What is fixture installation?

Fitting the light to its base can or mounting — a clean, drained base, a new seal, the secondary connector made and sealed, the fixture seated at the design level and bolted to the specified torque, then tested before the area is handed back.

INSET FIXTURE · SECTIONbase can, seal, bolts, sealed lead ELEVATED FIXTURE · ELEVATIONfrangible coupling, design height PAVEMENT BOLTS FIXTURE GASKET / O-RING CONNECTOR SLACK LEAD DRAINED BASE GROUND BASE CAN DESIGNHEIGHT FIXTURE HEAD MAST FRANGIBLE COUPLING BREAK POINT SIX INSTALLATION CHECKS · IN ORDER 1 ISOLATElock out, prove dead 2 PREPAREclean base, new seal 3 CONNECTsealed, with slack 4 SEATlevel, at design height 5 TORQUEcalibrated, as specified 6 TESTlight, record, no FOD
seal, bolts and frangible coupling
fixture and secondary lead
design height
pavement and base can
The Fact Installation & construction

Fixture installation is fitting the light fixture to its base can, stake or other mounting and connecting it to the secondary lead from the isolating transformer. The base is cleaned and checked first, the secondary connector is made and sealed, the fixture is seated on a new seal at the design level, and its bolts are torqued to the specified value before the light is tested.

A fixture sits at the surface of the airfield, so mistakes show quickly. A poor seal lets water into the can and onto the connector, and a loose or badly seated fixture can shift under traffic or come loose onto an operational surface. An elevated fixture must stay frangible, with its coupling at the designed break point. Leave slack on the lead, take no shortcuts with the torque, and clear every tool and scrap away. Treat the leads as live until the circuit has been isolated, locked out and proved dead, and work to the airport’s permit-to-work.

  1. Isolate. Switch off, lock out and prove the circuit dead before any work.
  2. Prepare. Clean and drain the base, check the flange and fit the specified new seal.
  3. Connect. Make and seal the secondary connector and leave a slack loop in the can.
  4. Seat. Lower the fixture squarely onto the seal at the design level, without trapping the lead.
  5. Fix and torque. Fit the bolts as specified and tighten with a calibrated torque wrench.
  6. Test, clear and record. Check insulation resistance and discharge the circuit afterwards, re-energise under the permit, confirm the light works, remove all tools and debris and log the fixture.
Purpose Fix the light securely to its mounting, sealed and connected to the secondary lead
Base Clean, drained, flange undamaged, at the design level
Seal New gasket or O-ring as the manufacturer specifies, on clean faces
Fixing Specified bolts and torque, with a calibrated tool
Elevated fixtures Frangible coupling intact at its break point, at the design height
Reference FAA AC 150/5340-30 · AC 150/5345-46 · AC 150/5370-2 · AC 150/5370-10 (Item L-125) · ICAO Doc 9157 Pts 4 and 5
Schematic — simplified and not to scale. Fixture type, seal, bolting, torque and mounting height depend on the manufacturer and the design; follow the design drawings, the manufacturer’s installation data and your site’s permit-to-work and torque-checking procedures.
Entry 14 · Connector sealing Entry 16 · Fixture alignment

Frequently Asked Questions

Q1What is fixture installation in AGL?

Fitting the light fixture to its base can, stake or other mounting and connecting it to the secondary lead from the isolating transformer. It covers preparing the base, making and sealing the connector, seating the fixture at the design level, fixing and torquing it, and testing the light.

Q2Why is a new gasket or O-ring fitted each time?

The seal keeps water out of the fixture and base can, and it takes a set once compressed. A reused or damaged seal is a common cause of water ingress and earth faults. Fit the seal the manufacturer specifies, on clean faces, and do not use unapproved sealant in its place.

Q3Why must the bolts be torqued to a specified value?

Too loose, and the fixture can leak, shift or work loose under traffic and vibration. Too tight, and bolts, threads, flange or fixture can be damaged. Use a calibrated torque wrench, the bolt type and the sequence the manufacturer specifies, and check the result afterwards.

Q4What is different about installing an elevated fixture?

Elevated fixtures sit above the surface, so they must be frangible: they break away cleanly on impact. Keep the frangible coupling at its designed break point, mount the fixture at the design height and do not strengthen or modify the coupling. See Frangible Mounting.

Q5What should be done before leaving the fixture?

Check insulation resistance (discharging the circuit afterwards) and that the light operates as the commissioning procedure requires, confirm the fixture is seated, tightened and clean, remove all tools and debris so nothing is left on the airfield surface, and record the fixture, its position and the work. Work only on an isolated, locked-out circuit that has been proved dead.

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