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ELECTRICAL SAFETY SUB GROUP

ELECTRICAL SAFETY SUB GROUP. COMPENSATORY ARC FLASH CONTROLS. Greg Christensen. July 16, 2014. THE PROBLEM. Deferred maintenance and run to destruct policies. Electrical systems not meeting design specifications for operability.

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ELECTRICAL SAFETY SUB GROUP

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  1. ELECTRICAL SAFETY SUB GROUP COMPENSATORY ARC FLASH CONTROLS Greg Christensen July 16, 2014

  2. THE PROBLEM • Deferred maintenance and run to destruct policies. • Electrical systems not meeting design specifications for operability. • Improper or inadequate maintenance can result in increased opening time of the overcurrent protective device, thus increasing the incident energy (Informational Note 1NFPA 70E 2012 130.5 ).

  3. MAINTENANCE REQUIRED NFPA 70E 2004 Article 210.5 “Protective devices shall be maintained to adequately withstand or interrupt available fault current (210.5).” NFPA 70E 2004 Article 225 “Circuit breakers that interrupt faults approaching their ratings shall be tested and inspected in accordance with the manufacturer’s instructions.” NFPA 70E 2012 Article 205.4. Overcurrent Protective Devices “Overcurrent protective devices shall be maintained in accordance with the manufacturers’ instructions or industry consensus standards. Maintenance, tests and inspections shall be documented”

  4. ARC FLASH ANALYSIS Arc flash hazard analysis shall take into consideration the design of the overcurrent protective device, and its opening time, including its condition of maintenance. (source NFPA 70E 2012 130.5 ) • Risk • Arc flash hazard analysis inadequate • Arc rated PPE inadequate • InjurIes due to burns

  5. COMPENSATORY ARC FLASH CONTROLS • Escalate arc analysis • Increase distance from energized circuit parts NOTE: Selection of the specific control is based on feasibility. A combination of controls may be necessary.

  6. ESCALATE ANALYSIS • Escalate arc analysis • incorporate a 2 second clearing time into the arc analysis “Two seconds is a reasonable maximum time for calculations” (Source IEEE 1584, Guide for Performing Arc Flash Hazard Calculations). OR, • Increase PPE using a canned approach

  7. INCREASE DISTANCE • Increase Distance • Use remote actuation device to actuate the OCPD • Operate OCPD that has been maintained upstream of the device to be controlled • Use hot stick or other means to increase distance and thereby reduce incident energy.

  8. IMPROVEMENT Compensatory measures are helping to drive electrical safety improvement • In 2012 an EPM program was initiated: • Technical Engineering Evaluations and PMs were created and institutionalized • Thousands of breakers have been tested and maintained • EPM Program is ahead of schedule

  9. SIDE NOTE While working in Salisbury Pro-Hood 40 cal/cm2 Arc Flash Protection Hoods (Model FH40GY), electrical technicians experienced dizziness and increased respiration rates. • An industrial hygiene investigation was initiated and testing indicated breathing zone O2 concentrations dropping to 18.7% within 20 seconds of donning the hoods without increased activity or level of effort.  • Testing was then performed to determine oxygen and CO2 concentrations during increased activity levels in a controlled environment utilizing a treadmill at 2-2.5 mph with a 2-2.5% incline.  Four tests were conducted and the results indicated O2 levels decreasing to approximately 16% after approximately 5 minutes.

  10. OBJECTIVE Develop a best practice: • COMPENSATORY ARC FLASH CONTROLS FOR CONDITIONS OF INADEQUATE MAINTENANCE

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