AGL Diagrams Schematic, Single-Line & Wiring Diagrams
Learn how airfield lighting diagrams show the connections between CCRs, series circuits, isolating transformers, light fittings and ALCMS control, and how to read them without mistaking a typical diagram for an approved project drawing.
What Are AGL Diagrams?
Airfield Ground Lighting (AGL) diagrams explain how electrical equipment, control systems, cables, transformers and light fittings are interconnected. They help engineers understand system architecture, interpret technical drawings, prepare project documentation, plan installations and troubleshoot electrical or control-system faults.
AGL diagrams are used throughout the engineering lifecycle, including design, procurement, installation, testing, commissioning, operation and maintenance. Depending on the drawing type, they may show the overall electrical distribution arrangement, individual series circuits, equipment connections, control interfaces or installation details.
Drawing types covered on this page
Airfield Lighting System Diagram
An Airfield Ground Lighting system diagram provides an overview of the main equipment and the relationship between electrical supply, regulation equipment, series circuits and airfield light fittings.
A typical AGL series circuit may include
- — Constant Current Regulator (CCR).
- — Primary series cables.
- — Primary cable connectors and joints.
- — Airfield Ground Lighting isolating transformers.
- — Secondary connectors and leads.
- — Runway, taxiway or approach light fittings.
- — Control and monitoring interfaces, where applicable.
The CCR supplies the series circuit at the specified operating current within its design limits. Isolating transformers provide electrical separation between the primary series circuit and the secondary circuit supplying individual light fittings.
The actual arrangement depends on the approved electrical design, circuit configuration, equipment ratings and manufacturer requirements.
Engineering application: Use the system diagram to understand the relationship between equipment, identify major components and trace the general path of power from the supply equipment to the field lighting loads.
Control on top, power chain below, lights at the bottom.
AGL Visual Encyclopedia: Complete AGL system architecture Series-circuit architecture CCR system overview
AGL Single-Line Diagram
An AGL single-line diagram presents the main electrical distribution arrangement in a simplified format. It helps engineers understand how power distribution equipment, CCRs and lighting circuits are arranged within an airport lighting installation.
A typical single-line diagram may show
Incoming electrical supply and distribution equipment.
Distribution boards and associated protective devices.
CCRs and their assigned series circuits.
Runway, taxiway and approach lighting loads.
Circuit names, numbers and equipment tags.
Switching, isolation and control arrangements.
Relevant earthing and protective arrangements.
Interfaces with the AGL control and monitoring system.
The drawing legend and circuit schedule are essential for interpreting the symbols, identifiers and connections correctly.
Engineering application: Single-line diagrams support design reviews, circuit identification, equipment schedules, maintenance planning and coordination between electrical, control and installation teams.
Single-line diagram of an airfield substation.
AGL Visual Encyclopedia: Airfield substation single-line diagram Dual feeders Standby power and UPS
AGL Series Circuit Diagram
An AGL series circuit diagram explains the general connection between a CCR, primary series cables, isolating transformers and individual light fittings.
Simplified AGL series circuit (educational representation)
This is a simplified educational representation. The actual circuit may contain multiple transformers and light fittings connected in a series-circuit arrangement, with the configuration determined by the approved design.
The primary circuit and the secondary connections serve different purposes. The primary circuit carries the regulated series current through the circuit components, while the transformer secondary supplies its associated light fitting.
Key components
Constant Current Regulator (CCR)
Supplies regulated current to the AGL series circuit according to its design and operating requirements.
Primary series cable
Connects the series-circuit equipment and carries current through the circuit.
Isolating transformer
Provides electrical separation between the primary circuit and the associated secondary lighting load.
Secondary connector and lead
Connects the transformer secondary to the light fitting using the specified connector arrangement.
Airfield light fitting
Produces the required visual guidance for the applicable runway, taxiway or approach lighting application.
Engineering application: Use the series-circuit diagram to understand system operation, identify components and support fault investigation alongside approved circuit drawings and test procedures.
Related Guides
CCR working principle AGL isolating transformers AGL cables & connector engineeringThe current path round a series loop.
AGL Visual Encyclopedia: Series-circuit current path Series-circuit architecture Series-circuit principle
CCR Wiring Diagram
A Constant Current Regulator wiring diagram describes the electrical connections and control interfaces associated with a specific CCR model.
Depending on the equipment, the manufacturer’s schematic may identify
Incoming power connections.
Main switching and protective components.
Power regulation circuitry.
Current sensing and feedback.
Local and remote control interfaces.
Intensity-step selection and command inputs.
Status indications and monitoring signals.
Alarm outputs and communication interfaces.
Protective interlocks and equipment-specific terminals.
CCR wiring differs between manufacturers, models, ratings and control arrangements. Terminal designations, wiring colours, protection devices and control logic must be confirmed from the relevant manufacturer’s documentation.
Main power path and the blocks that support it.
AGL Visual Encyclopedia: CCR system overview CCR internal architecture CCR control architecture
AGL Isolating Transformer Diagram
An AGL isolating transformer diagram identifies the transformer’s primary and secondary sides and explains its connection to the primary series circuit and secondary light fitting.
A technical drawing or product diagram may identify
Information to verify during selection
Before selecting or replacing an isolating transformer, confirm:
Required wattage and application.
Primary and secondary current ratings.
System frequency and relevant electrical ratings.
Connector types and cable compatibility.
Installation environment and environmental protection requirements.
Applicable project specifications and product compliance requirements.
Plug-in unit and its connectors in a pit.
AGL Visual Encyclopedia: Plug-in isolation transformers Isolation transformer principle Secondary winding
AGL Cable, Connector and Secondary Wiring Diagrams
Cable and connector diagrams show how the primary series cable, connector assemblies, transformer leads and secondary connections are arranged.
The drawing may include
Primary cable routing and circuit identificationCable joint and termination detailsPrimary connector assembliesConnector plug and receptacle arrangementsSecondary lead connectionsCable identification and labellingRelevant installation and inspection detailsCable sizes, connector compatibility, termination methods and installation requirements must be confirmed against the approved design and equipment documentation.
Engineering application: These drawings assist with cable installation, component identification, maintenance planning, inspection and troubleshooting.
Where connectors and joints sit on a circuit.
AGL Visual Encyclopedia: Connector locations Primary connector Secondary connector
Secondary cable in cross-section and in use.
AGL Visual Encyclopedia: Secondary cable Cable identification Cable joint
Runway, Taxiway and Approach Lighting Diagrams
AGL layout drawings show the position and arrangement of lighting equipment in relation to the runway, taxiway, approach area or other designated airfield areas. Depending on the application, the drawings may cover:
Runway lighting
- Runway edge lights.
- Runway threshold and runway-end lights.
- Runway centreline lights.
- Touchdown zone lights.
- Runway guard lights, where applicable.
- Associated circuit identification and equipment references.
Taxiway lighting
- Taxiway edge lights.
- Taxiway centreline lights.
- Stop bars and runway guard lights, where applicable.
- Taxiway junctions and intersections.
- Associated circuit and control references.
Approach lighting
- Approach lighting system layout.
- Light bars and longitudinal rows.
- Crossbars and associated components.
- Circuit allocation and equipment identification.
- Relevant interfaces with other visual guidance systems.
The actual layout depends on the applicable aerodrome requirements, approved design, runway category, system configuration and project-specific documentation.
Runway lighting plan.
AGL Visual Encyclopedia: Runway lighting layout Runway edge lights Threshold lights
Taxiway lighting plan.
AGL Visual Encyclopedia: Taxiway lighting layout Complete taxiway lighting system Taxiway centreline lights
Three approach light layouts compared.
AGL Visual Encyclopedia: Approach light layout Approach lighting system overview Centreline approach lights
ALCMS Architecture and Wiring Diagrams
An Airfield Lighting Control and Monitoring System (ALCMS) diagram explains how operator interfaces, control equipment, CCRs, field circuits and monitoring systems interact.
A typical architecture drawing may show
Air traffic control or operator workstation interfaces.
AGL control equipment and system controllers.
CCR command and status interfaces.
Field lighting circuit references.
Monitoring signals and equipment status.
Communication networks and interface devices.
Alarm indications and event monitoring.
Project-specific interlocks and dependencies.
Control commands versus monitoring indications
Control commands
Requests to operate or change a lighting function, subject to the system’s design and authorization arrangements.
Monitoring indications
Reported equipment status, circuit conditions or alarm information available to the control system.
These functions should be identified separately on the drawing. The exact command, feedback, interlock and communication arrangements must follow the approved ALCMS architecture and manufacturer documentation.
Control positions, servers, networks and field controllers.
AGL Visual Encyclopedia: ALCMS communication architecture AGL control system architecture ALCMS failure flow
AGL CAD Drawings and Installation Details
Computer-Aided Design (CAD) drawings provide a structured way to prepare, review and maintain AGL engineering documentation.
An AGL drawing package may include
Each drawing should have a suitable title, drawing number, revision, date, units, legend and applicable notes. Where required, it should also identify the project, equipment references, design status and approval information.
Whole-airport layout with the lighting overlaid.
AGL Visual Encyclopedia: Whole airport layout map Complete AGL airport layout Requirement mapping
Installation in six steps, ground to pavement.
AGL Visual Encyclopedia: Installation sequence Installation quality checkpoints Cable routing
How to Read an AGL Diagram
Use the following sequence when studying an AGL engineering drawing:
Check the drawing title.
Identify whether it is a layout, single-line diagram, schematic, wiring diagram or installation detail.
Check the revision and status.
Confirm that the document is current and approved for its intended use.
Read the legend.
Understand the symbols, abbreviations, line types and equipment tags.
Identify the circuit or system.
Locate the CCR, circuit number, field lighting system or control interface relevant to the task.
Trace the connections.
Follow the documented electrical or signal path without assuming that unlabelled lines represent the same type of connection.
Cross-check equipment references.
Compare drawing tags with equipment schedules, data sheets and manufacturer documentation.
Review associated drawings.
Use the circuit schedule, layout, wiring diagram and installation details together where necessary.
Confirm the document status.
Use the approved project documentation and applicable safety procedures before undertaking installation, testing or maintenance.
Eight steps for studying an engineering drawing.
AGL Visual Encyclopedia: Requirement mapping Cable identification Applicable standard identification
AGL Diagram Library: Available Drawing Categories
The AGL engineering library can be organized into the following categories:
| Category | Example drawing content |
|---|---|
| AGL system diagrams | Overall system architecture and equipment relationships |
| Single-line diagrams | Power distribution, CCRs and lighting circuits |
| Series-circuit diagrams | CCR, primary cable, transformers and light fittings |
| CCR drawings | Model-specific power, control and monitoring connections |
| Transformer diagrams | Primary/secondary connections and product identification |
| Cable and connector diagrams | Primary cable, joints, connectors and secondary leads |
| Runway lighting layouts | Edge, threshold, runway-end, centreline and touchdown zone lighting |
| Taxiway lighting layouts | Edge, centreline, stop bar and guard-light arrangements |
| Approach lighting layouts | Approach bars, rows and associated circuit references |
| ALCMS diagrams | Control architecture, communications and monitoring interfaces |
| CAD installation details | Equipment mounting, cable routing and installation arrangements |
| As-built documentation | Approved records of the installed configuration |
Who Uses AGL Diagrams and Schematics?
AGL design and project engineers
Electrical and airport infrastructure engineers
Installation and commissioning teams
Airport electrical maintenance personnel
AGL testing and troubleshooting teams
Technical and commercial teams preparing BOQs and specifications
Engineering students and trainees learning airport lighting systems
Consultants and project teams reviewing technical submissions
The required level of drawing detail depends on the user’s role and the task being performed.
Explore the AGL Engineering Knowledge Hub
Fundamentals
Standards & Compliance
Runway, Taxiway & Approach Lighting
Surface Movement & Safety
PAPI
Electrical Engineering & Power
Photometry & Testing
Maintenance, Inspection & Safety
Resources, Documentation & Careers
Frequently Asked Questions
Q1What is an AGL schematic diagram?
An AGL schematic diagram is a simplified representation of the electrical or control connections between airfield lighting components. It helps explain how equipment is interconnected and how a system functions.
Q2What is the difference between an AGL single-line diagram and a wiring diagram?
A single-line diagram presents the overall electrical distribution arrangement in simplified form. A wiring diagram shows more specific electrical connections between terminals, components or equipment interfaces.
Q3How does an AGL series circuit work?
A CCR supplies regulated current to a series circuit. Primary cables connect the circuit components, and isolating transformers provide electrical separation for individual light-fitting loads. The exact configuration depends on the approved design.
Q4What does a CCR wiring diagram show?
It may show power input, regulation circuitry, current sensing, protective components, control terminals, status signals and monitoring interfaces. The exact content depends on the CCR model and manufacturer.
Q5What information should an isolating transformer diagram contain?
It should identify the transformer rating, primary and secondary sides, connector arrangement and relevant electrical or installation requirements. Detailed ratings and connections must be confirmed from the manufacturer's documentation.
Q6What is an ALCMS diagram?
An ALCMS diagram represents the architecture and interfaces of the Airfield Lighting Control and Monitoring System, including operator controls, CCR interfaces, monitoring signals and communication arrangements.
Q7Can a typical AGL wiring diagram be used for airport installation?
Not by itself. Installation must follow approved project drawings, current manufacturer documentation, applicable requirements and airport-specific instructions.
Q8Where can I find AGL CAD drawings?
An AGL engineering library can organize drawings by system, equipment type, application and drawing format. Availability depends on the published library content and applicable distribution permissions.
Q9Are AGL diagrams useful for troubleshooting?
Yes. They help identify circuit relationships, equipment references and signal paths. Troubleshooting must also use approved test procedures, equipment manuals and the relevant safety and isolation arrangements.
Q10Why are drawing revisions important?
Revisions identify changes to the drawing. Using an outdated or unapproved drawing can lead to incorrect equipment connections, installation errors or maintenance decisions based on an obsolete configuration.
Q11What is an airfield lighting diagram, an airfield ground lighting diagram or an airport lighting diagram?
An airfield lighting diagram (also called an airfield ground lighting diagram or airport lighting diagram) shows how the lighting system is arranged and connected: power source, CCRs, series circuits, transformers, lights and control. It is a simplified educational view, and the approved project drawings remain the reference for any real airport.
Q12What is an AGL electrical schematic and an AGL schematic diagram?
An AGL electrical schematic, also called an AGL schematic diagram, shows the electrical relationships between equipment using standard symbols rather than physical positions. It helps trace current paths and understand control logic, but it does not show where equipment is located on the airfield.
Q13How to read an AGL schematic?
To read an AGL schematic, start with the legend and symbols, then find the power source and CCR. Follow the series circuit from the CCR output through the primary cable and isolating transformers back to the return. Then trace control and monitoring links, and check the drawing number and revision before relying on it.
Q14What do a runway lighting diagram and a taxiway lighting diagram show?
A runway lighting diagram shows the arrangement of runway lights such as edge, threshold, end and centreline lights and the circuits feeding them. A taxiway lighting diagram does the same for taxiway edge and centreline lights, stop bars and signs. Both are usually layout views, supported by circuit diagrams.
Q15What do a runway edge lights diagram, runway centreline lights diagram, threshold lights diagram and taxiway edge lights diagram show?
These diagrams show where each type of light is placed, how the lights are grouped into circuits and how they connect to the power and control equipment. A runway edge lights diagram, runway centreline lights diagram, threshold lights diagram and taxiway edge lights diagram are normally read together with the layout drawing and the circuit schedule.
Q16What is an airfield lighting wiring diagram, airfield ground lighting wiring diagram or airport lighting wiring diagram?
An airfield lighting wiring diagram, also called an airfield ground lighting wiring diagram or airport lighting wiring diagram, shows how equipment is physically wired: terminals, cable routes, connectors and cores. It supports installation, testing and fault finding, and must match the approved drawings and the as-built records.
Q17What do a runway lighting wiring diagram, taxiway lighting wiring diagram and approach lighting wiring diagram show?
A runway lighting wiring diagram, taxiway lighting wiring diagram and approach lighting wiring diagram show how the lights of each system are connected into their circuits: the cables, transformers, connectors and the CCR or control interface. Each system has its own circuit arrangement so that one failure does not affect the whole airfield.
Q18What do a runway edge lights wiring diagram, runway centreline lights wiring diagram and threshold lights wiring diagram show?
They show how edge, centreline and threshold lights are connected: which circuit each light belongs to, how its isolating transformer is wired and how the circuits return to the CCR. These runway edge lights wiring diagram, runway centreline lights wiring diagram and threshold lights wiring diagram details help installers and maintainers identify the correct circuit.
Q19What is an AGL series circuit wiring diagram and a constant current regulator wiring diagram?
An AGL series circuit wiring diagram shows the loop from the CCR output through each isolating transformer primary and back, with the secondary side feeding each light. A constant current regulator wiring diagram shows the CCR's supply input, output terminals, control interface and earthing. Together they explain how constant current reaches every light.
Q20What are an airfield lighting isolation transformer diagram and an airfield lighting isolation transformer wiring diagram?
An airfield lighting isolation transformer diagram shows the transformer's place in the series circuit, with its primary connected in series and its secondary feeding the light. The wiring diagram shows the primary and secondary leads and connectors. It is used to understand why the circuit continues to operate even when a lamp fails.
Q21What are an airfield lighting cable diagram and an airfield lighting cable wiring diagram?
An airfield lighting cable diagram shows the routes and types of the primary and secondary cables, joints and connectors. The airfield lighting cable wiring diagram shows how conductors are terminated at each end. Both are used for installation, testing and tracing faults.
Q22What are an airfield lighting control system diagram, an airfield lighting control system wiring diagram and airfield lighting control wiring?
An airfield lighting control system diagram shows the operator workstation, controllers, network and CCR interfaces at architecture level. The airfield lighting control system wiring diagram, together with airfield lighting control wiring drawings, shows the signal and power connections between field equipment and control panels. They are used for commissioning and fault finding.
Q23What are an ALCMS diagram and an ALCMS wiring diagram?
An ALCMS diagram shows the layers of the control and monitoring system: operator interface, controllers, communication network and field devices. An ALCMS wiring diagram shows the physical cabling and terminal connections for those parts. Use both with the manufacturer's documentation and the approved project drawings.
Q24What are airfield lighting CAD drawings?
Airfield lighting CAD drawings are the computer-drawn layouts, circuit routes, installation details and schedules used for design and construction. They show positions and dimensions, so they differ from schematic diagrams. Keep the issued revision and approval status under document control.
Explore More AGL Engineering Resources
Continue learning with these related resources. Explore them to build a better understanding of AGL system layouts, electrical schematics, equipment connections and airport lighting engineering.
Engineering & Expert Notes
Know Which Diagram Answers Which Question
ReadingA single-line diagram shows structure, a wiring diagram shows connections and a layout drawing shows location. Using the wrong one leads to wrong conclusions.
Consistent Labels Prevent Site Mistakes
NamingCircuit, CCR and fixture identifiers should match across drawings, panels and field markings. Resolve discrepancies before work begins.
Redline Changes the Day They Are Made
As-BuiltSite changes remembered later are often recorded wrongly. Mark deviations on the drawing at the time and transfer them to the as-built set promptly.
Check the Revision Before Working From a Diagram
Document ControlWorking from a superseded drawing is a common cause of incorrect connections. Confirm the issue status before isolating or reconnecting anything.
Schematic Is Not to Scale
LimitsSchematic drawings convey logic, not physical distances or routes. Use survey and layout records when you need locations or lengths.
Teach New Staff to Trace a Circuit on Paper First
TrainingTracing the circuit on the drawing before going to site builds the mental model that makes fault finding faster and safer.
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