The field problem
Telecommunications Tower — New Alamein
Communication antennas extended above the installed air terminal; down-conductor routing also lacked a clear separation-distance assessment.
why the obvious answer can be misleading
The highest exposed equipment could fall outside the intended protection volume. During a lightning event, insufficient separation can allow side-flash/flashover from the LPS to structural or equipment parts.
Why it failed
The highest exposed equipment could fall outside the intended protection volume.
During a lightning event, insufficient separation can allow side-flash/flashover from the LPS to structural or equipment parts.
Follow the engineering
Switch between the field condition and the engineering concept. Trace the path and examine what changes.
Inspect the engineering detail
What changes
Relocate/extend the interception system so antennas are within the calculated protection zone; verify separation distance and route the down conductor as directly as practical with controlled bonding.
Correction & verification
Relocate/extend the interception system so antennas are within the calculated protection zone; verify separation distance and route the down conductor as directly as practical with controlled bonding.
Verification recorded in the case
- Re-check protection geometry and continuity after modification.
- Record as-built topology and connection points.
- Repeat the measurement or functional test under a defined condition.
- Confirm continuity and mechanical integrity of the corrected path.
- Document instrument/setup, environmental condition and test method.
- Close the NCR/case only when evidence supports the conclusion.
References & project context
References are reproduced from the PIS casebook. Select the governing edition and project acceptance criteria before using them for a design. The diagrams explain the concept, rather than define construction dimensions.
IEC 62305-3; NFPA 780 where specified.
PIS reviewed field handbook · PIS-CS-034
View the original social cardThe engineering lesson
The highest point should be the engineered interception system — not the equipment you are trying to protect.
Take the lesson into your next design review.