PHOTOMETRIC COMPLIANCE VS ELECTRICAL COMPLIANCE
Does It Light Correctly vs Does It Operate Correctly — photometric compliance verifies whether an AGL light produces the required optical performance, while electrical compliance verifies whether the AGL equipment meets the required electrical performance and safety requirements. Passing one does not automatically mean passing the other.
At a Glance
| Feature | Photometric Compliance | Electrical Compliance |
|---|---|---|
| Main focus | Optical performance | Electrical performance and safety |
| Main question | Does the light produce the required light output? | Does the equipment operate electrically as required? |
| Typical parameters | Intensity, beam distribution, colour | Current, voltage, power, insulation |
| Typical units | cd, lx, cd/m², chromaticity values | V, A, W, Ω |
| Beam measurement | Yes | No |
| Colour verification | Yes, where required | No |
| Electrical safety | No | Yes |
| Electrical operation | Indirectly only | Primary focus |
Easy memory: Photometric compliance = LIGHT OUTPUT. Electrical compliance = ELECTRICAL OPERATION.
Verifying the Light Produced
Photometric compliance concerns the light produced by the fixture. The main question is whether the fixture emits the required light in the required directions.
Typical checks
- Luminous intensity
- Peak intensity
- Intensity distribution
- Horizontal photometry
- Vertical photometry
- Beam spread
- Required angular coverage
- Light colour and chromaticity, where applicable
Verifying the Equipment's Electrical Behaviour
Electrical compliance concerns the electrical characteristics and safety of the equipment. The exact tests depend on the equipment type and the applicable specification.
Typical checks
- Rated voltage
- Operating current
- Power consumption
- Electrical continuity
- Insulation resistance
- Dielectric strength
- Earthing/bonding, where applicable
- Connector and cable suitability
- Electrical protection requirements
How Does It Light vs How Does It Operate
Photometric
How does it light?
Measured in cd, beam distribution, and colour.
Electrical
How does it operate?
Measured in V, A, W, and Ω.
Easy memory: Photometric compliance = LIGHT OUTPUT. Electrical compliance = ELECTRICAL OPERATION.
A Fixture Can Pass Electrical Compliance but Fail Photometric Compliance
This is an important distinction. An AGL fixture may draw the correct current, consume the expected power, and have acceptable insulation — yet still produce insufficient luminous intensity.
Possible causes
- Optical degradation
- Dirty or damaged lens
- LED degradation
- Lamp ageing
- Optical misalignment
Correct electrical operation does not automatically guarantee correct photometric performance.
A Fixture Can Pass Photometric Testing but Have an Electrical Problem
The reverse can also occur. The fixture may currently produce sufficient light but still have an electrical defect affecting safety or reliability.
Possible causes
- Damaged insulation
- Water ingress affecting electrical parts
- Loose connection
- Incorrect grounding
- Abnormal power consumption
Correct light output does not automatically prove electrical safety or reliability.
What Each Compliance Category Measures
Photometric Compliance
- Intensity → cd
- Illuminance → lx
- Luminance → cd/m²
- Beam distribution
- Beam spread
- Colour characteristics
Electrical Compliance
- Voltage → V
- Current → A
- Power → W
- Resistance → Ω
- Insulation resistance
- Dielectric performance
LED Runway Edge Light
Consider an LED runway edge light, and how each compliance category questions it differently.
Photometric asks
- Is the intensity sufficient?
- Is the beam correctly distributed?
- Does it provide the required angular coverage?
- Does the emitted colour meet requirements?
Electrical asks
- Does it operate at the required electrical rating?
- Is the current within specification?
- Is power consumption acceptable?
- Is electrical insulation adequate?
- Are electrical connections safe?
These are two different compliance categories, and a single fixture can pass one while failing the other.
Instruments Used for Each Test
Photometric Testing
- Goniophotometer
- Photometer
- Lux meter
- Colour-measurement instrument
Electrical Testing
- Multimeter
- Insulation resistance tester
- Power analyser
- Current measurement equipment
- Dielectric test equipment
The exact instruments and procedures depend on the required compliance test.
Compliance at the Fixture and the System Level
These dimensions can also apply at different levels. A complete evaluation may require both the fixture and the associated electrical system to be assessed.
Electrical compliance can involve the operation and integrity of this supply system, while photometric compliance focuses on the resulting optical performance of the light.
How Faults Show Up in Each Test
| Condition | Photometric Compliance | Electrical Compliance |
|---|---|---|
| Low light intensity, normal current | Fail | May pass |
| Correct light output, damaged insulation | May pass | Fail |
| Incorrect beam alignment | May fail | May pass |
| Incorrect operating current | May affect light output | Fail |
| Wrong colour, correct electrical operation | Fail | May pass |
| Electrical supply interruption | Light unavailable | System failure |
How Electrical Input Relates to Light Output
Electrical performance influences photometric performance, but they remain separate requirements. A problem in the electrical input can affect the light output.
However, correct electrical input passing through damaged optics still results in incorrect light output:
So electrical compliance alone cannot confirm the complete optical performance.
Full Engineering Parameters
| Parameter | Photometric Compliance | Electrical Compliance |
|---|---|---|
| Primary focus | Light | Electricity |
| Main output | Optical performance | Electrical performance |
| Intensity | Yes | No |
| Beam distribution | Yes | No |
| Colour | Yes, where applicable | No |
| Voltage/current | No | Yes |
| Insulation | No | Yes |
| Electrical safety | No | Yes |
| Optical performance | Primary purpose | Indirect relationship |
| Typical result | Meets/does not meet optical requirements | Meets/does not meet electrical requirements |
Photometric Compliance vs Electrical Compliance
Passing one does not automatically mean passing the other. A fixture can be electrically compliant but photometrically deficient, or photometrically acceptable while having an electrical safety or reliability defect.
Photometric compliance verifies that the AGL light produces the required intensity, distribution, and other specified optical characteristics. Electrical compliance verifies that the AGL equipment operates within its required electrical parameters and safety requirements. For complete AGL compliance, both must be evaluated independently.
For AGL: think of photometric compliance when discussing whether the light performs correctly visually, and electrical compliance when discussing whether the equipment operates correctly and safely.
Engineering & Expert Notes
Verify Both for Acceptance
PrincipleOne does not imply the other.
Complete Electrical Checks Before Photometry
SequenceElectrical safety and correct operation come first.
Report Both Separately
ReportingKeep results clear.
Retest Both After Repairs
VerificationChanges can affect either.
Frequently Asked Questions
Photometric → LIGHT (does the fixture produce the required optical output). Electrical → OPERATION (does the equipment run correctly and safely).
Yes. A fixture may draw the correct current and power while still producing insufficient intensity due to optical degradation, a dirty or damaged lens, LED or lamp ageing, or optical misalignment.
Yes. A fixture may currently produce sufficient light while having a defect such as damaged insulation, water ingress, a loose connection, or incorrect grounding that affects safety or reliability.
Yes, indirectly — the electrical input drives the fixture that produces the light output, so a problem in the electrical input can affect what is emitted. However, correct electrical input alone does not guarantee correct optical output if the optics are damaged.
Photometric testing typically uses a goniophotometer, photometer, lux meter, or colour-measurement instrument. Electrical testing typically uses a multimeter, insulation resistance tester, power analyser, current measurement equipment, or dielectric test equipment.
Yes. A complete evaluation may require both the fixture and the associated electrical system to be assessed — photometric compliance for the resulting light, electrical compliance for the supply system and fixture's electrical behaviour.
Governing Documents
For an actual project design, always verify the current edition of the applicable documents.
FAA AC 150/5340-30
Design and Installation Details for Airport Visual Aids — photometric requirements relevant to interpreting fixture optical performance in AGL specifications.
ICAO Annex 14, Volume I
Aerodrome Design and Operations — photometric characteristics of aeronautical ground lights, intensity and colour requirements.
FAA AC 150/5345-53
Airport Lighting Equipment Certification Program (ALECP) — the FAA framework under which third-party certifiers test AGL equipment against its individual specification's photometric and electrical requirements before listing.
Final Engineering Note
Do not treat electrical test results as proof of photometric performance, or photometric results as proof of electrical safety. Confirm which compliance category the governing standard actually requires before selecting a test method or acceptance criterion.
Electrical compliance is not photometric compliance — one describes how the equipment operates, the other describes what it produces.
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