The core electrical failure-mode database for the AGL series circuit and associated electrical connections. Do not classify every lighting outage as a fixture failure — first determine whether the actual failure is in the cable, circuit, connector, termination, insulation, electrical connection, protection system or associated equipment.
Key principle — Do not classify every lighting outage as a fixture failure. First determine whether the actual failure is in the cable, circuit, connector, termination, insulation, electrical connection, protection system, or associated equipment. Every electrical failure record should capture the full failure chain — one electrical failure can lead to another.
Core categories — Cable insulation breakdown, open circuit, short circuit, earth fault, connector failure, high-resistance joint, voltage imbalance and circuit overload are the eight starting electrical-failure categories of Division 02. The remaining twelve topics are expanded diagnostic and failure-intelligence categories, not replacements for the original eight.
Relationship to Division 05 — ELF-01, 02, 03, 04, 05, 09 and 10 (cable insulation breakdown, open circuit, short circuit, earth fault, connector failure, cable termination failure and cable joint failure) are treated here at the general series-circuit/electrical level. For the cable- and connector-hardware-specific version of the same failure modes — physical construction, installation cause and connector-interface detail — see Division 05 — Cable & Connector Failures.
Failure or deterioration of cable insulation resulting in reduced insulation integrity, leakage, earth fault, short circuit or eventual circuit failure.
Complete interruption of the electrical path in the AGL circuit.
Trace the circuit systematically rather than replacing individual fixtures without confirmation.
An open circuit is a failure mode, not necessarily the root cause. For example:
or
Unintended low-resistance electrical connection producing abnormal current flow.
Unintended connection between an energized circuit and earth/ground.
Connector failure is identified as one of the starting electrical-failure categories for Division 02.
For detailed connector-specific failure analysis, cross-reference Division 05 — Cable & Connector Failures.
A connection having abnormally high electrical resistance.
This makes high-resistance joints particularly important for early detection during preventive maintenance.
Abnormal voltage distribution within an electrical system or associated AGL electrical arrangement.
Electrical loading exceeding the intended operating capacity of the circuit or equipment. This is the final category among the eight starting electrical-failure categories.
Check both the electrical integrity and mechanical integrity of the termination.
This is broader than an immediate insulation breakdown.
Record the historical insulation-resistance trend, not just the latest measurement. That allows the database to identify progressive degradation before complete failure.
Unintended current flowing through insulation paths, earth paths or other unintended electrical paths.
Compare leakage/current readings against previous records, normal operating condition, circuit condition and environmental conditions.
Determine whether the poor connection resulted from installation, maintenance, component quality, environmental deterioration, mechanical vibration or ageing.
Terminal connection that has lost the required mechanical/electrical tightness.
A loose terminal can be both failure mode: loose terminal, and root cause: incorrect maintenance torque. The database should keep those fields separate.
Compare:
Incorrect polarity of an electrical connection.
Depending on the equipment involved:
Record expected polarity, actual polarity, test instrument, test result, wiring condition and corrective action.
Failure to maintain a continuous electrical path through the intended circuit.
Perform continuity testing systematically after safe isolation.
Continuity failure describes the test/result condition. The actual root cause could be broken conductor, failed joint, loose connector or incorrect termination.
Electrical fault that appears and disappears rather than remaining continuously present.
Intermittent faults are often difficult to reproduce.
Record the exact operating conditions under which the fault occurred.
Damage resulting from an abnormal transient electrical event.
Record date/time of failure, weather condition, lightning activity if known, equipment affected, protection condition, surge-protection status and number of simultaneously failed components.
If multiple fixtures/components fail simultaneously, investigate whether the event represents a systemic electrical transient rather than individual component failure.
Failure of protective equipment or protective functionality to operate correctly.
A protection failure can convert a relatively small electrical fault into major equipment damage or system outage.
Standard record structure, RCA relationships, classification and evidence layer that apply across all 20 Division 02 electrical-failure topics.
Each electrical failure should preferably be converted into a standard failure record with the following fields:
Division 02 should specifically capture the failure chain, because one electrical failure can lead to another.
These relationships become extremely valuable when Division 02 is later connected to the Root Cause Analysis Database and Reliability & Failure Trend Analysis.
The 20 topics are organised into five logical groups while retaining the original numbering, making the database easier to search without changing the master architecture:
The first eight remain the primary/core electrical-failure categories; the remaining twelve are expanded diagnostic and failure-intelligence categories, not replacements for the original eight.
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
Division 02 links every failure to the Root Cause Analysis Database. The most relevant RCA categories for electrical failures are:
Division 01 captures failures at the fixture level — LED, driver, lamp, optics, housing. Division 02 captures failures in the electrical path feeding those fixtures — cable, circuit, connector, termination, insulation, protection and associated equipment. Before recording a lighting outage in Division 01, first rule out the Division 02 causes covered here: a fixture that appears failed may in fact be starved by an open circuit, an earth fault, or a high-resistance joint upstream.
Quick answers about electrical failures in the AGL series circuit, as covered in Division 02 of the AGL Failure Database.
Division 02 covers the electrical path that feeds AGL fixtures: the series circuit and its associated electrical connections. It contains 20 published topics (ELF-01 to ELF-20) covering cable, circuit, connector, termination, insulation, protection and associated-equipment failures.
Cable insulation breakdown, open circuit, short circuit, earth fault, connector failure, high-resistance joint, voltage imbalance, circuit overload, cable termination failure, cable joint failure, insulation deterioration, leakage current, poor electrical connection, loose terminal, incorrect wiring, polarity error, circuit continuity failure, intermittent electrical fault, electrical surge damage and electrical protection failure.
The first eight topics are the primary, core electrical-failure categories, and the remaining twelve are expanded diagnostic and failure-intelligence categories that do not replace the original eight. The topics are grouped into five logical sets while keeping the original numbering: Cable & Circuit Integrity (8 topics), Connection & Termination (6 topics), and three two-topic groups covering electrical performance, wiring and configuration, and transient and protection.
Division 02 records the full chain because one electrical failure can lead to another. For example, cable ageing leads to insulation deterioration, low insulation resistance, leakage current, an earth fault, a CCR trip and a lighting outage. In a connection chain, a loose terminal leads to high contact resistance, heating, connection deterioration, an intermittent fault and finally an open circuit. Moisture, surge and incorrect-wiring chains are also captured.
Division 01 captures failures at the fixture level, while Division 02 captures failures in the electrical path feeding those fixtures. A fixture that appears failed may in fact be starved by an open circuit, an earth fault or a high-resistance joint upstream, so these Division 02 causes should be ruled out first.
Each electrical failure should become a standard failure record. Fields include failure ID, airport/project, circuit and cable identification, equipment affected, failure date, operating condition, failure category and mode, symptoms, test results, fault location, physical evidence, environmental condition, previous failure history, root and contributing cause, corrective and preventive action, retesting, operational impact, downtime, severity, related SOP, drawing and test report, photographs, lessons learned and recurrence status.
The circuit is isolated safely and insulation-resistance testing is performed. Readings are compared with historical values, and the circuit is segmented where necessary to locate the defective section. The cable is then inspected physically, and joints and terminations are checked. Evidence includes IR test readings, the cable-test report, fault location, cable photographs, maintenance history and environmental conditions.
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).
Division 02 links every failure to the Root Cause Analysis Database. The most relevant RCA categories are Electrical, Thermal, Environmental, Installation, Maintenance, Material, Component and Human/Procedural.
From loose terminations and insulation breakdown to earth faults and voltage drop, electrical failures rarely have a single cause — real troubleshooting means understanding series-circuit behaviour and load characteristics well enough to find the fault, not just the symptom.
Take that knowledge further with Precision AGL Academy.
Learn how to connect:
Develop structured knowledge across AGL fundamentals, components, electrical systems, testing, photometry, troubleshooting, maintenance and commissioning.
Find the failure. Understand the cause. Build the engineering skill.
Please read before relying on any content on this page or on any record downloaded from it.