What is electrical inspection?
The structured check of the electrical side of a lighting circuit — isolate and prove dead, inspect connections and equipment, measure insulation, continuity and earthing, then judge the readings and record them.
Electrical inspection checks that the circuit is electrically sound, not just that it looks sound. The sequence is prepared and permitted, then the circuit is isolated and proved dead, connections and equipment are inspected, insulation, continuity and earthing are measured, and the readings are judged against limits and past results before the circuit is restored.
Series circuits run at constant current, so an open or disturbed circuit can be hazardous. Nothing is opened or touched until the circuit is isolated, locked out and proved dead under the airport’s permit-to-work. A single reading shows the condition on the day; the trend across inspections is what reveals slow deterioration.
- Prepare. Obtain the permit, collect drawings and previous readings, and confirm instruments are in calibration and working.
- Isolate. Switch off, lock out and prove the circuit dead with a suitable instrument, then earth it as the procedure requires, before any hands-on work.
- Inspect. Examine connectors, terminations, cable entries, transformers and bonding for corrosion, damp, heat marks and damage.
- Measure. Test insulation resistance, continuity and earth resistance following the manufacturers’ and site procedures. Discharge the cable after each insulation test, before it is touched.
- Judge. Compare each reading with limits, commissioning values and earlier results, and decide what needs repair.
- Restore & log. Remove temporary earths, tools and locks as the permit allows, re-energise, verify the lights, then record readings, defects and repairs.
Frequently Asked Questions
Q1What is electrical inspection in airfield ground lighting?
It is the structured check of the electrical side of a lighting circuit: connections, terminations, cables, transformers, constant current regulators and earthing. It combines close inspection with measurements such as insulation resistance, continuity and earth resistance, carried out with the circuit isolated, locked out and proved dead.
Q2How is electrical inspection different from visual inspection?
Visual inspection looks at the installation, mostly from the outside and partly while it is lit. Electrical inspection is hands-on and uses test instruments, so it is done only on an isolated circuit. Visual findings often decide where the electrical inspection should concentrate.
Q3Why must the circuit be proved dead before inspection?
Series lighting circuits are driven at constant current, and an open or disturbed circuit can produce hazardous voltage. Isolating, locking out and proving the circuit dead with a suitable instrument removes that risk before covers, connectors or cable entries are opened.
Q4Why do readings matter more as a trend than as a single value?
A single reading shows the condition on the day, but a falling insulation resistance or rising earth resistance over several inspections shows deterioration before a fault occurs. Comparing against commissioning and previous results is how the inspection finds problems early.
Q5What should be recorded?
The circuit and equipment identifiers, the instrument and test settings, each reading with date and conditions, any defects found, repairs made and the inspector. Consistent records support trending, acceptance decisions and corrective work orders.
Q6What limits and intervals apply?
Acceptance limits and intervals come from the airport's maintenance programme, the regulator, the equipment manufacturers' instructions and the applicable standard. Always use the values for your site rather than a generic figure.
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