ELC 119R-S Electrical Safety Refresher for Subcontract Electrical Workers

1. 1 ELC 119R-SElectrical Safety Refresher for Subcontract Electrical Workers

2. 2 Outline Introduction Shock and Arc Flash 2 Electrical Hazard Mitigation 3 Technical work documentation (TWD) 4 Safe switching procedures 5 Wrap-Up

3. 3 Introduction ~ 300 workplace electrocutions annually Estimated 20,000 shocks for every electrocution ~ 4000 injuries annually requiring days away ~3600 disabling electrical contact injuries annually 10-15 workers hospitalized daily with electrical burns 4-year average of 23 electrical events at SNL

4. 4 Most Common Electrical Events at SNL Short circuit of energized parts to ground Workers shocked from approaching nearer than a safe distance from exposed live parts Workers shocked from faulty equipment Workers shocked from plugging/unplugging equipment

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7. 7 Effects of Current on the Body

8. 8 Effect of Current Passing Through the Body Current can confuse or damage nerve control centers of lungs and heart Heat damage caused by dissipation of energy- body acts as a resistor.

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11. 11 Factors Affecting Shock Remember Ohm’s Law: E=IR Current: most important factor, though directly determined by voltage and body resistance. Path of current: greater chance for survival if current passes through extremities only Duration of Shock: according to IEEE std. 80, the maximum safe duration can be determined by using: t (seconds) = .116/(V/R)

12. 12 Example If an electrician gets a shock from a 277 volt light fixture, would he/she get “stuck” on the circuit? Let’s assume the worker was sweating and use a resistance value of 10,000 ohms. I =E/R I = 277/10,000 I = .0277 amps or ~28 ma

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14. 14 Example continued Let’s also assume that the path of the current is hand to hand. How long does this person have before the shock could be considered fatal? T = .116/(V/R) T = .116/(277/10,000) T = .116/.0277 T = 4.18 seconds!

15. 15 Voltage Thresholds OSHA set threshold for hazardous energy at 50 volts Hazard from applications lower than 50 are usually thermal not shock: batteries, super capacitors, etc. At levels greater than 600 V, skin is usually penetrated driving resistance down.

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17. 17 Rescuing and Treatment Step 1 – Check to see that the area is safe to enter Step 2 - Call 911 immediately Step 3- Rescue the victim with an insulated device (hot stick, rope, dry wood, etc) Step 4 – Begin CPR Step 5 - Continue resuscitation Step 6 - Get medical attention for the victim

18. 18 II Arc Flash A release of thermal energy from an electric arc by the vaporization and ionization of materials, reaching temperatures up to 35,000 °F. Exposure to these extreme temperatures both burns the skin directly and causes ignition of clothing. (2004 NFPA 70E)

19. 19 Nature of the Arc Arc results from passing of current through air Terminals vaporize and serve as conductive medium for ionized gasses Flash can extend further than 10’ from the source Pressure wave caused by rapid expansion of gases with flying molten materials and shrapnel The blast can destroy structures, and knock workers from ladders or across a room. The blast can rupture eardrums and collapse lungs.

20. 20 Nature of the Arc continued

21. 21 Three Factors Affecting Arc Energy Available short circuit current Duration of the arc Distance from the arc

22. 22 Burns From the Arc First degree: surface only. Skin is usually red and tender Second degree: blistering of the skin. Most painful Third degree: complete destruction of the skin with charring of tissue. Most dangerous –susceptible to infection. Skin can not heal itself.

23. 23 First Degree Burns from a 480 Fault

24. 24 Second Degree Burns from the same 480 Fault

25. 25 Effects of the Arc- Burns

26. 26 Accelerator Flash Incident On October 11, 2004, at approximately 11:15 am, a subcontractor electrician working at an Accelerator Center received serious burn injuries requiring hospitalization due to an electrical arc flash that occurred during the installation of a circuit breaker in an energized 480-Volt (V) electrical panel.

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30. 30 Importance of FR Clothing60/40 blend here

31. 31 From the Type A Investigation… Description of Injuries: Electrician received third degree burns on the face, chest, and legs and second degree burns on the arms, involving approximately 50% of his body. Because of the seriousness of his condition, the Board was not able to interview him.

32. 32 Module 2: Electrical Hazard Mitigation

33. 33 1910 CFR 851 and NFPA 70E All Department of Energy Facilities are contractually required by law follow 10 CFR 851- Worker Safety and Health Protection Plan 851.23(a)(14) requires contractors to comply with NFPA 70E as a baseline. 70E is the industry standard for addressing electrical hazards in the workplace Applying 70E standards nothing more than using integrated safety management

34. 34 TURN IT OFF! Energized work no longer allowed at SNL unless: “de-energizing introduces additional or increased hazards or is infeasible due to equipment design or operational limitations” 70E 110.8.A.1 Most hazards can be controlled by insulating, guarding, or by simply working de-energized

35. 35 Electrically Safe Work Condition First priority is to de-energize Review safety plan Inspect equipment, disconnect energy sources, and lock and tag energy sources. Post barricades and signs to establish the limited approach and flash protection boundaries. Open enclosure, identify shorting devices, and discharge energy-storage devices if applicable. Perform Zero Energy verification Test Complete work When the work is completed, test circuits, remove tools, and test gear, perform final check, and close enclosure NOTE: Equipment is not considered de-energized until locked out and verified

36. 36 Energized Work - provided justification requirements (slide 34) are met Strict requirements addressing worker qualifications: Qualified Person: One who has the skills and knowledge related to the construction and operation of the electrical equipment and installations and has received safety training on the hazards involved (Electrical Safety in the Workplace, 2004). Energized work must be authorized by Senior Manager Facilities Engineering- see your contract Sandia delegated representative (SDR) Shock and Flash Hazard Analyses required. This can be accomplished using the table on slide 44. Remember 2 different hazards- shock and flash

37. 37 Shock Hazard Analysis Required ANYTIME a worker crosses the Limited Approach Boundary to exposed live parts Must determine approach boundaries (Limited and Restricted) and required shock PPE (usually gloves and insulated tools) Shock PPE required ANYTIME a worker crosses the Restricted Approach Boundary

38. 38 Shock Approach Boundaries Limited Approach Boundary (LAB) Level II authorization required Only qualified workers may cross * Boundary must be physically established Restricted Approach Boundary (RAB) No unqualified workers Shock PPE required Shock PPE mainly consists of insulating gloves and tools Refer to slide 44 for LAB and RAB approach distances and required PPE.

39. 39 Flash Hazard Analysis Required ANYTIME a worker crosses the flash protection boundary (FPB) Must determine the Flash Protection Boundary and the PPE required for crossing this boundary PPE and distances determined from table slide 44

40. 40 Arc Flash Protection PPE and flash protection boundary (FPB) in CSSP will match that of arc flash hazard (AFH) label on equipment If the electrical equipment is not provided with an AFH warning label, PPE and FPB in CSSP will be determined using the table in slide 44.

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43. 43 Hazard Risk Categories (HRC) Hazard Risk Above Forty Calories: All equipment identified with a Level V (red) Arc Flash Hazard label Hazard Risk Greater Than 600 volts: Obtain flash hazard analysis. Exception: HRC 2 PPE shall be worn In 15 kV manholes. Head, face and glove protection may be removed during cable terminations if no other work is being performed in the manhole.

44. 44 Boundary and PPE Table

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46. 46 Electro-Magnetic Energy Whenever you have electric power, electric and magnetic fields will be generated. The electric field is often generated by the alternating voltage of the electrical system. The higher the voltage, the greater the electric field. Taken together, electric and magnetic fields are often referred to as electromagnetic radiation. The main effect of exposure to EME is heating of tissue and organs. There are rooftop antennas at Sandia that emit varying levels of EME so contact your ES&H coordinator before approaching them

47. 47 Worker Responsibilities Familiarize yourself with procedures and work plans- CSSP Be aware of your surroundings Obey all warnings signs and regulations Always use proper PPE (slide 44) Stop work if an unsafe and/or unexpected condition arises Consider ALL electrical equipment energized unless locked out and verified de-energized

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49. 49 Planning Your Work Planning is a key element in performing work safely and is the first step in the ISMS process. OSHA and 70E require a job briefing be held before any electrical work operation begins. All personnel involved in the job shall be briefed on the safety concerns, energy source controls and precautions regarding their assignments. Should work conditions change or unanticipated hazards appear, additional briefings should be held. Planning must be documented!

50. 50 Planning Your Work continued Consider ALL hazards When changing a ballast, what hazards are involved besides electricity and working from heights? Is there an asbestos issue? Is the fixture in an area known to have dangerous levels of Beryllium? How about radiation?

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52. 52 Performing Your Work All circuits must be considered energized until LOTO’d and verified de-energized Several events at SNL have been the result of failure to verify de-energized Performance of the 0 energy verification still requires PPE and boundary establishment (slide 44) Do you have to do this hot? Physically establish the limited approach boundary (slide 44) Boundary must keep unqualified workers out of area Boundary must warn workers of the hazards inside the area

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54. 54 Module 2 Conclusion Severe hazards associated with energized electrical work Energized work is now the exception- not the norm- Turn –it-off! NFPA 70E provides sound guidance for electrical safety in the workplace Applying the standard is basic ISMS- identify the hazard, control the hazard Remember there are two primary hazards (shock and flash) that must be analyzed and controlled independently

55. 55 Module 3: TWD Requirements Q: What is considered energized work at SNL? A: Any activity inside the Limited Approach Boundary (LAB) Crossing the LAB for ANY reason must meet the 70E justification requirements of 110.8.A.1 (slide 35) ALL energized work requires a technical work document Why? This should be your first question when asked to work energized.

56. 56 Contract Specific Safety Plan (CSSP) The CSSP is the required technical work document for all energized work at SNL performed by a facilities subcontractor The CSSP must incorporate the required energized work permit elements required in NFPA 70E 130.1B2

57. 57 Content of the CSSP A description of the circuit/part to be worked on and its location Justification of why the work must be performed energized. Remember that some troubleshooting could be accomplished with an Ohm meter. A description of safe work practices to be employed (second person, safety watch, Barriers, etc) Results of the shock hazard analysis (voltage the employee(s) will be exposed to) – slide 44 Determination of shock approach boundaries (LAB, RAB, PAB) using table slide 44

58. 58 Content of the CSSP continued 6. Results of the flash hazard analysis (determination of the Flash Protection Boundary and the caloric exposure based on table slide 44 7. The necessary personal protective equipment- shock and flash Means used to restrict access of unqualified personnel to the area (chains, flagging, signage, etc) Evidence of completion of a pre-job briefing including topics covered- checklist Energized work approvals (workers, Managers, Senior Managers)

59. 59 Insulated Tools Insulated tools, rated for the system voltage, are required when contacting any energized component. Insulated tools should be listed under # 3. Ground hooks shall also be listed here.   If the insulated tool can prevent the user from crossing the restricted approach boundary and flash protection boundary, PPE will not be required (except safety glasses).

60. 60 Module 4 Safe Switching Procedures Three hazards associated with switching breakers or disconnects Shock Explosion Arc flash/blast

61. 61 Shock Rare when switching because cover should be in place. Remember shock boundaries 30,000 non-fatal shocks each year in the workplace… 247 died from electrocution in 2006…down from 251 in 2005.

62. 62 Breaker Explosion Counterfeit Products Sub-standard components No NRTL listing Improper Sizing Improperly rated for available fault current

63. 63 Arc Flash - 2006

64. 64 Operating Breakers and Disconnects Use one hand when possible. For side-handled switches, stand as far away to the side as possible to operate the switch. For panel-mounted breakers, do not stand in front of the panel when operating the breaker. Do not expose unprotected portions of the body/face to the potential blast.

65. 65 Review – Switching Operations

66. 66 Module 4 Conclusion Switching can be hazardous Wear appropriate PPE Obtain AIC and clearing times prior to switching Never switch breakers or disconnects under trip conditions - call facilities Never close a breaker or disconnect if uncomfortable Use Left hand rule to keep body away from disconnect when closing

67. 67 Course Wrap-Up You seldom get a second chance with electricity Most electrical accidents are caused by unseen or unanticipated hazards Take your time! Never deviate from procedures If circumstances or conditions change- STOP and re-evaluate Work on energized equipment is restricted at SNL Maintain tools, test equipment, and PPE Never rely on others for your safety

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