Underground Troubleshooting Flashcards
What’s the first goal after a cable faults?
Restore service quickly by identifying the general area of the fault.
Who is responsible for mastering troubleshooting tools?
The Qualified Electrical Worker.
When is a grounding spike used?
After locating a fault to ensure the cable is grounded at the work location.
Is a grounding spike sufficient on its own?
No, it’s used in addition to other grounding methods.
What is a grounding spike?
A C-clamp device that punctures the cable conductor to ground it.
What tool is used to install a grounding spike?
A voltage-rated hot-line tool (shotgun stick).
What’s the number one cause of cable faults
Poor workmanship in splicing or terminating.
Why is bending radius important during installation?
Excessive bending can damage the cable and cause faults.
What’s the minimum bending radius for tape-shielded cable?
12× the cable’s outside diameter.
What happens with sidewall pressure during pulling?
It can damage insulation and reduce cable lifespan.
Why is using a pickup truck to pull cable a bad idea?
It can apply thousands of pounds of pressure, damaging the cable.
How does poor backfill cause puncture faults?
Rocks in soil press against the cable, damaging insulation
What is the recommended bedding for direct burial cable?
4 inches of sand below and above the cable.
What is a common source of abrasion damage?
Dragging cable over rocks or sharp surfaces.
What’s a simple way to prevent cable abrasion?
Feed cable off the reel and use rollers.
What causes corrosion in underground cables?
Water ingress through poor riser installations or breaks
How does corrosion lead to insulation failure?
It destroys the drain wire, leading to arcing and insulation breakdown.
What is “treeing”?
Damage from contaminated water forming tree-like paths in insulation.
How can treeing be prevented?
Seal conduit openings and apply proper environmental protection.
What is the first clue of an underground fault?
Customer power outages.
Where should the first physical check be made?
At the takeoff point to see if the tap fuse opened.
What must workers avoid doing with cutouts?
Refusing (manually re-energizing) the cutout without authority.
What tools assist in locating cable faults during patrols?
Maps and visual inspection.
