Maintenance Guides 1 min read

Diagnosis of electrical panel overheating: thermography, detection of open connections, harmonic deviations and load balancing

Technical analysis: Troubleshooting electrical panel overheating: thermographic inspection, loose connection detection,

Діагностика перегрівання електричної панелі: термографія, виявлення відкритих з'єднань, гармонічні відхилення та баланс навантаження - UNITEC-D Industrial MRO
Цей гайд допомагає технікам виявити та виправити причини перегрівання електричних панелей, використовуючи термографію, виявлення відкритих з'єднань, вимірювання гармонічних відхилень та балансування н

1. Problem Description and Scope

This guide is dedicated to identifying and correcting the causes of overheating of electrical panels in industrial installations. Symptoms include high surface temperature, unstable power supply, increased noise, as well as possible tripping of automatic circuit breakers. Overheating of electrical panels is a critical issue since it may lead to emergency shutdown, fire, or damage to equipment.

2. Safety Precautions

Turn off the power supply before starting the diagnostics. Use appropriate PPE (personal protective equipment), including work gloves, goggles and safety instructions. Carry out the locking and tagging process of electrical lines in accordance with the standards DSTU 3020-95 and ISO 50001.

3. Required diagnostic tools

Tool Name Model/Specification Measurement range Objective
Thermographic camera FLIR T650sc –20°C to 1600°C High temperature zone detection
Multimeter Fluke 434 II 0-600V, 0-2000Ω, 0-200A Voltage, current, resistance measurements
Vibration Analyzer SKF Vibrometer 3180 0-10,000 Hz Vibration Deviations Detection
Temperature Measurement Lighting Thermalert T410 –20°C to 200°C Temperature evaluation of individual elements

4. First inspection: checklist before starting the diagnostics

Item Action
1 Record the ambient temperature.
2 Check the alarm history and errors.
3 Record the current values of voltage and current.
4 Verify whether the panel parameters have not changed.
5 Check for moisture or contamination.

5. Systematic Diagnostic Scheme

  1. Symptom: Overheating of the electrical panel
    1. Use thermography to identify areas with high temperature.
    2. Check whether the temperature is higher than 60°C on open connections.
    3. If the temperature is higher than 80°C, perform additional checks.
  2. Symptom: Unstable operation of the panel
    1. Measure the voltage and current on all connector branches.
    2. Determine whether the values deviate from the nominal values.
    3. Use a vibration analyzer to detect vibration deviations.
  3. Symptom: Tripping of circuit breakers
    1. Check for harmonic distortions in the electrical network.
    2. Measure THD (Total Harmonic Distortion) at the input and output terminal blocks.
    3. If THD exceeds 5%, perform additional diagnostic actions.
  4. Symptom: Unstable load
    1. Use a balancing analysis to evaluate the load distribution.
    2. Check whether the load is evenly distributed among the phases.
    3. If the difference between phases is more than 10%, perform balancing.

6. Failure Cause Matrix

Symptom Likely causes (on the probability scale) Diagnostic Testing Expected result
Panel Overheating
  1. Open connections (70%)
  2. Incorrect load distribution (20%)
  3. Harmonic deviations (10%)
  1. Measure the temperature on open connections.
  2. Check the load distribution between phases.
  3. Measure THD at the terminal connections.
  1. Temperature > 80°C – open connections.
  2. Phase difference > 10% – uneven loading.
  3. THD > 5% – harmonic distortions.

7. Detailed Cause Analysis

7.1. Open connections

Open connections occur due to terminal damage, incorrect connection or mechanical deviations. This leads to increased resistance, causing heating. If this is not corrected, it may result in tripping of circuit breakers or fire. Check the temperature of connections with an infrared device.

7.2. Uneven loading

Uneven loading occurs due to incorrect connection or phase imbalance. This leads to uneven current distribution, which may cause panel overheating. Check the phase difference using a multimeter.

7.3. Harmonic Deviations

Harmonic distortions occur due to improper electrical equipment or low quality power supply. This leads to an increase in power losses, which may cause panel overheating. Measure THD using a measuring instrument.

8. Step-by-step correction procedures

8.1. Correction of Open Connections

  1. Disconnect the power supply.
  2. Check the terminals for damage.
  3. According to the technical passports, solder or clamp the connections.
  4. Measure the resistance of the connections – it should be less than 0.1 Ohm.
  5. Turn on the power supply and check the temperature.

8.2. Correction of Uneven Loading

  1. Measure the current on all phases.
  2. Check whether the difference between phases is more than 10%.
  3. Load redistribution between phases.
  4. Measure the current after balancing – the difference should be less than 5%.
  5. Turn on the power supply and check the temperature.

8.3. Harmonic Deviation Correction

  1. Measure THD at the terminal connections.
  2. If THD exceeds 5%, perform filtering.
  3. Install the harmonic distortion filters according to the technical passports.
  4. Check THD after installing filters – should be less than 3%.
  5. Turn on the power supply and check the temperature.

9. Preventive Measures

Cause Preventive strategy Monitoring method Recommended interval
Open connections Periodic inspection of terminals Thermography Monthly
Uneven loading Load balancing Multimeter Monthly
Harmonic deviations Harmonic distortion filtering Measuring instrument Annual

10. Replaceable Parts and Components

Component description Specification When to replace Category UNITEC-D
Terminal for connection 16A, 250V After detection of an open connection Category 501
Harmonic distortion filter 100A, 400V After detection of THD > 5% Category 503
Temperature Measurement Lighting –20°C to 200°C After tripping the automatic circuit breaker Category 502

Go to our e-catalog: https://www.unitecd.com/e-catalog/

11. Additional Materials

See also:

Applicable standards: DSTU 3020-95, ISO 50001, EN 50160.

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