial electrical load planning begins with equipment data. A plant may contain motors, process heaters, lighting, ventilation, compressors, pumps, and controls. Their nameplate ratings rarely operate together at maximum output. A useful calculation separates connected load from expected demand. It also records voltage, phase arrangement, efficiency, power factor, operating hours, and reserve capacity. This approach helps teams size feeders, transformers, switchgear, and standby margins with fewer assumptions.
Start With Connected Load
Start with connected load. Add the rated kilowatts for every known device. For motors, distinguish shaft output from electrical input. Motor efficiency converts output power into input power. Power factor then converts real power into apparent power. Apparent power is important because transformers and conductors respond to current and kVA. Low power factor can increase current even when useful mechanical output stays unchanged.
Apply Realistic Demand Factors
Apply demand factors to each load group. Motors may run only during production. Lighting may operate throughout a shift. HVAC demand can rise during hot weather. Process equipment can cycle on schedules. A simultaneity factor accounts for groups that do not peak together. Use realistic operating records whenever they exist. Conservative planning assumptions are useful when records are unavailable. Document every assumption for design review.
Protect Capacity for Expansion
Add continuous loading and spare capacity after the coincident demand is calculated. Continuous loads may require a higher design multiplier. Spare capacity supports future machines, process growth, and small changes in production. Select the next standard transformer rating above the calculated design kVA. Then compare calculated current with the planned feeder ampacity. A passing result does not replace conductor derating, protection coordination, fault duty, voltage drop, harmonic, or starting-current studies.
Review Energy Separately
Use energy estimates as a separate planning tool. Multiply coincident kW by operating hours and working days. This gives a practical monthly energy estimate. Multiply by the energy rate for a preliminary cost figure. Review the result when schedules or production volumes change. Verify final equipment ratings with approved drawings, local rules, and qualified electrical professionals. Safe industrial installations depend on verified field conditions and coordinated design decisions.
Good data improves every output. Use manufacturer documents for rated power, efficiency, and power factor. Check whether motor values represent output or input. Record equipment that is seasonal, intermittent, or planned for future installation. Revisit the calculation after commissioning, because measured demand often reveals better diversity assumptions.
Frequently Asked Questions
Connected load is the total installed electrical input of all listed equipment. It assumes every item is available. It does not assume every item runs at the same time.
Transformers, switchgear, and conductors are affected by current. kVA combines real power with power factor, so it is useful for evaluating electrical capacity.
The calculator divides motor shaft output by efficiency. A 100 kW motor with 90% efficiency needs about 111.11 kW of electrical input at full output.
It estimates the share of separate group demands likely to happen together. A lower value reduces the combined peak where equipment schedules do not overlap.
Spare capacity accommodates foreseeable expansion, small load changes, and uncertainty. It is a planning allowance, not a substitute for checking actual future equipment.
No. Final feeder selection also needs local rule checks, conductor derating, installation conditions, voltage drop, protection coordination, fault duty, and motor starting review.
Use the factor required by the applicable rules and the equipment duty. Some loads are continuous, while others are intermittent or governed by different requirements.
No. Breaker selection requires more than load current. Consider conductor protection, short-circuit rating, motor protection, coordination, inrush, and applicable installation rules.
It uses coincident kW, average operating hours, and operating days. It is a planning estimate and does not model demand charges, seasonal changes, or production variation.
Update it when equipment ratings, production schedules, transformer selections, or operating patterns change. Field measurements after commissioning can improve future demand assumptions.
No. Use qualified review before energizing every industrial electrical installation.
Preliminary planning estimate; qualified electrical design verification remains essential.