What is earthing installation?
Putting in the earth that waits for the day something fails — a conductor laid with the cable, rods and pits, sound joints, equipment bonded to it, and the resistance measured and recorded.
Earthing installation is laying and connecting the system that gives fault and lightning current a low-resistance path to earth. A bare conductor (the counterpoise) is laid with the cable, ground rods are driven at the designed positions with earth pits and test links, the joints are made, and the metalwork of fixtures, base cans and signs is bonded to it as the design requires.
Earthing does nothing until something fails, so a poor job stays hidden. A joint that corrodes, a conductor cut by later digging or a rod that never reached good soil can leave metalwork live with no safe path for the fault current. Make joints as the design specifies and protect them, keep the earthing system apart from the insulated series-circuit conductors, and measure the result before handing over. That first reading is the baseline for earthing maintenance. Work on circuit equipment only when it has been isolated, locked out and proved dead.
- Isolate. Switch off, lock out and prove the circuit dead before working on any equipment connection.
- Lay the conductor. Run it with the cable at the designed cover, with warning tape above and clean backfill around.
- Drive the rods. Install ground rods and earth pits at the designed positions.
- Make the joints. Join conductor, rod and test link as specified, then protect each joint.
- Bond the metalwork. Connect fixtures, base cans, signs and other metalwork as the design shows.
- Measure and record. Test the earth resistance, record it with the as-built drawings and close the pits.
Frequently Asked Questions
Q1What is earthing installation in AGL?
Laying and connecting the earthing system that gives fault and lightning current a low-resistance path to ground. It covers the earthing conductor, the ground rods and earth pits, the joints between them, the bonding of equipment metalwork, and measuring the result.
Q2Why is the earthing conductor laid with the cable?
Fault and lightning currents can flow along the cable route, so the conductor runs where it is needed and ties the equipment along that route to the same earth. Its position and cover are set by the design, and it is laid so later digging is less likely to cut it.
Q3How are earthing joints made?
Make joints the way the design and the manufacturer specify, usually by welding or approved compression connectors on clean metal. Protect each joint against corrosion, because a buried joint that corrodes can fail without any sign. A poor joint can leave an item with no effective earth.
Q4Why must the series circuit conductors stay insulated from earth?
The series circuit is insulated from earth by design, so an unintended earth connection on it is a fault. Keep the earthing conductor, rods and bonds apart from the circuit conductors, and never leave an earth connected to a series-circuit conductor. Temporary safety earths are applied only to an isolated circuit, under the permit, and removed before energising. Work on circuit equipment only when it is isolated, locked out and proved dead.
Q5Why is the earth resistance measured after installation?
The first reading shows whether the rods and joints do their job and becomes the baseline for later checks. Open the test link in the earth pit as the procedure requires, measure with an earth tester, and record the reading with the as-built drawings. Soil resistance varies with the weather, so compare like with like.
See It. Understand It. Then Learn How to Engineer It.
Recognising an AGL system visually is the first step. The next step is knowing how to design, install, test, commission and maintain them correctly.
Build Practical AGL Engineering Skills
Go deeper with structured training from Precision AGL Academy, covering:
Learn how each light, sign and circuit works as part of a complete airport lighting system, not just as an isolated diagram.