Load schedule builder calculator
Build an Australian load schedule worksheet from entered circuit rows, phase allocation and duty factors.
Irow = Iload x quantity; Iduty = Irow x duty_% / 100; PhaseTotal = sum(Iduty allocated to each entered phase); margin = phase_limit - max(PhaseTotal)- Row current, quantity and duty factor are entered by the user.
- Three-phase rows are added to each phase total as a worksheet convention.
- The review limit is entered by the user.
- The calculator does not determine maximum demand or board capacity.
| Variable | Meaning | Unit | Use |
|---|---|---|---|
| Iload | Row current | A | Entered current for one item in the load row. |
| Irow | Connected row current | A | Row current multiplied by quantity. |
| Iduty | Duty-adjusted current | A | Connected row current multiplied by user-entered duty factor. |
| PhaseTotal | Phase total | A | Sum of duty-adjusted rows allocated to each phase. |
| phase_limit | Phase review limit | A | Entered value used to compare the highest phase total. |
| margin | Review margin | A | Entered phase review limit minus highest phase total. |
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Load schedule builder calculator technical guide
Build an Australian load schedule worksheet from entered circuit rows, phase allocation and duty factors.
Use this calculator when a small load schedule needs to be written into a traceable worksheet before maximum-demand, phase-balancing or spare-capacity review. The page keeps row current, quantity, phase allocation and duty factor visible so the source basis can be checked later.
Field Use Cases
| Work setting | Real question | Useful action from this page |
|---|---|---|
| Workshop board | Which phase receives the highest entered row total? | Add duty-adjusted rows into L1, L2 and L3 totals. |
| Tenancy fit-out | Are row groups visible before maximum-demand review? | Keep connected and duty-adjusted totals beside row labels. |
| Board alteration | Does the new row change one phase materially? | Compare the highest phase total with the entered review limit. |
| Maintenance record | Which rows need source confirmation? | Export row labels, duty factors and phase allocation. |
| Downstream review | Where do the totals go next? | Carry the result to maximum demand, phase balancing or spare capacity. |
This page is intentionally a row worksheet. It does not hide a demand-factor table, board-capacity rule or phase-movement decision.
Data checklist
| Value | Where it normally comes from | Stop if |
|---|---|---|
| Schedule reference | Board, tenancy, load schedule or drawing reference | The boundary of the schedule is unclear. |
| Row current | Load-current calculation, equipment data or measured record | The current basis differs across rows. |
| Quantity | Circuit list, equipment count or schedule row | The row combines unrelated load types. |
| Duty factor | Project, engineering or documented source value | The factor is copied without source context. |
| Phase allocation | Board schedule or planning record | The phase assignment is not known. |
The worksheet works best when all rows describe the same operating state. Mixing peak, connected, measured and future values without labels makes the result harder to interpret.
Review Workflow
| Step | Record to check | Move to |
|---|---|---|
| Define the schedule boundary | Board or tenancy reference | Enter row currents and quantities. |
| Confirm row basis | Connected, measured or planned current | Enter user source duty factors. |
| Allocate phases | L1, L2, L3 or balanced three-phase | Read phase totals. |
| Compare the highest phase | Entered phase review limit | Phase balancing or capacity review. |
| Choose next worksheet | Demand, capacity or cable handoff | Use the linked calculator that owns that task. |
If the highest phase total is above the entered limit, treat the result as a review prompt. It does not say a circuit must move, a board is overloaded or a supply upgrade is needed.
Worked schedule record
A workshop schedule contains two 32 A outlet rows on L1, one 18 A air-conditioning row on L2 at an 80% duty factor, and one 24 A three-phase equipment row at a 75% duty factor. The entered phase review limit is 80 A.
The connected row total is 106 A. After duty factors, the row total is 96.4 A. The three-phase equipment row contributes 18 A to each phase, so the phase totals are 82 A on L1, 32.4 A on L2 and 18 A on L3. L1 is the highest phase and is 2 A above the entered review limit.
| Value | Result |
|---|---|
| Connected row total | 106 A |
| Duty-adjusted total | 96.4 A |
| L1 total | 82 A |
| L2 total | 32.4 A |
| L3 total | 18 A |
| Highest phase | L1 |
| Review margin | -2 A |
The next question is not solved by this page. The result should move to phase balancing if allocation matters, maximum demand if demand factors need full review, or spare capacity if the board rating is the comparison point.
Method boundary
| Method element | What this page does | What remains outside |
|---|---|---|
| Connected row current | Multiplies row current by quantity. | Equipment selection and measured load quality. |
| Duty-adjusted current | Applies the user-entered duty factor. | Source selection for the factor. |
| Phase totals | Adds rows to entered phase labels. | Final circuit movement or board design. |
| Review margin | Compares highest phase with an entered limit. | Maximum-demand determination and supply connection review. |
Keeping the boundary narrow makes the record useful. The load schedule can be corrected without rewriting downstream calculators.
Stop points
- Row currents come from different operating states without labels.
- Duty factors do not have a source basis.
- The phase assignment is unknown or temporary.
- A three-phase row is not actually balanced on the project basis.
- The result is being treated as a maximum-demand or spare-capacity decision.
When a stop point appears, keep the exported worksheet as a question record and resolve the source values before using the totals elsewhere.
Workshop load schedule
A workshop schedule groups outlet, air-conditioning and three-phase equipment rows before phase review.
- Schedule reference
- LS-1
- Rows
- 3
- Phase review limit
- 80 A
- Connected row total106 A
- Duty-adjusted total96.4 A
- Highest phase total82 A
Carry the row record into the next load review only after source values are checked.
L1 is above the entered review limit, so the row allocation should be reviewed before downstream demand work.
- Rows use entered current values.
- The duty factor is entered by the user.
- Three-phase rows are added to each phase total.
Tenancy draft schedule
A tenancy fit-out schedule keeps three single-phase row groups visible before maximum-demand review.
- Schedule reference
- TENANCY-LS
- Rows
- 3
- Phase review limit
- 70 A
- Connected row total92 A
- Duty-adjusted total74.4 A
- Highest phase total28 A
Carry the row record into the next load review only after source values are checked.
The entered phase totals remain below the review limit for this schedule record.
- The row currents are entered on the same basis.
- The review limit is a user-entered comparison value.
- No maximum-demand table is embedded.
Alteration allowance
A board alteration worksheet adds a new single-phase row beside existing balanced equipment.
- Schedule reference
- ALTERATION-LS
- Rows
- 3
- Phase review limit
- 95 A
- Connected row total100 A
- Duty-adjusted total80.4 A
- Highest phase total70.4 A
Carry the row record into the next load review only after source values are checked.
The added L1 load is visible in the phase totals and can be carried into phase-balancing review.
- Existing plant is treated as balanced.
- Future allowance is entered by the reviewer.
- Protection and supply review remain separate.