Protective clothing for electrical professions
Arc faults are considered to be one of the most dangerous electrical hazards in the working environment. With temperatures of more than 10,000 °C, it is rightly feared by members of the electrical professions. In addition to technical and organizational protective measures, special work clothing for electricians is used.
An electric arc occurs when there is a sufficiently high voltage and current density between two electrical conductors of different potentials. The gaseous medium in between is ionized, a plasma is formed and the electrical gas discharge - an explosive flow of current through the air - becomes visible as an arc.
Arc fault protection as multifunctional clothing
If this physical phenomenon occurs due to a short circuit or human error, it is known as an arc fault. If this strikes unprotected persons, there is a risk of severe burns, eye damage due to flashing and further injuries due to the pressure wave or, for example, metal parts shooting around. The specific causes for the occurrence of an arc fault can be very different - ranging from installation faults, damaged insulation or damage caused by rats to tools forgotten in a switchgear.
«Even the highest quality PPE must never be used as an excuse to replace safety regulations.»
The risk of an arc fault can therefore hardly be completely eliminated when working on or in the vicinity of live parts of electrical installations. This applies not only to high-voltage systems, but also to junction boxes or cable distribution cabinets, etc. Despite technical protective equipment, suitable personal protective equipment is essential for electrical engineering personnel in many cases.
Arc flash protective clothing is often offered as multifunctional clothing, in the form of jackets, pants or dungarees, but also as coveralls. The purpose of this multi-standard protective clothing is to protect the wearer from the risks of electric arcs and their consequences, such as flames, heat and splashes of molten metal, and to prevent the clothing from continuing to burn.
Two arc fault protection classes
The requirements for PPE against the thermal effects of an arc fault (PPEgS) are regulated in the international standard EN 61482-2, as are the two underlying test methods. All PPE must be type-tested and have a declaration of conformity. A distinction is made between the two arc fault protection classes 1 and 2, also known as APC 1 and APC 2 (for «Arc Protection Class»). This PPE should not be confused with electrically insulating PPE (in accordance with EN 50286) for protection against electric shocks.
Evaluation in individual cases
The decisive factor on site is that the expected arc energy is safely covered by the choice of protective clothing. Hazard identification with risk assessment may show, for example, that PPE of protection level 1 is sufficient when working on a system that has an effective technical arc fault protection system. The risks must be determined on a case-by-case basis and, if necessary, a balance must be struck between the protective effect and wearing comfort. The relationship between short-circuit current, arc protection classes and protection levels is explained in Directive 407 of the Swiss Federal Inspectorate for Heavy Current Installations (ESTI), as well as information on when which PPE should be used.
Arc fault protective clothing in the form of a jacket and trousers is not sufficient to fully protect people at risk. The face and hands are particularly at risk. A hard hat with visor or protective hood, arc-resistant protective gloves or heat-protective gloves are usually indispensable. Dressing according to the onion principle can also increase the protective effect, e.g. if the undergarments also meet the criteria of APC 1.
No substitute for safety rules!
In addition to suitable PPE, insulating safety tools and work poles help to further reduce the probability of an arc fault occurring. However, one thing must always be clear: Even the highest quality PPE and the best work equipment must never be used as an excuse to replace safety regulations or to shorten prescribed work processes. PPEgS, like all PPE, should be seen as a supplement to technical and organizational steps. Even with PPEgS, it is essential to disconnect and proceed consistently in accordance with the 5 safety rules of electrical engineering.
