The dedicated failure-classification section for AGL earthing, bonding, earth-electrode and lightning/surge-protection infrastructure — covering failures from the main earth network through individual AGL assets, including fixtures, isolating transformers, airfield signs, CCRs, panels and earth pits. Do not record an earthing or bonding fault simply as “earth fault.” Identify the failure mode, electrical condition, physical evidence, probable cause, root cause, corrective action and recurrence risk.
Key principle — An earthing or bonding failure should be recorded separately from the equipment failure that it causes. For example: loose earth connection → poor bonding → high earth resistance/earth continuity problem → equipment safety risk. Every record should answer: what failed → how did it fail → why did it fail → what evidence confirmed it → how was it corrected → how can recurrence be prevented?
Measured earth resistance is higher than the applicable design, project, maintenance or acceptance requirement.
The required electrical continuity of the earthing conductor/bonding path is not maintained.
Verify continuity from the relevant equipment to the designated earthing point/network.
Physical or electrical discontinuity of an earth conductor.
Earth conductor or bonding connection is not securely connected to its designated termination.
Inspect, clean where appropriate, correctly secure and verify the connection according to the applicable procedure/specification.
Corrosion has degraded an earth/bonding connection sufficiently to affect its electrical or mechanical integrity.
Bonding between conductive components/equipment is inadequate to maintain the intended equipotential and electrical connection.
A required bonding connection is absent.
Compare the installed bonding arrangement against the approved design/installation requirement.
Missing bonding connection is the failure mode. Poor bonding is the condition resulting from inadequate bonding.
Failure or absence of the required bonding connection associated with an AGL light fixture.
Cross-reference with Division 01 — Lighting Fixture Failures.
Failure of the required bonding arrangement associated with an isolation transformer or transformer installation.
Verify the intended bonding path and its continuity.
Cross-reference with Division 04 — Isolation Transformer Failures.
Failure of the required bonding arrangement associated with an illuminated airfield sign and its supporting/electrical components.
Cross-reference with Division 12 — Airfield Sign Failures.
Failure of the required earthing arrangement associated with a Constant Current Regulator.
Cross-reference with Division 03 — CCR Failures.
Failure of the earthing arrangement associated with an electrical/control panel.
Check: Panel body → earth terminal → earth conductor → earth network.
Cross-reference with Division 02 — Electrical Failures.
Deterioration of the earth pit or associated components affecting the integrity or accessibility of the earthing system.
Deterioration of the earth electrode resulting in degradation of the earthing system.
Earth-electrode resistance should be trended over time, rather than relying only on a single measurement.
Failure or degradation of the lightning-protection arrangement associated with the AGL installation.
Failure or degradation of surge-protection equipment or its associated earthing/bonding path.
A surge-protection device should not be assessed independently of its earthing and bonding path.
Earthing system has been installed in a manner that does not conform to the approved design, applicable specification or installation procedure.
Compare: Approved design → installation → inspection/testing records → measured results.
An electrical earth fault or abnormal condition is associated with inadequate or defective bonding.
Determine: fault location, bonding condition, earth continuity, conductor condition, connection resistance, equipment affected, root cause.
Do not record only “earth fault.” Where evidence establishes defective bonding as the underlying mechanism, record “earth fault due to poor bonding” and identify the specific bonding failure separately.
Standard record structure, failure-chain relationships, diagnostic matrix, asset-based tracing, RCA linkage, evidence layer and severity scheme that apply across all 18 Division 15 failure topics.
The Division allows failures to be traced to individual AGL assets, from the main earth network through to the individual bonding point:
This asset-based approach makes the failure database useful for inspection, troubleshooting, maintenance and reliability analysis.
Every Division 15 failure should ideally be converted into a standard failure record with the following fields:
Asset Identification
Electrical Condition
Physical Condition
Protection
Installation
RCA
Corrective Action
Verification & Reliability
Division 15 becomes much more valuable when the database captures relationships between failure modes rather than treating each as isolated.
| Failure | Primary Investigation |
|---|---|
| High earth resistance | Earth resistance measurement/trend |
| Earth continuity failure | Continuity path |
| Broken earth conductor | Conductor condition |
| Loose earth connection | Connection integrity |
| Corroded earth connection | Corrosion/contact condition |
| Poor bonding | Bonding integrity |
| Missing bonding connection | Design vs installed bond |
| Fixture bonding failure | Fixture bond/continuity |
| Transformer bonding failure | Transformer bond/continuity |
| Sign bonding failure | Sign bond/continuity |
| CCR earth failure | CCR earth path |
| Panel earth failure | Panel earth path |
| Earth-pit deterioration | Pit/connection condition |
| Earth-electrode deterioration | Electrode condition/resistance |
| Lightning-protection failure | Lightning/bonding network |
| Surge-protection failure | SPD + earth path |
| Incorrect earthing installation | Design/installation verification |
| Earth fault due to poor bonding | Fault + bonding RCA |
Division 15 links every failure to the Root Cause Analysis Database. The most relevant RCA categories for earthing and bonding failures are:
Every failure receives a severity classification, plus operational-impact tagging:
Critical / Safety-Critical — immediate operational or safety risk
Major / Operationally Critical — significant availability impact
Moderate — reduced performance, not yet critical
Minor / Non-Critical — limited or no operational effect
Degradation / Intermittent / Latent — developing or hidden fault
Visual evidence
Technical evidence
Every earthing/bonding failure should eventually become engineering intelligence:
For example: High earth resistance reading → traced to electrode deterioration → corrosion of electrode connection → environmental exposure → electrode repair/replacement → review protective treatment → post-repair earth resistance test.
The Troubleshooting Atlas answers “I have a fault now — how do I diagnose and fix it?” The Failure Database answers “this failure happened — what happened, why, what evidence proves it, what was done, and how do we stop it recurring?” Kept strictly separate, then linked end-to-end, the two form a genuine AGL Failure Intelligence Engine rather than a simple fault list. Division 15 connects directly with Division 01 Lighting Fixture Failures, Division 02 Electrical Failures, Division 03 CCR Failures, Division 04 Isolation Transformer Failures, Division 12 Airfield Sign Failures, Division 18 Maintenance-Induced Failures, Division 19 Product & Component Reliability, Division 21 RCA and Division 23 Reliability Trend Analysis.
Quick answers about AGL earthing, bonding and surge-protection failures, as covered in Division 15 of the AGL Failure Database.
Division 15 covers AGL earthing, bonding, earth-electrode and lightning or surge-protection failures. It contains 18 published topics (EBF-01 to EBF-18), including high earth resistance, earth continuity failure, broken earth conductor, poor bonding and lightning and surge protection failure.
High earth resistance, earth continuity failure, broken earth conductor, loose earth connection, corroded earth connection, poor bonding, missing bonding connection, fixture, transformer and sign bonding failure, CCR earth failure, panel earth failure, earth-pit and earth-electrode deterioration, lightning-protection failure, surge-protection failure, incorrect earthing installation and earth fault due to poor bonding.
They fall into six groups: Earth Electrical Performance (2 topics), Earth Conductor & Connection Failures (5), Equipment Bonding Failures (5), Earth-Pit & Electrode Failures (2), Lightning & Surge Protection (2) and Installation & Consequential Failures (2).
Division 15 lets failures be traced from the main earth network to the individual bonding point. Traces run from a runway or taxiway fixture through its bonding conductor, from an isolation transformer enclosure earth point, from an airfield sign structure bond, from a CCR enclosure earth terminal and from a panel body earth terminal, each back to the earth network, and finally from the earth connection and electrode to the surrounding earth.
In the connection chain, a loose earth connection leads to poor bonding, earth continuity degradation and degradation of the protection or safety path. In the corrosion chain, moisture or salt exposure leads to a corroded earth connection, increased resistance, high earth resistance and earthing-system degradation.
The diagnostic matrix assigns a primary investigation to each topic. High earth resistance starts with earth-resistance measurement and trend, earth continuity failure with the continuity path, broken earth conductor with conductor condition, loose earth connection with connection integrity, corroded earth connection with corrosion and contact condition, poor bonding with bonding integrity, and missing bonding connection with design versus installed bond.
Every failure follows a loop: failure event, failure mode, failure mechanism, root cause, corrective action, preventive action and post-repair test. For example, a high earth-resistance reading is traced to electrode deterioration, then to corrosion of the electrode connection caused by environmental exposure, leading to electrode repair or replacement.
Every failure receives a severity classification, plus operational-impact tagging. The classes are Critical / Safety-Critical (immediate operational or safety risk), Major / Operationally Critical (significant availability impact), Moderate (reduced performance, not yet critical), Minor / Non-Critical (limited or no operational effect), and Degradation / Intermittent / Latent (a developing or hidden fault).
The Troubleshooting Atlas answers “I have a fault now — how do I diagnose and fix it?” The Failure Database answers “this failure happened — what happened, why, what evidence proves it, what was done, and how do we stop it recurring?” Kept strictly separate, then linked end to end, the two form an AGL Failure Intelligence Engine rather than a simple fault list.
A high resistance reading can come from a corroded electrode, a broken bonding connection, soil conditions or a design gap — real troubleshooting means understanding the earthing and bonding system well enough to trace the reading back to its cause.
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