Direct answer
A load schedule records circuits and equipment on a consistent electrical basis, then applies only justified demand assumptions before reviewing totals and phase allocation.
What this calculation tells you
A load schedule is an audit trail for what is connected, how ratings were interpreted, which loads may operate together, and how the result is distributed. Its value is transparency: another reviewer should be able to trace every subtotal and assumption.
Demand factors, diversity, continuous-load treatment, motor allowances, and spare capacity are rule- and project-dependent. A general calculator should accept entered assumptions rather than invent universal factors.
Where it is used
Commercial electrical design
Coordinate panel schedules, tenant loads, equipment additions, and service-capacity studies.
Industrial facilities
Separate process, motor, heating, control, and standby loads across operating modes.
Temporary power
Plan construction or event distribution from a defined equipment list and credible simultaneity scenario.
Energy projects
Compare connected equipment with metered demand while preserving the difference between design and observed operation.
When this guide helps
- A new machine is proposed for an existing distribution board.
- Several single-phase loads need allocation across a three-phase panel.
- Standby and normal operating modes include different equipment.
- A contractor must explain why the demand total is lower than the connected total.
Normalize ratings before adding them
Equipment may be labeled in watts, volt-amperes, amperes, horsepower, or phase-specific current. Convert each item on a documented basis and do not treat real and apparent power as identical when power factor matters.
Record voltage, phase, quantity, duty, and source of each rating. A clean total built from mixed conventions is still unreliable.
Demand belongs to an operating story
A demand allowance should correspond to a defensible operating scenario or governing rule. Separate normal, startup, emergency, seasonal, and future cases instead of compressing them into one unexplained percentage.
Measured peak demand can inform an existing-facility study, but it may not represent future process changes or rare coincident operation.
Phase balance is more than equal arithmetic
Evenly distributing nameplate values can reduce nominal imbalance, yet real phase currents change as thermostatic, intermittent, and variable-speed loads cycle. Neutral loading and harmonics may require additional analysis.
The schedule should expose phase subtotals and the assumptions behind any reallocation so field labeling and documentation remain aligned.
Capacity is a coordinated conclusion
A schedule does not by itself size conductors, transformers, generators, switchgear, or protection. Verify applicable demand rules, continuous loads, fault levels, derating, equipment ratings, and expansion policy.
- Keep source ratings traceable.
- Model operating modes explicitly.
- Reconcile final documents with installed circuits.
Worked case: three phase totals
Entered phase real loads are 10, 8 and 6 kW.
Total 24 kW; average 8 kW; maximum deviation 2 kW or 25% of average.
Phase A is+25%, B 0%, C-25% relative to entered average.
This summary does not calculate neutral current or harmonics.
Reproduce this worked caseOpen Electrical Load Schedule Calculator
Worked case: move 2 kW from A to C
Phases become 8, 8, 8 kW.
Total remains 24 kW and entered deviation becomes 0%.
Ideal arithmetic balance is achieved in this simplified schedule.
Actual simultaneity, circuit constraints and phase connection must be verified.
Reproduce this worked caseOpen Electrical Load Schedule Calculator
load schedules and phase balance: compare assumptions, not just answers
Keep connected, demand and measured loads distinct. Balancing a schedule is not design approval or field switching instruction.
| Field scenario | Changed input | Calculated consequence |
|---|---|---|
| 10/8/6 | Average 8 | Max deviation 25% |
| 8/8/8 | Average 8 | 0% |
load schedules and phase balance: calculation checklist
- Load type/unit consistent
- Demand factors sourced
- Phases assigned explicitly
- Total reconciled
- Harmonics/protection separate
Practical questions
Frequently asked questions
Why is demand lower than connected load?
Because connected load assumes every listed item at its recorded rating, while demand reflects only justified simultaneity or prescribed factors. The basis must be stated.
Can I use breaker ratings as equipment loads?
Not automatically. A protective-device rating is not necessarily the equipment's expected or rated operating demand.
Does an equal phase total guarantee a balanced installation?
No. Actual timing, power factor, harmonics, and single-phase load behavior can produce a different operating balance.
Further reading
Authoritative sources
Use these primary and professional resources to check definitions, conventions, or requirements that may extend beyond this guide.