Electric Load Calculator for Manufacturing

Calculate connected load, demand, and running current fast. Compare single-phase and three-phase equipment requirements easily. Support safer manufacturing power planning with organized electrical estimates.

Manufacturing Electric Load Input Form

Supply Type

Voltage (V)

Power Factor

System Efficiency (%)

Demand Factor (%)

Diversity Factor

Spare Margin (%)

Growth Margin (%)

Breaker Safety (%)

Energy Tariff per kWh

Equipment Schedule

Machine	Qty	Unit Power (kW)	Hours/Day	Days/Month	Utilization (%)

Example Data Table

Machine	Qty	Unit Power	Hours/Day	Days/Month	Utilization
CNC Machine	2	18.50 kW	10	26	80%
Air Compressor	1	11.00 kW	8	26	65%
Conveyor Line	3	4.20 kW	12	26	90%

Formula Used

Connected Load: Sum of quantity × unit power for all machines.

Running Load: Connected load × utilization factor.

Maximum Demand: Running load × demand factor ÷ diversity factor.

Future Demand: Maximum demand × (1 + growth margin).

Input Power: Future demand ÷ efficiency.

Apparent Power: Input power ÷ power factor.

Three-Phase Current: I = (kVA × 1000) ÷ (√3 × V).

Single-Phase Current: I = (kVA × 1000) ÷ V.

Recommended Breaker: Line current × breaker safety × spare margin.

Monthly Energy: Running load × hours/day × days/month.

Monthly Cost: Monthly energy × tariff.

How to Use This Calculator

Choose single-phase or three-phase supply type.
Enter system voltage, power factor, efficiency, and planning margins.
Fill in each machine row with quantity, power, operating hours, and utilization.
Set tariff if you also want an estimated monthly energy cost.
Press Calculate Electric Load to display results above the form.
Use the CSV button for spreadsheet records and the PDF button for printable reports.

Frequently Asked Questions

1. What does connected load mean?

Connected load is the total installed power rating of all listed machines. It assumes every device can run at its full rated output simultaneously.

2. Why is running load lower than connected load?

Running load applies each machine’s utilization percentage. This gives a more realistic estimate when equipment does not operate continuously at full rated power.

3. What is demand factor used for?

Demand factor reduces running load to reflect the likely peak demand. It helps size feeders, switchgear, and upstream power sources more realistically.

4. Why do I need diversity factor?

Diversity factor accounts for equipment not peaking at the same moment. A higher diversity factor lowers the combined maximum demand estimate.

5. How is current calculated for three-phase systems?

For three-phase supply, current equals apparent power in volt-amperes divided by the product of line voltage and square root of three.

6. What does the suggested breaker rating represent?

The suggested breaker rating applies safety allowance and spare margin to the calculated current. Final device selection should still follow local codes and coordination studies.

7. Can this calculator estimate energy cost?

Yes. Enter operating hours, monthly working days, and tariff per kWh. The tool multiplies estimated monthly energy by tariff to show cost.

8. Is this tool enough for final electrical design?

It is useful for planning, budgeting, and early sizing. Final design should also consider harmonics, motor starting, fault levels, cable derating, and regulations.