The arc box test method is a standardized test used to evaluate the performance of electrical equipment and materials in the presence of an electrical arc. It is also known as the arc resistance test or the arc tracking test. It is the common test method for ARC flash protection in Europe

The test involves placing a sample of the material to be tested inside a box that is filled with a mixture of air and steam. An electrical arc is then generated inside the box, and the sample is observed for signs of damage or degradation caused by the arc.

During the test, the voltage and current are gradually increased until an arc is initiated. The arc is then maintained for a set period of time, typically several seconds, while the sample is monitored for any signs of damage or failure.

The arc box test is used to evaluate the ability of materials to resist arcing and prevent the spread of flames in the event of an electrical fault. It is commonly used to test the electrical insulation properties of materials such as plastics, rubber, and other polymers.

The results of the arc box test are reported in terms of the number of seconds the sample is able to withstand the electrical arc before failing, as well as any signs of damage or degradation observed during the test. This information can be used to select appropriate materials for use in electrical equipment and to help ensure the safety and reliability of electrical systems.

What does “Ka” mean?

Ka” is a unit used to express the magnitude of an electrical fault current, and is often used in the context of arc flash analysis and electrical safety.

In an electrical system, an arc flash can occur when a fault current flows through air between conductors or to ground, generating an intense burst of heat and light that can cause burns, injuries, and damage to equipment.

To calculate the potential hazard of an arc flash, it’s important to determine the available fault current at the point where the arc flash could occur. This is typically expressed in units of amperes (A), and can be used to calculate the incident energy of the arc flash.

The incident energy of an arc flash is the amount of thermal energy that is generated by the arc per unit area, measured in joules per square centimeter (J/cm²). Incident energy is dependent on a number of factors, including the available fault current, the duration of the fault, and the distance from the arc.

Ka is a unit used to express the available fault current in kiloamperes (kA), or thousands of amperes. For example, if the available fault current at a particular location is 20 kA, this means that a fault current of 20,000 amperes could flow through the system at that point.

Understanding the available fault current, expressed in units of kA or other appropriate units, is an important part of conducting an arc flash hazard analysis and implementing appropriate safety measures to protect workers and equipment from the hazards of arc flash incidents.

EN 61482-1-2 garments are certified to two levels, Arc Protection Class (APC) 1 and 2.

APC 1 protects against 4Ka 

APC 2 protects against 7Ka