Turn a circuit route into an order: feeder and return cable, fixture slack, joints, wastage and the number of drums.
A series circuit runs out from the CCR and back to it, so the cable needed is more than the route length. Every fixture takes slack, every drum change or long pull adds a joint, and every drum leaves a few metres on the core. This tool builds the order length line by line, then finds how many drums of your chosen size cover it and how much is left over.
CCR to the start of the lighting field. It is laid out and back, so it counts twice.
Start to end of the fixtures along the outgoing cable.
Each one takes slack for connectors and the transformer pit.
Cable drawn into the pit and left for re-termination.
CCR end, both ends of the loop, including tails to the terminals.
Bends, crossings, trench undulation and pit-to-pit offsets. Your own project figure.
Cut-back and overlap at each straight joint.
Longest length you will pull between pits or joint bays. Set 0 to ignore.
Standard supplier length, such as 250, 500 or 1,000 m. The comparison table on the next tab compares all three.
Left on the core and the inner end. Use the supplier figure.
Each is costed on its own drums.
From the data sheet. Set 0 to skip.
Set 0 to skip.
| Item | Basis | Length (m) |
|---|
| Drum (m) | Drums | Joints | Order (m) | Leftover (m) | Utilisation (%) |
|---|
Every step is shown so the quantity can be checked by hand.
The feeder is laid out and back, the field cable goes out along the route, and the return runs back.
Slack at each fixture and the termination allowance are added, then a routing percentage covers bends and offsets.
Joints come from the drum count, or from the maximum pull if that needs more. Each joint uses a little cable, so the two are solved together until the joint count stops changing.
Leftover is the usable cable on the drums less the order length. Drums for several circuits are counted per circuit, with the shared-offcut count shown for comparison.
| Item | Value |
|---|---|
| Feeder 500 m, field 2,400 m, same return | 5,800 m |
| 100 fixtures × 1.5 m + 20 m | + 170 m |
| Routing 5 % | 6,268.5 m |
| 500 m drums, 5 m unusable | 495 m usable |
| 13 joints × 1 m, wastage 3 % | 6,469.9 m |
| Drums required | 14 |
| Leftover | 460.1 m |
| Utilisation | 92.4 % |
It does not plan cut lengths between pits, pick drum lengths to match them, or allow for different cable types in one circuit. Percent allowances are project assumptions, and drum lengths and unusable cable come from your supplier.
Quick answers on how the cable order length, joints and number of drums are worked out.
It turns a circuit route into a cable order. It builds the order length line by line from the feeder and return cable, fixture slack, termination allowance, routing allowance, joints and wastage, then finds how many drums of your chosen size cover it and how much is left over. It also compares 250 m, 500 m and 1,000 m drums and produces a PDF report.
The feeder is laid out and back, so Lbase = 2 × feeder + field + return. Slack at each fixture and the termination allowance are added, then a routing percentage covers bends, crossings, trench undulation and offsets: Lr = (Lbase + n × slack + terminations) × (1 + routing %).
Joints come from the drum count, or from the maximum pull if that needs more, so Joints = max(drums − 1, ⌈Lr ÷ max pull⌉ − 1). Each joint uses a little cable, so the two are solved together until the joint count stops changing. The order length is Lorder = (Lr + joints × per-joint) × (1 + wastage %).
Drums = ⌈Lorder ÷ (drum length − unusable)⌉, where the unusable cable per drum is the length left on the core and the inner end, from your supplier. Leftover is the usable cable on the drums less the order length, and utilisation is the order length divided by the drum length supplied. Drums for several circuits are counted per circuit, with the shared-offcut count shown for comparison.
With a 500 m feeder, a 2,400 m field route and the same return, the base length is 5,800 m. Adding 100 fixtures × 1.5 m plus 20 m (170 m) and 5 % routing gives 6,268.5 m. With 500 m drums, 5 m unusable, 13 joints at 1 m each and 3 % wastage, the order length is 6,469.9 m, which needs 14 drums, leaves 460.1 m and gives 92.4 % utilisation.
No. The percentage allowances are project assumptions, and the slack, termination, per-joint and unusable cable values are your own figures. Drum lengths and unusable cable come from your supplier. The cable weight and price fields are optional and can be set to 0 to skip them.
It does not plan cut lengths between pits, pick drum lengths to match them, or allow for different cable types in one circuit. It assumes one continuous run per circuit with a straight joint at each drum change. Order against the final cable schedule and the supplier's available drum lengths.
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