Cable faults · Low voltage
Cable fault location on low-voltage cables in Bavaria and Baden-Württemberg
When a feeder stays dead, the measurement decides whether one square metre of paving is lifted or fifty metres of footpath. CFT narrows the fault down on buried low-voltage cables, marks the spot at the surface and hands over a report that justifies the road opening – the repair itself remains with your civil or electrical crew. Report the affected feeder on +49 (0) 173 6842932 or at office@cft-de.de, and we will agree isolation, access and an appointment.
What we do on site
Measurement takes place on the isolated cable, disconnected at both ends; the switching operations are carried out by your network operator or qualified electrician. Insulation and resistance measurements first show which cores are affected. Prelocation and pinpointing then narrow the fault down until the excavation can be opened deliberately – every step goes into the report.
Key facts at a glance
| Methods | Insulation and resistance measurement, Time domain reflectometry (TDR), Bridge measurement (Murray loop), Ley effect, Surge and burn-down to make the fault earth-sensitive, Sheath fault location on plastic-sheathed cables, Cable identification in the trench |
|---|---|
| Application range | Buried low-voltage cables in local networks, on industrial premises and estates: distribution cables, service connections from the network side, feeders to halls and sub-distributions |
| Duration | Two hours to one day, depending on the number of faults |
| Result format | Damage report as a PDF |
| Service area | Bavaria and Baden-Württemberg from our Erding base – CFT Group Deutschland GmbH, Lange Zeile 27, D-85435 Erding |
For you as a business
On low voltage, faults are rarely where you expect them: the damage sits at the old joint rather than the freshly excavated section, or in the bend under the driveway instead of the straight run. Whoever digs by instinct pays twice – once for the hole in the wrong place and once for the measurement that follows anyway. With location first, the outage becomes a plannable job: one marked spot, one excavation, one joint.
For municipal utilities and network operators the report matters just as much: it documents methods, readings and the located position in a way that a regulator, an insurer or your own management can follow the decision.
How the job runs
- You report the outage and arrange the isolation – measurement takes place on the de-energised cable, disconnected at both ends.
- Insulation and resistance measurements determine the affected cores and the type of fault.
- Prelocation by time domain reflectometry or bridge measurement gives the distance to the fault; together with the route this defines the search section.
- Pinpointing narrows the position down at the surface and marks it; high-resistance faults are burned down under surge voltage first until they are earth-sensitive.
- You receive the damage report as a PDF – with readings, methods and the marked excavation spot.
Equipment and methods
Low-resistance faults show up in the time domain measurement directly; if the insulation value stays too high, the fault is stressed with surge voltage and burned down until it is earth-sensitive – only then does it yield to measurement. Pinpointing works via the voltage gradient at the surface; where the reflectogram stays ambiguous, the Ley effect narrows down along the route. On plastic-sheathed cables, sheath fault location finds damage to the outer jacket before it grows into a core fault. Where several cables share the trench, cable identification makes sure work happens on the right line.
What you receive
The marked fault position at the surface and an auditable damage report as a PDF: affected cores, methods, readings, distance figures and the location of the excavation spot. That justifies the opening and prepares the repair.
Costs and effort
We charge by deployment time from Erding. The measurement is most economical when isolation and access are settled on arrival – then the time belongs to the location, not the organisation. For network operators with recurring demand we offer per-incident terms.
Frequently asked questions
Does the cable really have to be isolated for the measurement?
Yes. Measurement takes place on the de-energised cable, disconnected at both ends – that is a precondition for the methods and for everyone’s safety. The switching operations are carried out by your network operator or qualified electrician; we agree the sequence beforehand.
The fault comes and goes – can something like that be located at all?
Intermittent faults are usually high-resistance or moisture-dependent. Such faults are stressed with surge voltage and burned down until they answer reliably earth-sensitive – then they can be measured.
How accurate is the location in the end?
Pinpointing leads to the excavation, not to its vicinity: the aim is a marked spot where the joint lies within the opened window. Prelocation alone remains a distance figure – which is why pinpointing at the surface is always part of the job.
Does CFT also carry out the repair?
No. We locate, mark and document; jointing and reinstatement are done by your electrical or civil crew. That keeps the measurement independent of the execution.
Describe the findings.
The more precisely you describe the findings, the more directly we can go to work. Plans, readings and photos help us settle the method in advance.
What happens next
- We read your message and match the case to a method.
- We come back to you – usually with a question that shortens the appointment.
- We confirm the appointment and what it costs before anyone sets off.
Rather talk?
+49 (0) 173 6842932
Describe your case.
Fastest by telephone – then we settle straight away which method fits and what you should prepare.
Or write to office@cft-de.de.