Runway and taxiway lighting load and power, circuit by circuit, from fixture counts and primary cable lengths, in kW and kVA.
List each series circuit, say whether it serves the runway or the taxiway, and enter the fixtures and cable on it. The tool adds fixture load, isolating transformer losses and cable I²R loss for every circuit, then reports kW and kVA for the runway, the taxiway and the whole airfield lighting system, with a CCR loading check on each circuit.
One row per CCR circuit. Current is the CCR output at full brightness, normally 6.6 A, so it matches the fixture watts entered below. Loop cable is the full series loop out and back, that is the total primary cable in the circuit. Leave it at 0 to ignore cable loss.
| Circuit | System | Current (A) | Primary cable | Loop cable (m) | CCR rating |
|---|
Enter the power each fixture draws at full brightness (the 6.6 A step), from the manufacturer's data sheet, and the circuit it is on. The values shown are placeholders typical of incandescent edge lights; LED fixtures draw much less.
| Circuit | Fixture type / description | Quantity | Watts each (W) | Subtotal (W) |
|---|
Planning assumption applied to every fixture. FAA AC 150/5345-47 minimums are 80 % for 30/45 W and 65 W, 85 % for 100 W and 150 W, and 90 % for 200 W and above, so 90 % is optimistic for the small sizes. Replace it with data sheet values.
Used to convert kW to kVA and to estimate output voltage. Planning assumption. FAA requires at least 0.95 for transformers at rated load. Use the measured value for LED fixtures, which often differ from incandescent loads.
Copper resistance rises about 0.393 % per °C above 20 °C.
Your project's own design rule, not a standard value.
| Circuit | System | Fixtures | Fixture (W) | Transformer loss (W) | Cable loss (W) | Total (kW) | Total (kVA) | Voltage (V) | CCR check |
|---|
Each circuit is calculated on its own, because each has its own CCR. The runway, taxiway and system totals are the sums of the circuits.
For each circuit, sum quantity times rated watts over the fixture types assigned to it, at full brightness.
Dividing by efficiency gives the power the primary circuit has to supply to the transformers. The difference is the transformer loss. One efficiency is applied to every fixture, so use a measured or data-sheet value where you have it.
The cable carries the full series current of that circuit, so its loss is I² times the loop resistance, corrected for temperature.
P is the real power at the CCR output, S its apparent power and V the approximate output voltage. The voltage is an approximation for quick checking. It ignores secondary cable and connector losses, and it is not a substitute for a voltage drop check.
The kVA values add in the same way because one power factor is applied to every circuit. Each circuit is then compared with the CCR you selected for it, and the smallest standard CCR that fits within your loading limit is shown.
| Item | Value |
|---|---|
| R1 runway: 100 × 45 W (4,500 W) at 90 % transformer efficiency | 5,000 W |
| R1 cable: #8 AWG, 4,000 m, 6.6 A | 359 W |
| R1 total at PF 0.95 | 5.36 kW, 5.64 kVA |
| R1 on a 7.5 kVA CCR | 75 % |
| T1 taxiway: 60 × 30 W (1,800 W) at 90 % transformer efficiency | 2,000 W |
| T1 cable: #8 AWG, 3,000 m, 6.6 A | 269 W |
| T1 total at PF 0.95 | 2.27 kW, 2.39 kVA |
| T1 on a 4 kVA CCR | 60 % |
| System total | 7.63 kW, 8.03 kVA |
It does not size the cable for voltage drop or insulation, model brightness steps, or account for secondary cable, connectors, lamp-out conditions or the CCR's own losses and input power factor, so the result is the load at the CCR output, not the supply demand. Stop bars, guard lights, approach lighting and signs go in as fixture rows like any other fixture, as long as you enter their watts (choose Runway or Taxiway for the system they belong to). Use Calculator #15 and #36 for cable drop and size, and #51 for CCR efficiency.
ICAO Annex 14, Volume I, Chapter 8 (electrical systems) and Aerodrome Design Manual, Doc 9157, Part 5. IEC 61822 (constant current regulators) and IEC 61823 (AGL series transformers). FAA AC 150/5340-30 (design and installation of airport visual aids), AC 150/5345-10 (constant current regulators), AC 150/5345-47 (series isolation transformers) and AC 150/5345-7 (L-824 cable). Use the current edition of each.
Quick answers on circuit-by-circuit lighting load and power for the runway, taxiway and whole system.
It works out runway and taxiway lighting load and power, circuit by circuit, from fixture counts and primary cable lengths. For every circuit it adds fixture load, isolating transformer losses and cable I squared R loss, then reports kW and kVA for the runway, the taxiway and the whole airfield lighting system, with a CCR loading check on each circuit.
Use one row per CCR circuit, say whether it serves the runway or the taxiway, and enter the current, the primary cable and the CCR rating. The current is the CCR output at full brightness, normally 6.6 A, so it matches the fixture watts entered. The loop cable is the full series loop, out and back, and you leave it at 0 to ignore cable loss. Then enter the fixture types, quantities and watts for each circuit.
The fixture load is the sum of quantity times watts. The transformer loss comes from dividing the fixture load by the transformer efficiency. The cable loss is the current squared times the loop resistance, corrected for temperature. The circuit total is the transformer-side load plus the cable loss.
The apparent power is the real power divided by the power factor, and the approximate output voltage is that kVA divided by the current. The voltage is an approximation for quick checking and is not a substitute for a voltage drop check. The runway, taxiway and system totals are the sums of the circuits, and the kVA values add in the same way because one power factor is applied to every circuit.
Each circuit's apparent power in kVA is compared with the CCR nameplate rating you selected, which is the conservative reading, since FAA CCRs are rated in kW and IEC 61822 CCRs in kVA. The maximum loading is your project's own design rule, not a standard value. The smallest standard CCR that fits within your loading limit is also shown.
The transformer efficiency of 90 percent is a planning assumption. FAA AC 150/5345-47 minimums are 80 percent for 30/45 W and 65 W, 85 percent for 100 W and 150 W, and 90 percent for 200 W and above, so 90 percent is optimistic for the small sizes. FAA requires at least 0.95 power factor for transformers at rated load, but LED fixtures often differ, so use the measured value. The example fixture watts are placeholders typical of incandescent edge lights.
Runway circuit R1 has 100 fixtures of 45 W at 90 percent efficiency, which is 5,000 W, plus 359 W of cable loss on 4,000 m of #8 AWG. That is 5.36 kW or 5.64 kVA at power factor 0.95, and 75 percent of a 7.5 kVA CCR. Taxiway circuit T1 has 60 fixtures of 30 W, which is 2,000 W plus 269 W of cable loss on 3,000 m, giving 2.27 kW or 2.39 kVA, and 60 percent of a 4 kVA CCR. The system total is 7.63 kW and 8.03 kVA.
The load shown is at the CCR output and not the supply demand, because the CCR's own losses and input power factor are not included. It does not size cable for voltage drop or insulation, model brightness steps, or account for secondary cable, connectors or lamp-out conditions. Stop bars, guard lights, approach lighting and signs go in as fixture rows, as long as you enter their watts. Use Calculators #15 and #36 for cable drop and size, and verify the final design against manufacturer data and the applicable standards.
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