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ELECTRICAL SAFETY SUB GROUP Working Group # 3

ELECTRICAL SAFETY SUB GROUP Working Group # 3. COMPENSATORY ARC FLASH CONTROLS. Greg Christensen. July 18, 2014. WORK GROUP # 3. Sub-group activities Compensatory Arc Flash Controls Normal and N on-normal Breaker O perations Facility Arc Flash Hazards List

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ELECTRICAL SAFETY SUB GROUP Working Group # 3

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  1. ELECTRICAL SAFETY SUB GROUP Working Group # 3 COMPENSATORY ARC FLASH CONTROLS Greg Christensen July 18, 2014

  2. WORK GROUP # 3 Sub-group activities • Compensatory Arc Flash Controls • Normal and Non-normal Breaker Operations • Facility Arc Flash Hazards List • Prioritized Breaker Maintenance

  3. COMPENSATORY ARC FLASH CONTROLS • Improper or inadequate maintenance can result in increased opening time of the over current protection device (OCPD), thus increasing the incident energy to which the worker is exposed. • In cases where maintenance has not been performed in accordance with manufacturers’ instructions or industry consensus standards compensatory arc flash control measures should be deployed.

  4. COMPENSATORY ARC FLASH CONTROLS • Increase Working Distance from energized circuit parts • Increase the level of PPE or add barriers/shielding NOTE: Selection of the specific control is based on feasibility. A combination of controls may be necessary.

  5. INCREASE DISTANCE • Increase Working 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. Note: The incident energy from a potential arc flash source varies by the inverse square of the distance in open air. For example if the working distance is 18 inches, increasing the distance to 36 inches reduces the incident energy to approximately ¼ of the former value.

  6. ESCALATE ANALYSIS Increase the level of PPE or add barriers/shielding a. Escalate arc analysis - incorporate a 2 second maximum clearing time, as applicable, into the arc analysis. Based on escalation, prescribe arc rated clothing and PPE. b. Use arc rated clothing and PPE using the alternative approach c. Install barriers- i.e. shielding, blankets, etc

  7. UPSTREAM DEVICE ANALYSIS • For energized electrical work at a point in a distribution system protected by a breaker that has not been maintained, the incident energy calculated at an upstream breaker that has been maintained may be used for work on or downstream of the non-maintained breaker(s) if certain conditions are met.

  8. ALTERNATIVE APPROACH OPERATION OCPD (NON-MAINTAINED) • No arc flash PPE for single phase systems less than 240 VAC, • PPE rated 4 cal/cm2 for three phase voltages greater than 240 VAC up to 1 KV and, • PPE rated 25 cal/cm2 for voltages 1 KV and above.

  9. ALTERNATIVE APPROACH WORK ON ENERGIZED CIRCUIT PARTS PPE rated for 40 cal/cm2 for work on three phase systems >240 VAC for trouble shooting, zero energy verifications and opening hinged and bolted covers to expose bare circuit conductors and circuit parts.

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

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