Cable fault location is about finding where an underground (or otherwise inaccessible) cable has failed so repairs can be targeted and safe.
What a “cable fault” can look like
Faults can present in different ways:
- A protective trip that won’t reset
- Intermittent trips that clear and return
- Insulation deterioration that shows up in testing before failure
- Sheath-related issues (depending on cable type and installation)
The symptoms influence what testing approach is appropriate.
Why route information matters so much
Even excellent fault location work can be slowed down by missing information. What helps most:
- Cable type and approximate length
- Termination points and how the circuit is configured
- Route drawings, duct runs, joint bays, and any known repairs
- Any previous test results or event logs
If the route is uncertain, the scope may include additional confirmation steps.
The safety reality
HV/MV cable work is high-consequence. A credible approach always includes:
- Controlled isolation and verification steps under site rules
- Clear responsibility for permits and authorisations
- A plan for excavation and repair that doesn’t assume the “first guess” is correct
If someone skips over safety or permits in the discussion, treat that as a serious red flag.
Common questions
Can you always find the exact fault point?
It depends on the failure mode, route complexity, access, and data quality. Good providers will talk about confidence and uncertainty, not false precision.
Do we need to dig up the entire route?
Usually not. The goal is to narrow down the location so excavation is targeted — but access constraints and route uncertainty can broaden the work.
Is fault location the same as repair?
Often different parties handle location and repair. Clarify who owns what scope and what post-repair testing is required.
Related guides
- Service overview: Cable Fault Location.
- If substations are in scope: Substation Services and Substation Maintenance Basics.
- Request a quote: Contact.
Disclaimer: This guide is informational only. HV/MV cable fault investigation and repair is safety-critical and must be performed by qualified, authorised professionals under site rules and applicable standards.