One of the major causes of arc flash is voltage transients (spikes) from inductive load switching or lightning strikes. The transient may last only microseconds, but it may also carry thousands of amps of energy. Other causes include things as simple as touching a test probe to the wrong surface, worn connections, gaps in the insulation, improperly installed parts, or dust and corrosion that cause resistance heating.
Here are seven safety measures workers can take to reduce the risk of arc flash:
1. Get trained on safe work practices.
NFPA 70E specifies that all qualified and unqualified employees who may potentially be exposed to electrical hazards must undergo training to:
Qualified persons must also receive additional training covering such topics as:
2. De-energize equipment before accessing
3. Conduct regular inspections
Knowing the history of the equipment in your facility is the first step to preventing arc flash. The key to identifying an abnormal reading is to gather baseline readings for especially important components and equipment. Critical components to inspect include electrical connections, insulation, and circuit breakers.
4. Wear arc-rated personal protective equipment (PPE)
Wearing the proper PPE in conjunction with the other safety measures is critical to minimizing injury in the event of an arc flash incident. In order for the PPE to perform effectively, its arc thermal performance rating must meet—or exceed—the thermal energy transfer during the arc flash incident.
5. Select tools rated for the environment
6. Use remote display or wireless test tools
Extend your safety zone with non-contact or wireless test tools. Non-contact test tools allow you to take readings on an energized part without making contact. Wireless test tools enable you to attach the probes or clamp to the measurement target and remove yourself from the arc blast zone to read the results. Some of the most common non-contact and wireless tools for electrical inspections include:
7. Install infrared windows for switchgear inspection
Installing properly certified infrared (IR) windows allows technicians to inspect electrical equipment without removing the panel cover. That makes it easier for companies to comply with NFPA 70E when inspecting switchgear and motors. In selecting IR windows look for:
Arc flash and arc blast are very real dangers in today’s industrial electrical environment. By following best practices, using the proper equipment and staying as far away from energized components as possible you can reduce your risk of those events.
For more information on Electrical Safety, see our online course available at the Fluke eLearning Center.