Cable strikes are unfortunately a common occurrence. Of the millions of excavations that take place each year, tens of thousands of cable strikes occur, leading to various injuries, damage to equipment and property, and in the worst cases, fatalities.

Essentially, these dangerous strikes occur when machinery or tools come into contact with a live cable or underground service and create a kind of electrical explosion or electrocution event. As you would imagine, the kind of injuries that occur when these cables are hit are extremely serious.

As such, it’s important that all operatives working in the excavation and utility surveying sector have a good understanding of the dangers they face as well as ways to mitigate the risk of cable strikes and arc flashes from occurring.

What Are Arc Flashes?

An arc flash (also called a flashover) is a type of electrical explosion or discharge that results from a connection from the air to the ground (earthed component) in an electrical system. Temperatures at the source of an arc flash can reach 20,000 °C.

Many mistake arc flashes as simple electric shocks and more awareness is needed about the true dangers of a cable strike. This means not enough people are adequately protecting themselves against them when they occur, through prevention methods as well as protective gear to minimise harm to the body.

Injuries can include external skin burns, internal burns and intoxication from inhaling hot gasses and vaporised metal, hearing damage, eye damage and blindness from the ultraviolet flash, as well as many other serious injuries.

Unfortunately, the kind of activities that cause these arc flashes is varied and some are not aware that what they’re doing can lead to such an event. Anyone involved in excavation for the purpose of construction (building, fencing, piling or other activities) should be trained in the dangers, not just a select few workers.

Rather than focusing efforts on utility surveyors alone, people across all areas of the industry should receive a decent amount of training so that they can stop themselves from encountering cables when doing work underground.

Arc Flash vs. Electric Shock – What’s the Difference?

Understanding the differences between electrocution and Arc Flash injuries is important. Each one requires different protective and preventive methods, such as PPE.

While being electrocuted is bad, it is very different from what happens when you experience an Arc Flash. Electrocution can cause a wide range of injuries, such as tingling in the part of your body where the electric current enters to cause death. Ultimately, depending on the way you are exposed and the voltage, there is a broad spectrum of potential consequences from being electrocuted.

On the other hand, an Arc Flash incident releases a huge amount of thermal energy (heat) as well as a strong blast. Together, this is more of an explosion rather than a simple transfer of electrical energy. As such, the industries of an Arc Flash include things like serious burns, damage from the blast and even sight damage due to the brightness of the event. Other Arc Flash injuries can include:

• Shrapnel injuries from flying debris
• Broken bones, concussion or muscle injuries from the blast or falling
• Hearing loss
• Blindness Flash burns to eyes

Those standing a few metres away can also suffer from the blast, not just the individual in direct contact with the cable.

Preventing Arc Flashes

Avoiding arc flashes from ever occurring requires a combination of cable location training for anyone tasked with finding where any and all cables are coated before any excavation works take place, to a general awareness of the risks that are present.

Good risk assessments, and health and safety workers should be used to create a framework that prevents unnecessary strikes from taking place.

Protective gear and appropriate digging equipment should also be compulsory. For instance, each garment should be designed to offer some level of prediction from Arc Flash incidents.

There’s no denying the threat posed by cable strikes and arc flashes. The best way to stop them from occurring is by being proactive and sensitive from the start of any construction and excavation project.