Maximising profit is important to any business but so too is the avoidance of loss. A production process may be optimally designed but, if it is frequently interrupted by the failure of electrical systems that power and control it, the result can be catastrophic.
Total operation costs increase, personnel safety is compromised and fire risk escalates. Indeed, it is estimated that around 35% of all industrial fires are caused by electrical faults.
This is why manufacturers are increasingly using thermal imaging in their predictive maintenance and condition monitoring programme. The technology has proved itself to be cost effective and highly versatile and IRISS – manufacturer of industrial grade infrared windows - reports that regular thermal imaging surveys are now commonly stipulated by insurance companies as a condition of coverage to minimise their own exposure to risk.
The traditional approach is open-panel inspection during routine shutdown but it is both time-consuming and a poor use of high-value electrician and thermographer resources. Typically, the total time it takes for a three man electrical RCM team to inspect just one electrical panel is around five hours when PPE suit-up and waiting time is factored in.
Nevertheless, this pro-active strategy is still paying dividends but there is no doubt that the most valuable quantitative data is only gathered when the electrical system is energised and under load. But, live testing is a risky and costly business. Some systems are even considered to be too hazardous to maintain in this way and often this results in critical systems being inspected less frequently and sometimes, not at all.
So, on the one hand, the advice from safety organisations is to keep all live electrical systems closed. Yet, teams need to open up systems for repair and also to take measurements while they are energised so that the nature of the fault and its severity can be determined. It’s a catch-22 but a new approach is providing the answers.
Closed and guarded
Thermal imaging windows have been leading the way as a safe method of inspecting both energised electrical systems and operating mechanical systems. And now there is an increasing trend towards the incorporation of other electrical maintenance safety devices (EMSDs) into basic systems designs too.
It is a move that is supported by safety organisations, such as the IEEE with its ‘Safer by Design Initiative’. This encourages the inclusion of EMSDs into enclosures and panels at the point of manufacture. The clear benefit is that they allow meaningful maintenance tasks to be completed whilst the system remains closed and in a safe and guarded condition.
In this way, the inspector is never exposed to the dangers of arc flash or electrocution and the process can be completed in a fraction of the time by comparison with open panel inspection. Personnel safety is assured and the health of the electrical system can be frequently and cost effectively monitored. This includes many systems that were previously considered to be too dangerous for live inspection.
While it is best to include EMSDs at OEM level, it doesn’t preclude installed systems from being made safer and more reliable too. A wide range of EMSDs, including thermal imaging windows, are now available that can be retrofitted too. For example, a dedicated port allows an ultrasound probe to listen for corona when the air gap is starting to break up around the electrical connection; the first sign of failure.
Motor current analysis tap off ports and voltage detection ports can also be considered. The scope of this concept also includes continuous monitoring and online systems such as vibration and air partial discharge analysis. Another option is delta T measurement that acts as an early warning system if the temperature in the electrical enclosure exceeds a pre-set threshold.
The inclusion and EMSDs, either when the system is specified or when it’s in the field, is proving an excellent way of minimising multiple risks. They avert electrical fires, minimise loss of production and safeguard maintenance engineers. They are a win-win for any business.
Tags: IRISS, Panel Building News, e-lec.org, Infrared Windows