Arc Flash Myths

Sep 27, 2021 | Arc Flash Study

Within the electrical industry, most workers have become familiar with the term arc flash and the hazard it represents. While training and education have helped in understanding the hazard as well as methods for workers to protect themselves from it, there are still some gaps in industry application that need to be addressed. Below is a collection of some of the most common myths that arise with companies that are developing their electrical safety programs. Before jumping into the various misconceptions, it’s important to establish a clear understanding of what the arc flash hazard is. To find out, check this out.

Arc flash explosions are rare

Electrical work by its nature is dangerous due to the high energy levels involved. Most importantly, electricity is odourless, colourless, and invisible. Most often, accidents may occur when you perform routine maintenance. By having this mindset, you can develop a complacency to your routine job. This complacency leads to unpreparedness to any changes that happen to the system. Ultimately leading to a human error that can cause a problem.

Hazard labeling equals compliance with NFPA-70E

To work on any energized equipment above 50 volts, an energized work permit is required. A work permit is critical and cannot be bypassed by a simple labeling system. Employers and management are directly responsible for work permitting, safety programs, training and planning.

Arc flash analysis is simply panel labeling

Analysis is about hazard reduction and detecting and possible faults that may occur in the system. It is a preventative measure to avoid flashes from happening. Whilst also being predictive, by knowing the strength of the possible arc flash if it were to happen. Such measurements determine the qualified personnel and PPE required.

Regular infrared scans of equipment rule out doing an arc flash analysis

Arc flash can be caused by equipment failure or loose connections. But most injuries are caused by human error and will only be avoided through regular analysis of equipment, work practices, and safety training programs. A thermal scan can only detect faults in the equipment. An arc flash analysis looks at the bigger picture by assessing the rated power and currents used and safety protocols put in place.

No hazards beyond the motor control centre

The motor control centre is the final access point of power for motor loads, but this doesn’t mean there isn’t a need to assess other loads, which are fed from it. Wherever there is a current of electricity, there lies a potential risk of arc flash.

There’s no hazard if there’s no exposed, energized conductors or circuit parts

For most equipment, the probability of an explosion may be very low, but it’s certainly not impossible. Inserting or removing draw-out circuit breakers, bus plugs and motor control centre buckets can cause an arc flash where, normally, there is no perceived hazard — “normally” operating electrical equipment has been known to fail.

Downstream current is less violent

This myth stems from this belief: “If a panel is rated less than 1.2 cal/cm2, then everything else downstream is also less than 1.2 cal/cm2.” This seems like it is a logical assumption, and in a lot of cases it will likely be correct. However, considering the severity of the outcome of an arc flash event, it is not safe to make this assumption.