What is a cable trench?
The excavated route that carries AGL cable across the airfield. How it is dug, bedded and backfilled decides whether the cable stays protected for decades.
A cable trench is an excavated route in which AGL cable is laid, directly or in duct. It is filled in layers: bedding around the cable, a protective cover where required, warning tape above, then compacted backfill and surface reinstatement.
It is a civil interface because it is excavated and reinstated with the civil works, often beside pavement, drains and other services. The route, depth, width, bedding, crossings and reinstatement must be agreed with the civil team, and chambers such as handholes sit at turns and long pulls.
The excavation and its layered fill. Can hold direct-buried cable or ducts.
Ducts, often concrete-encased, laid in a trench so cable can be replaced without re-excavating.
Frequently Asked Questions
Q1What is a cable trench in airfield ground lighting?
An excavated route in the ground in which AGL cable is laid, either directly or in duct. It is backfilled in layers, with bedding around the cable and warning tape above, so the cable is protected and can be located later.
Q2Why is a cable trench a civil interface?
It is excavated, bedded and backfilled as part of the civil works, often beside pavement and other services. Route, depth, width, bedding, crossings and reinstatement must be agreed with the civil team.
Q3How is a trench different from a duct bank?
A trench is the excavation. A duct bank is the set of ducts, often concrete-encased, laid in it. A trench can carry direct-buried cable or ducts, and a duct bank lets cable be replaced without re-excavating.
Q4What goes in a typical trench cross-section?
Bedding material such as sand under and around the cable, a protective cover where required, warning tape above, then compacted backfill and the surface reinstatement, all at depths set by the project specification.
Q5What matters at crossings and bends?
Where trenches cross pavement, drains or other services, the civil design sets the method and clearances. Cable keeps its minimum bend radius, and chambers such as handholes are placed at turns and long pulls.
Q6Where are the requirements defined?
FAA AC 150/5370-10 and AC 150/5345-42 cover related items, and ICAO Aerodrome Design Manual Part 5 covers electrical systems. Confirm against the current edition and project specifications.
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