When Your Internal Team May Not Be Enough
Most industrial facilities have in-house electricians who handle routine work. The problems that tend to require a specialist field service technician often share certain characteristics.
Intermittent Faults
The production line stops randomly, the fault clears itself, and nobody can reproduce it. These can be among the most costly problems in industry because repeated short stoppages add up. Diagnosing them often requires systematic methodology, data logging equipment, and experience from similar cases.
Power Quality Issues
Voltage sags, harmonic distortion, transients, and imbalance may not be visible on standard multimeters. They can manifest as unexplained drive faults, premature motor failures, or erratic PLC behaviour. Diagnosing them typically requires power quality analysers and the expertise to interpret the data.
Medium Voltage Systems
Work above 1,000V AC generally requires authorised personnel with specific qualifications and PPE. Most in-house teams may only be qualified for low voltage work.
Complex Drive and Motor Systems
Modern servo systems, high-power VFDs, and regenerative drive configurations can have failure modes that go beyond checking for open circuits. Diagnosing issues in these systems may require both electrical knowledge and familiarity with the specific drive platform.
What Diagnostic Technicians Typically Do on Site
A structured diagnostic engagement generally follows a sequence: reviewing fault history and available data, conducting visual inspection, performing systematic measurements, deploying data logging equipment where needed for intermittent faults, analysing collected data, and presenting findings with recommended corrective actions.
The deliverable is ideally a diagnostic report that documents the root cause, the evidence, and the recommended fix—useful for preventing repeat failures and supporting insurance or warranty claims.
Common Diagnostic Disciplines
| Discipline | What It Generally Covers | Equipment Often Used |
|---|---|---|
| Thermographic Survey | Detecting hot spots in switchgear, connections, motors, and transformers | FLIR thermal cameras or similar |
| Power Quality Analysis | Measuring harmonics, voltage sags/swells, transients, flicker, power factor | Dedicated power quality analysers (e.g. Fluke, Hioki, Dranetz) |
| Motor Testing | Winding insulation resistance, surge testing, vibration analysis, bearing condition | Insulation testers, vibration analysers |
| Cable Fault Location | Pinpointing faults in buried or concealed cables | TDR-based cable fault locators |
| Protection Relay Testing | Verifying overcurrent, earth fault, and differential protection settings | Relay test equipment (e.g. Omicron, Megger) |
| Drive Diagnostics | VFD fault analysis, parameter optimisation, encoder/resolver faults | Manufacturer-specific software, oscilloscopes |
Qualifications to Consider
For electrical diagnostic work in European industrial facilities, qualifications are generally governed by national regulations. It is typically worth looking for national electrical authorisation appropriate to the voltage level of your installation, thermography certification for thermal survey work, and manufacturer-specific training if VFD diagnostics are involved. Requirements vary by country and jurisdiction, so checking what your local regulations and insurance require is advisable.
For hazardous areas (ATEX zones), specialised certification such as CompEx or equivalent is generally considered mandatory in most European jurisdictions.
Cost Considerations
Diagnostic work is often charged as a day rate plus equipment rental where specialist instruments are needed. For intermittent faults, expect the engagement to potentially include an initial assessment visit, a period of data logging (equipment left on site), and a return visit for analysis and reporting.
The cost of a thorough diagnostic engagement is often significantly less than the cumulative production losses from an unresolved intermittent fault.
Disclaimer: This guide is provided for general informational purposes only and does not constitute professional, legal, or financial advice. All rates, timelines, and market data referenced are indicative estimates based on general market observations and may not reflect current conditions. Actual costs, qualifications, and regulatory requirements vary by country, industry, and project. Always verify information with relevant local regulations, obtain professional advice where appropriate, and request multiple quotes before committing to any engagement. FindFST accepts no liability for decisions made based on the content of this guide.
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