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

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Presentation on theme: "ELC 119R-S 1 ELC 119R-S Electrical Safety Refresher for Subcontract Electrical Workers."— Presentation transcript:


2 ELC 119R-S 1 ELC 119R-S Electrical Safety Refresher for Subcontract Electrical Workers

3 ELC 119R-S 2 Outline Introduction 1 Shock and Arc Flash 2 Electrical Hazard Mitigation 3 Technical work documentation (TWD) 4 Safe switching procedures 5 Wrap-Up

4 ELC 119R-S 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

5 ELC 119R-S 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

6 ELC 119R-S 5 Module 1: Shock and Arc Flash The passage of electric current through the body from contact with an electric circuit (conductors). Exposure to electrical energy may result in no injury at all or may result in devastating damage or death. Electrocution is death by electrical energy resulting from the passing of a high magnitude electric current through the body 5

7 ELC 119R-S 6 Why Are We Susceptible to Injury by Electric Shock? A.Our highly developed nervous system makes us extremely sensitive to even very small electric currents. B.The passage of current through the body results in heating of tissue Each of these interactions has serious consequences. 6

8 ELC 119R-S 7 Effects of Current on the Body Current ValueEffects < 1 maBarely Perceptible 1-5 maPerceptible shock, reflex actions 5 ma GFCI tripsAccepted as maximum harmless current 6-10 maPainful shock, victim can “let-go” 10-20 maPainful shock, victim can not let go 50-100 maVentricular Fibrillation possible 100-200 maVentricular Fibrillation likely 200 maSevere burns, severe muscular contractions, chest muscles clamp the heart and stop it for the duration of the shock. 833 maCurrent used by 100 watt light bulb

9 ELC 119R-S 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.

10 ELC 119R-S 9

11 10 Unfortunate mouse suffers a fatal phase to phase shock

12 ELC 119R-S 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)

13 ELC 119R-S 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

14 ELC 119R-S 13 Is He/She Stuck? Current ValueEffects <1 maBarely Perceptible 1-5 maPerceptible shock, reflex actions 5 ma GFCI tripsAccepted as maximum harmless current 6-10 maPainful shock, victim can “let-go” 10-20 maPainful shock, victim can not let go 50-100 maVentricular Fibrillation likely 100-200 maVentricular Fibrillation occurs 200 maSevere burns, severe muscular contractions, chest muscles clamp the heart and stop it for the duration of the shock. 833 maCurrent used by 100 watt light bulb YES!

15 ELC 119R-S 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!

16 ELC 119R-S 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.

17 ELC 119R-S 16 Entry and exit wounds

18 ELC 119R-S 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

19 ELC 119R-S 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)

20 ELC 119R-S 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.

21 ELC 119R-S 20 Nature of the Arc continued

22 ELC 119R-S 21 Three Factors Affecting Arc Energy Available short circuit current Duration of the arc Distance from the arc

23 ELC 119R-S 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.

24 ELC 119R-S 23 First Degree Burns from a 480 Fault

25 ELC 119R-S 24 Second Degree Burns from the same 480 Fault

26 ELC 119R-S 25 Effects of the Arc- Burns Arcs have ignited clothing 10’ from the arc and can be fatal when within a few feet

27 ELC 119R-S 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.

28 ELC 119R-S 27 Arc flash 2004

29 ELC 119R-S 28

30 ELC 119R-S 29

31 ELC 119R-S 30 Importance of FR Clothing 60/40 blend here

32 ELC 119R-S 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.

33 ELC 119R-S 32 Module 2: Electrical Hazard Mitigation 1.Plan your work 2.Analyze/identify the hazards 3.Control the hazards 4.Perform the work 5.Improve the process for the next operation

34 ELC 119R-S 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

35 ELC 119R-S 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

36 ELC 119R-S 35 Electrically Safe Work Condition First priority is to de-energize 1. Review safety plan 2. Inspect equipment, disconnect energy sources, and lock and tag energy sources. 3. Post barricades and signs to establish the limited approach and flash protection boundaries. 4. Open enclosure, identify shorting devices, and discharge energy- storage devices if applicable. 5. Perform Zero Energy verification Test 6. Complete work 7. 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

37 ELC 119R-S 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

38 ELC 119R-S 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

39 ELC 119R-S 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.

40 ELC 119R-S 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

41 ELC 119R-S 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.

42 ELC 119R-S 41 Exposed Live Part Limited Approach Boundary (shock) Level II authorization required Only qualified workers may cross – unqualified workers may cross if escorted by qualified worker and made aware of the hazards Boundary must be physically established Flash Protection Boundary Distance and PPE determined from table in slide 42 PPE required of ANYONE inside this boundary Restricted Approach Boundary (shock) No unqualified workers Shock PPE required Shock PPE mainly consists of insulating gloves and tools

43 ELC 119R-S 42 Hazard Risk Categories (HRC) HRC 0: Single phase circuits operating at 50-208 volts HRC 1&2: Three-phase circuits operating between 120 and 600 volts HRC 3&4: Three-phase service entrance equipment and switchgear operating between 120 and 600 volts, excluding those systems with a RED, Level V Arc Flash Hazard label.

44 ELC 119R-S 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.

45 ELC 119R-S 44 Boundary and PPE Table Equipment Class HR C Flash Boundary LAB, RAB Required flash PP Required shock PPE PPE Code 208/240 1-ø 0 4’ 3’ – 6”, contact EWC Class 0 gloves with leather protectors and insulated tools Green 120/240, 277/480 3-ø non service entrance 1, 2 6’ 4’, 1’ EWC + accessories Class 0 gloves with leather protectors and insulated tools Blue 120/240, 277/480 3-ø service entrance 3 Contact FMOC project lead 4’, 1’ ISC Class 0 gloves with leather protectors and insulated tools Yellow 120/240, 277/480 3-ø service entrance 4 Contact FMOC project lead 4’, 1’ ESC Class 0 gloves with leather protectors and insulated tools Orange Equipment labeled greater than 40 calories or 600 volts NA Contact SDR, CO, or PM for assistance Red EWC: FR long sleeve shirt (min arc rating = 8) worn over untreated cotton t-shirt with FR pants (min arc rating = 11, safety glasses Accessories: hard hat w/FR rated face shield, hearing protection, and leather boots or shoes IWC: EWC + accessories + FR coveralls (min arc rating = 25) and double –layer switching hood. ESC: 40-calorie switching suit w/rated hood and gloves, leather boots and shoes.

46 ELC 119R-S 45 Example Arc Flash Labels Level I (HC-0) Label Level II (HC-1 and HC-2) Label

47 ELC 119R-S 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

48 ELC 119R-S 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

49 ELC 119R-S 48 Worker Responsibilities Do NOT perform unjustified energized work Do not wear jewelry when performing energized work Report ALL accidents, regardless of severity to Safety Officer/Supervisor Immediately report to your supervisor, anyone known to be under the influence of drugs or alcohol Be aware of secondary hazards- beryllium, radiation, noise, etc Be responsible for your own safety!

50 ELC 119R-S 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!

51 ELC 119R-S 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?

52 ELC 119R-S 51 Planning Your Work continued The meeting must cover the following questions: – Do I thoroughly understand the job? – Do I thoroughly understand my role in the job? – Am I aware of all the hazards I may encounter? – Am I knowledgeable of all the safety rules and required personal protective equipment that apply to the job?

53 ELC 119R-S 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

54 ELC 119R-S 53 Performing Your Work Wear the appropriate PPE  Shirt must be buttoned and sleeves rolled down  Flash PPE is required when inside the flash protection boundary (slide 44) Crossing the restricted approach boundary requires gloves and insulated tools (slide 44)  Maintain your gloves  Are they out of testing date requirements? Use the right tools for the job  Is you meter rated for the task?  Several events at SNL have occurred due to use of an inappropriate meter Do not deviate from job plan.  If work outside of scope is required stop and re-evaluate with all involved co-workers.

55 ELC 119R-S 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

56 ELC 119R-S 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.

57 ELC 119R-S 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

58 ELC 119R-S 57 Content of the CSSP 1.A description of the circuit/part to be worked on and its location 2.Justification of why the work must be performed energized. Remember that some troubleshooting could be accomplished with an Ohm meter. 3.A description of safe work practices to be employed (second person, safety watch, Barriers, etc) 4.Results of the shock hazard analysis (voltage the employee(s) will be exposed to) – slide 44 5.Determination of shock approach boundaries (LAB, RAB, PAB) using table slide 44

59 ELC 119R-S 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 8.Means used to restrict access of unqualified personnel to the area (chains, flagging, signage, etc) 9.Evidence of completion of a pre-job briefing including topics covered- checklist 10.Energized work approvals (workers, Managers, Senior Managers)

60 ELC 119R-S 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 glasse s).

61 ELC 119R-S 60 Module 4 Safe Switching Procedures Three hazards associated with switching breakers or disconnects  Shock  Explosion  Arc flash/blast

62 ELC 119R-S 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.

63 ELC 119R-S 62 Breaker Explosion Counterfeit Products  Sub-standard components  No NRTL listing Improper Sizing  Improperly rated for available fault current

64 ELC 119R-S 63 Arc Flash - 2006

65 ELC 119R-S 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.

66 ELC 119R-S 65 Review – Switching Operations Disconnect RatingRequired PPE (Hazard Category) Up to and including 60 amps (< 600 volts) HC 0 * >60 up to and including 200 amps (< 600 volts) HC 2 * > 200 amps ( 600 volts Must be analyzed by a qualified person. Contact electrical safety for evaluation. Arc flash labels supersede this table reference slide 44 for specifics

67 ELC 119R-S 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

68 ELC 119R-S 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

69 ELC 119R-S 68 Thanks for Viewing Questions: Greg Kirsch at 845-9497 Mark McNellis at 845-4895 Marc Williams at 845-8795

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