Calculator Inputs
Example Data Table
These sample values show how connected load reduces after diversity.
| Area / Circuit | Connected (kW) | Diversity (%) | After diversity (kW) | Comment |
|---|---|---|---|---|
| Lighting & small power | 18.00 | 80 | 14.40 | Typical non-simultaneous use. |
| HVAC package units | 22.00 | 90 | 19.80 | Often high coincidence in hot months. |
| Lift & fire pump | 12.00 | 100 | 12.00 | Treat critical loads as continuous. |
| Total | 52.00 | — | 46.20 | Used for feeder sizing checks. |
Formula Used
- kW = kVA × PF
- kVA = kW ÷ PF
- 1-phase current: I(A) = kVA×1000 ÷ V
- 3-phase current: I(A) = kVA×1000 ÷ (√3 × V)
How to Use This Calculator
- Select an input unit (kW, kVA, or current).
- Enter PF, voltage, and phase for conversions.
- Choose Use load list to add multiple items, or enter one connected value.
- Select a diversity method: percentage or factor.
- Optionally apply a usage factor and growth allowance.
- Click Calculate to show results above the form.
- Use the CSV/PDF buttons in the results panel to download a report.
Technical Notes and Planning Guidance
1) Why after diversity matters on site
Connected load is the sum of installed nameplate values, but equipment rarely runs together. After diversity demand (maximum demand) supports practical feeder sizing, panel allocation, and transformer selection. Many projects also carry 10–25% spare capacity on the diversified figure for operational flexibility.
2) Typical diversity ranges used in projects
Common starting points include lighting and small power at 70–90%, socket outlets at 60–80%, and cooking equipment at 50–70%. Lifts, fire pumps, and life-safety loads are often treated near 100% because they must be available on demand. Mixed commercial areas frequently land around 80–90% when occupancy is predictable.
3) Percent versus factor selection
If your schedule states “diversity 80%,” the tool multiplies connected kW by 0.80. If it states “diversity factor 1.25,” the tool divides connected kW by 1.25. Use the format written in your tender documents to avoid double-reducing demand.
4) How kW, kVA, and current relate
Many procurement checks are in kVA, while installation checks often need current. The calculator converts kW↔kVA using power factor, then estimates current using voltage and phase. For example, 50 kVA at 400 V three-phase is about 72 A, while 50 kVA at 230 V single-phase is about 217 A.
5) Load list improves traceability
The load list mode separates HVAC, lighting, sockets, pumps, and special systems. Itemized inputs make reviews faster and reduce disputes during commissioning. Exports help keep assumptions visible in RFIs, progress meetings, and handover records.
6) Usage factor and growth allowance
Some teams apply a usage factor when duty cycles are known to be higher than standard assumptions. Growth allowance adds headroom for tenant changes or future equipment. A planning range of 5–15% growth on diversified demand is common early in design, then refined at detailed stage.
7) Worked example with realistic numbers
A floor with 18 kW lighting/small power, 22 kW HVAC, and 12 kW critical loads can be diversified to 46.2 kW using 80%, 90%, and 100% respectively (14.4 + 19.8 + 12.0). With PF 0.90, that equals about 51.3 kVA for feeder checks and preliminary breaker selection.
8) Good practice before finalizing sizes
Treat the output as a design estimate, then validate with duty cycles, simultaneous operation, and code requirements. Also review starting currents, voltage drop, and harmonics for sensitive equipment. Record your assumptions so the design remains auditable during changes and future expansions.
FAQs
1) What is “after diversity demand” in simple terms?
It is the realistic maximum demand after acknowledging that not all connected loads operate simultaneously. It helps size feeders, panels, and transformers without overestimating capacity.
2) Should I use diversity percentage or diversity factor?
Use whatever your specification states. A percentage multiplies connected kW, while a factor divides connected kW. Both reduce demand, but they are expressed differently.
3) Why does the calculator ask for power factor?
Power factor converts between kW and kVA. kVA is commonly used for transformer and generator checks, while kW is used for energy and demand planning.
4) Are the current results suitable for breaker selection?
They are an estimate at the entered voltage and phase. Final breaker selection should consider code rules, ambient temperature, conductor ratings, starting currents, and coordination studies.
5) How do I handle motors and starting currents?
Use this tool for steady-state demand planning, then separately check motor starting, inrush, and voltage dip. Large motors may require dedicated feeders or soft-start arrangements.
6) What growth allowance is common in building projects?
Many teams carry 5–15% growth on diversified demand, depending on tenancy uncertainty and client preference. Higher allowances may be used for shell-and-core or expansion-ready facilities.
7) Can I export what I entered for project records?
Yes. After calculating, use the download buttons to export CSV or PDF. The export includes key inputs, totals, and the optional load list for traceable reporting.