AGL Handhole

A handhole is an accessible underground cable-routing and maintenance point within an airfield lighting installation. It supports organised cable management and gives practical access for inspection, cable jointing, testing and maintenance without extensive excavation of the surrounding airfield infrastructure.

Typical locations are cable crossings and route transitions, branch cable routes and circuit distribution points, maintenance and inspection locations, cable jointing and connection points, interfaces between cable ducts, conduits and field equipment, and any location that needs an accessible underground service point.

Cover loading is selected according to the installation location and the applicable loading requirements. A cover in an area trafficked by aircraft must carry the design aircraft wheel loading and sit flush with the surrounding pavement. State the load class on the order (for example EN 124 classes, where Class F 900 is intended for aircraft pavements, or the applicable Indian Standard) and confirm it against the design aircraft load. In the runway strip and other graded areas the cover must be flush with the surrounding grade so it does not become an obstacle.

Handhole dimensions are project and cable-routing dependent, and installation depth is determined by the cable routing, duct arrangement and site requirements. Cable capacity is selected according to the number and size of cables. Final dimensions should consider not only cable capacity but also the access needed by installation and maintenance personnel, with enough internal working space where joints or connections sit inside the handhole.

Cable entries are arranged for controlled routing into and out of the handhole, and may include multiple cable or duct entries where circuits branch or change direction. Routing should maintain suitable bend radii and prevent excessive mechanical stress on primary and secondary cables. Unused entries should be sealed or protected as required by the installation design.

Handholes can be integrated with underground cable duct systems to provide accessible points along longer cable routes. Duct entries should be aligned with the handhole and securely terminated to prevent damage to cables during installation or later maintenance, and the transition should maintain suitable mechanical protection and cable support.

Drainage should prevent standing water accumulating inside the handhole. The right arrangement depends on the ground conditions, water table, pavement construction and site drainage system, and it may be coordinated with the surrounding sub-base or a dedicated drainage arrangement. Standing water is also a safety issue: wet joints and connectors raise the risk of insulation failure and shock, so water should be pumped out before work.

Check cover seating and accessibility, the cable and duct entry arrangement, cable routing and bend radius, secure cable positioning, drainage provisions, protection of cable joints and connectors, the finished level relative to the surrounding installation, and that cable and circuit identification labels are in place. Record the as-built position and level, and inspect and test any joints or connections inside the handhole under the project commissioning procedure.

Yes. Handholes can be used when upgrading or rehabilitating existing airfield lighting cable networks, with replacement configurations selected for revised cable quantities, new duct routes or changes to the electrical distribution arrangement. Where an existing handhole is being replaced, assess the surrounding pavement, drainage and cable infrastructure first to determine the right replacement configuration.

No. An open series circuit driven by a constant-current regulator can produce dangerously high voltage, and opening, cutting or disconnecting any part of an energised circuit can cause serious injury or death. De-energise the circuit at the regulator, apply the site lock-out / tag-out procedure, use the series circuit cut-out switch or an approved isolation device, and verify the circuit is de-energised before touching conductors, connectors or splices. See the electrical safety warning on this page.

Principal references are FAA AC 150/5370-10 (Item L-110 for underground electrical ducts and conduits and Item L-108 for underground cable for airports), FAA AC 150/5340-30J, ICAO Doc 9157 Aerodrome Design Manual Part 5 (Electrical Systems), and DGCA India CAR Section 4 with airport specifications. Selection and installation should also be coordinated with the airfield lighting design, pavement loading requirements and local project specifications.

Confirm the dimensions, materials, cover loading, drainage and cable-entry arrangements against the requirements of the specific installation before procurement. The cable quantity and size, routing directions, available installation space, access requirements, and the surrounding pavement, verge or underground service conditions all feed into the configuration.