Arc Flash Safety – Distance is your Friend
When I began taking Brazilian Jiu Jitsu (bjj) lessons, I remember my instructor telling me the key strategy in Brazilian jiu jitsu was all about managing the distance from your opponent – either by being safely out of an opponent’s reach (two arm’s length distance) or in the grasp of your opponent. This strategy is intended to reduce the likelihood of receiving damaging strikes from an opponent. But what does Brazilian jiu jitsu have to do with arc flash safety? Good question! With electric arcs, when you double the distance away from the arc source you reduce the incident energy in calories/cm2 to one-fourth (1/4th) the initial incident energy. Listed below are devices that may be used to safely protect workers while: 1. Racking bucket-style circuit breakers; 2. Operating power circuit breakers; and 3. Operation of metal-clad switch gear circuit breaker control switches. A special thanks to CBS ArcSafe for providing me a tour of their Charleston, WV facility.
Bucket Style Circuit Breakers
Some of the worst electric arcs I am familiar with have occurred while qualified employees are racking in bucket style breakers. Racking circuit breakers is a common task performed by electrical workers. Unfortunately, this task is responsible for numerous serious electric arc flash incidents. The main reason is the moving of parts that must be aligned properly to engage the breaker. Many times these mechanisms are not maintained and cause problems. Excessive use of force or broken parts tend to cause the issues that lead an to arc flash. Another cause is a tool left in the breaker when it is being installed, resulting in a short when the breaker is energized. The bottom line is movement of energized parts under strain that are not generally properly checked and maintained. Click here to view an electric arc while racking a bucket-style circuit breaker.
One method of protecting your workers is the use of a remote racking device. A remote racking device allows you to insert/remove a bucket-style circuit breaker far outside the arc flash boundary. There are several manufacturers such as Eaton; CBS; and inoRAC. Click here to see a video demonstration by inoRAC on operation of a remote racking device.
Power Circuit Breakers
Operation of power circuit breaker may be potentially hazardous after operating (close/trip) the circuit breaker after charging the spring with the pump handle. To protect qualified workers while operating these circuit breakers, CBS ArcSafe has a device that allows remote operation.
Operating Metal-Clad Switch Gear Circuit Breaker Control Switch
Our last device is remote operations of metal-clad switch gear control switch. CBS ArcSafe manufactures the Chicken Switch® which allows qualified workers to operate these switches far outside the arc flash boundary.
Summary
As stated previously, when it comes to electric arcs – distance is your friend. The best approach is to conduct a review your facilities existing electrical equipment and identify equipment which may benefit with use of remote operating devices. If you have any questions or comments, please contact me by email or phone: 919.933.5548