Reducing Arc Flash Risks with Condition Based Maintenance
Every year thousands of electrical workers are injured or even killed while at work. To address this issue, safety and trade organizations around the world are enforcing regulations and standards that ensure workers do not open electrical switchgear for maintenance activities unless it is put into a safe work condition, the proper engineering controls and personal protective equipment (PPE) are used and the appropriate level of safety and equipment training is given to everyone involved in the maintenance operation. In the USA and Canada the National Fire Prevention Association (NFPA) and Canadian Standards Association (CSA) are at the vanguard of driving a cultural change within the electrical maintenance industry. The NFPA 70E /70B and CSAZ 462/463 standards and guidelines provide references for facilities to meet the requirements of workplace electrical safety and outline the best practices for setting up and maintaining a safe and efficient Electrical Preventative Maintenance (EPM) program.
When deciding on an electrical maintenance strategy we first need an understanding on how our electrical distribution equipment fails. A valuable resource can be found by reviewing the failure patterns detailed in the Reliability Centered Maintenance (RCM) engineering framework (see Fig 1). These patterns seem to go against common perceptions that age related failures account for most of the failures that we see in the field; in fact, it is quite the opposite. This type of failure only accounts for 11% of all the failures that we see. The majority of failures are actually due to random failures which account for 89% of system failures, in particular infant mortality which accounts for 68% of all failures dispelling the “Its brand new so it should be OK” myth.