What is cable routing?
Laying AGL cable along the route the design shows — a prepared trench and clean bed, gentle bends, slack at pits and joints, cover and warning tape above, and the final route recorded as-built.
Cable routing is laying the primary and secondary cables along the route the design shows, between pits, joints, transformers and fixtures. The cable goes on a clean bed at the design depth, with gentle bends, slack at pits and joints, a protective cover and warning tape above, and the final route recorded as-built.
A cable that is bent too tightly, pulled tight or laid on sharp stones can look fine on the day and then fail weeks or months later as an insulation or earth fault that is hard to find and expensive to dig out. Follow the manufacturer's minimum bending radius, keep the cable off sharp edges and test it as the commissioning procedure requires before backfilling. Locate existing services before digging, treat any cable as live until the circuit has been isolated, locked out and proved dead, keep debris off the airfield surface and work to the airport's permit-to-work.
- Route. Set out the run from the design and as-builts, clear of existing services.
- Trench and bed. Excavate to the design depth and width and form a clean bed.
- Lay. Lay the cable without dragging it over edges or twisting it.
- Form the bends. Keep every bend gentle and above the minimum bending radius.
- Leave slack. Form gentle loops at pits and joints so no cable is pulled tight.
- Cover, mark and record. Place cover and tape, test as required, then record the route as-built.
Frequently Asked Questions
Q1What is cable routing in AGL installation?
Cable routing is laying the primary and secondary cables along the route the design shows, between pits, joints, transformers and fixtures. The route, depth, bedding, bends, slack and protection are all set by the design, and the final route is recorded as-built.
Q2Why follow the designed route instead of the shortest path?
The route is chosen to keep clear of existing services, pavements and future work, to keep each circuit's cables together and identifiable, and to leave access to joints and pits. A cable taken on its own path is hard to find, easy to damage later and may not match the records.
Q3Why does bending radius matter when routing cable?
Bending a cable tighter than its minimum bending radius can damage the insulation and sheath, often without any immediate sign. The damage can show up later as insulation or earth faults. Use gentle bends and follow the cable manufacturer's minimum bending radius.
Q4Why leave slack in the cable?
Slack in gentle loops at pits, joints and transformers absorbs ground movement and frost and allows a connection to be re-made later without needing a new length of cable. A cable pulled tight puts constant strain on its connections.
Q5How is a buried cable protected?
As the design specifies, usually a bed of suitable fill, a cover or protective layer above the cable, and a warning tape higher up so a later excavation meets the warning before the cable. Backfill must be free of sharp stones and debris that could damage the cable.
Q6What should be checked before the trench is backfilled?
Check the route and depth against the design, a clean bed free of sharp objects, gentle bends, slack at pits and joints, cable ends protected from water, cover and tape in place, and the cable tested as the commissioning procedure requires. Record the as-built route. Locate existing services first, treat any cable as live until proved dead and work to the permit-to-work.
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