Energised electrical testing is a great addition to thermography in a preventative maintenance program. While thermography generally points out potential problems that may exist within an installation, it is the energised testing that verifies these assumptions. Once a potential problem is identified, the most common practices to pinpoint the exact cause of the fault is to test the equipment for electrical anomalies. Common variables to consider are:
- Current rating of the equipment
- Current draw at time of inspection
- Conductor size is correct for these current ratings (cabling is not overloaded)
- Millivolt drop across equipment contacts
- Voltage and current harmonic distortions present
Once these variables are recorded, we can analyse why excess heat may be present. If the current being drawn through a specific piece of equipment is high, the heat present will also be high (H = I2Rt). It is important to ensure the current rating of the cabling and equipment is not being exceeded. Once this is verified to be within the limits of the Australian standards, you can proceed to testing the voltage drop across the equipment contacts. This verifies any high resistance connections due to loose connections or faulty contacts. This is represented by a voltage difference from line to load side of equipment. Finally, if these last variables are proven to be within acceptable limits there is the potential for heating from excess current and voltage harmonics. Harmonics are distortions in the frequency cycles of the AC waveform in an electrical system.
By verifying the appropriate variables present in the electrical system an accurate analysis of why there is excess heat present in the system can be made and recommendations for repair can be presented to the client. If you want some piece of mind knowing your electrical assets are safe and reliable, give us a call to see how we can assist you.