CSA Z462 Workplace Electrical Safety, developed by the Canadian Standards Association (CSA), provides a set of requirements for the practical safeguarding of individuals that are exposed to electrical hazards in the workplace. One of the main concerns that this standard focuses on is arc flash and shock along with the preventative measures that should be taken to avoid the harm caused by working unsafely.
The best way to understand the importance of the guidelines provided in CSA Z462 is to first know what an arc flash is, what causes an arc flash, and from these understand the danger it poses:
An arc flash is a sudden release of electrical energy through the air when a high-voltage gap exists and there is a breakdown between conductors. An arc flash gives off thermal radiation (heat) and bright, intense light that can cause burns and other injuries. Temperatures have been recorded as high as 35,000 degrees Fahrenheit. Exposure to these extreme temperatures burns the skin directly and ignites the clothing that you are wearing. High-voltage arcs can also produce considerable pressure waves by rapidly heating the air and creating a blast. This pressure burst, or arc blast, can hit a worker with grenade-like force and send metal droplets from melted copper and aluminum electrical components shooting out at speeds up to 700 miles per hour. Fast enough for the tiny shrapnel to penetrate your body.
An arc flash can be spontaneous, or can result from inadvertently bridging electrical contacts with a conducting object. Other causes may include dropped tools, the buildup of conductive dust, or corrosion.
While great advances are being made to improve equipment design and thereby reduce the number of arc flash incidences, there is still much to be done. Each year, 2,000 workers are admitted to burn centers for treatment of severe arc flash burns.
Source: Electrical Safety Foundation International (ESFI)
Although ESFI only comments on the risk posed by high-voltage gaps, recent studies have shown that it is not just high-voltage installations that are capable of generating arc flash – system voltage as low as 120/208V, fed from a transformer 125KVA or larger, can also produce dangerous arc flash incident.
In Canada, CSA Z462 has been in use since January 2009, and has grown to be endorsed by many provincial health and safety regulatory authorities.
The impact of CSA Z462 is very important to employers, contractors, and individual workers. It addresses serious concerns regarding best practices for safe work, and should be important for both safety and due diligence in any workplace.