Thermography

 

AVID’s Thermo-graphic Testing of Electrical Equipment process

Thermography is a non-destructive test (NDT) method that may be used to detect poor electrical connections, unbalanced loads across phases, deteriorated insulation on cables, or other potential problems in energized electrical/mechanical components and switchboards. These problems may lead to excess power consumption/use, increased maintenance costs, or catastrophic equipment failure resulting in unscheduled service interruptions, equipment damage, or other problems.

 

In addition, AVID’s electrical thermography is key to assist not just you the property owner but also the employees of your organisation that looks after your electrical equipment. Electrical safety is paramount to your organisation. AVID electrical maintenance division endeavors to continue to keep track of your equipment and asset through our latest asset software tracking system. AVID employees will periodically investigate your assets utilising thermo-graphing every piece of equipment and notify the engineers and owners if any changes or not with our reporting system.

 

How Does Thermography Work?

Thermography, also called infrared inspection, is based upon the sensing of heat emitted from the surface of an object in the form of infrared radiation. Test instruments are used to detect and convert the infrared radiation into either a temperature value or a thermal image, which can be used to assess the thermal condition of the object at the time of measurement. At AVID, we normally use FLIR infrared camera for imaging purposes.

 

How Can Thermography Be Used to Inspect Electrical Equipment?

Normal energized electrical systems generate heat because of electrical resistance (ohms law). The amount of heat generated is related to the amount of current flowing through the system and the resistance of the individual system components and connections within the system. As components deteriorate slowly over time, their resistance increases, causing a localized increase in heat. Similarly, a poorly made connection will have higher resistance than a well-made connection, along with a higher temperature profile. Thermography should be utilised to detect these temperature differences.

What Are the Benefits of AVID’s Thermographic Inspection?

The National Fire Protection Association (NFPA) estimates that 10% of the fires occurring in manufacturing properties are related to electrical system failures, such as failure of electrical insulation, terminals, and related components. Additionally, failures can cause employees to be exposed to live electrical circuits, making them susceptible to serious injury or death from electrocution. By early detection of high-resistance connections and repairing them, the likelihood of an insulation breakdown of the electrical wires and will be reduced.

Other advantages to detecting and repairing these electrical and mechanical faults are the cost savings from energy conservation, lower power outage and repair costs. High resistance in circuits normally will cause an increase in current flow. When current flow is increased, the results will be higher power consumption without the owner even knowing. Further, high current draw can cause critical electrical circuit components, such as fuses, circuit breakers, and transformers, to fail prematurely. These failures result in higher maintenance and repair costs, and ultimately your business suffers.

 

Who May Perform Thermographic Inspections?

AVID’s thermo-graphic division can assist in performing regular inspections at your location. Because thermo-graphic imaging equipment can be complex, persons performing evaluations require special training. In addition, there is a potential for exposure to “live” electrical components. Our employees have years of expertise in this area.

Our employees during inspections shall at all times wear protective equipment for the eyes or face wherever there is danger of injury to the eyes or face from electric arcs or flashes or from flying objects resulting from electrical explosion. If you are interested in more information, please look at AS 3998- 2006, Non-destructive testing paper.

Furthermore, Article 130 of NFPA 70E, Standard for Electrical Safety in the Workplace, provides details on the level of protection required based on the arc flash potential present.

When is AVID’s Thermographic Scan Needed for your business?

While all properties can benefit from a thermographic scan, those with high power consumption, multiple branch circuits and distribution subsystems, or heavy equipment have the greatest need. Businesses with high electrical demands should have a thermographic scan performed at least annually on critical systems, such as switchboards, switchgears, and transformers. Based on the scan results, a schedule to rescan should be based on the types of equipment, power consumption, and age of the electrical systems. AVID qualified electrician can assist the property owner in determining what and how often to conduct scans.

NFPA 70B, Recommended Practice for Electrical Equipment Maintenance, published by the NFPA, provides a listing of maintenance and equipment testing intervals in Annex L. In addition to these recommended intervals, some conditions and circumstances may specifically warrant a thermographic scan. These include:

Power Systems and Equipment

  • Power systems having electrical services greater than 110 volts.
  • Step-up or step-down power transformers onsite.
  • Power transfer circuits, such as switchgears and relays.
  • Modifications to electrical panels, power control boxes, and sub-distribution boards.
  • Buildings with electrical wiring and joints.
  • Motor starter circuits.
  • High torque and heavy current draw motors.
  • Presence of high output lighting equipment, such as mercury vapor lamps.
  • Use of uninterruptible power supplies (UPS).

 

Observations

  • An increase in power consumption without an increase in equipment use.
  • Reports of motors and other electrical equipment “slowing down.”
  • Dimming of lighting (voltage sag) when other equipment is started.
  • Unexplained power surges noted in computer, processing, or building service equipment.
  • Unexplained odour of burning plastic or rubber in the area of electrical panels, wiring, or equipment.
  • Electrical equipment temperature changes.

 

Property History

  • Previous occurrences of fluorescent lighting failures or frequent bulb changes.
  • Construction or repair activities that result in added electrical demand.
  • Damage to facilities from fire, flood, earthquake, or other similar disasters.
  • Previous occurrences of electrical system fires.