Arc Flash Risk Assessment

Legal Background

The latest edition of EN 50110 – Operation of Electrical Installations – Part 1: General requirements requires employers to carry out Arc Flash Risk Assessments.

Employers Liability

Before engaging in any activities around electrical assemblies, a suitable risk assessment is required that includes the necessary protective measures. 

What is an Arc Flash?

An arc flash (also called flashover) is part of an arc fault, a type of electrical explosion or discharge that is the result of either a low impedance connection from air to ground, or another voltage phase in an electrical system. The arc causes ionisation of the air with temperatures approaching 20,000 degrees Celsius, hotter than the surface of the Sun. In addition, the arc blast that follows, whilst proportional to the local fault level can cause control panels to rupture providing a further significant hazard to employees.

The Assessment Process.

Firstly, a site survey is carried out to determine the characteristics of the electrical equipment. This includes individual fault level studies and determining the required safe arc flash boundary and working distances.

The offsite study using Arc flash calculation software compliant to IEEE 1584:2018 is carried out to determine the individual risks. This provides the incident energy at the required working distance and forms the basis of the selection of the appropriate standard of PPE under IEC 61482-2.