Electrical Safety Program Refresher Training

1. Electrical Safety ProgramRefresher Training In Compliance with NFPA 70E, 2009 Standard for Electrical Safety in the Workplace

2. Definition of Hot Work • Any work on electrical equipment, circuits, devices, systems, or any other energized part(s) where an employee is required to deliberately, or could accidentally, place any part of his body, tool or material into or around such electrical devices where the voltage has been deemed to be in excess of 50 volts.

3. Why 50 Volts? • OSHA and NFPA 70E have determined that the threshold for dangerous electrical potential is 50 volts. • WHY? • The average human has 10,000 ohms of resistance in our skin. • Currents of .005 amperes can be fatal. • Ohms law: 50 volts / 10000 ohms= .005 A

4. Study of Electrical Accidents • Study was done base on serious electrical accidents that occurred to professional electricians during the discharge of their professional duties. • An electrical accident was defined as an accident that was caused by contact or close proximity with electrical energy that was discharged in a manner not compliant with the circuit or system’s design.

5. Study of Electrical Accidents • A serious accident was defined as any accident that resulted in 6 months lost time up to and including a fatality. • There were 178 accidents that fell into this category in 1998.

6. Category Break Down Distribution Equipment: 4% Overhead Power Lines: 3% Devices Mounted Below 8’: 31% Devices Mounted Above 8’: 59% Other Accidents: 3%

7. Interesting Statistics • 90% of the accidents occurred while doing every day electrical tasks • 81% of the accidents occurred to electricians with 8 plus years of experience. Ask yourself why the majority of these serious accidents occurred to experienced electricians.

8. The Hazards of Electricity • Electrical Shock • Burns • Arc Blast • Arc Flash

9. Electrical Shock • Short Term Effects • Heart Failure • External Burns • Internal Burn • Cellular Degradation • Autonomic System Failure • Ventricular Fibrillation • Muscle Contractions • Long Term Effects • Nervous system disorders • Heart Damage • Heat Murmur • Brain Chemical Imbalance • Muscle Ticks • Muscle Damage

10. Effects of Current on the Body • Five primary factors affect the severity of the shock a person receives when he or she is a part of an electrical circuit: • Amount of current flowing through the body (measured in amperes). • Path of the current through the body. • Length of time the body is in the circuit. • Contraction position of the heart • Chemical cycle of the body

11. Shock (A) Touch Potential (B) Step Potential (C and D) Touch / Step Potential Current passing through the heart and lungs is the most serious Safety BASICs TM

12. Other Factors • The voltage of the current. • The presence of moisture in the environment. • The general health of the person prior to the shock • The resistance of the person shocked

13. Safety BASICs TM Shock(Resistance Table)

14. Effects of Current • Current level (in milliamperes) and Probable effect on human body • 1 mA Perception level. Slight tingling sensation. Still dangerous under certain conditions. • 5 mA Slight shock felt; not painful but disturbing. Average individual can let go. However, strong involuntary reactions to shocks in this range may lead to injuries. Ventricular fibrillation can occur at this level. • 6-30 mAPainful shock, muscular control is lost. This is called the freezing current or "let-go" range. • 50-150 mAExtreme pain, respiratory arrest, severe muscular contractions. Individual cannot let go. Death is possible. • 1000-4300 mAVentricular fibrillation (the rhythmic pumping action of the heart ceases.) will occur. Muscular contraction and nerve damage occur. Death is most likely. • 10,000 mA Cardiac arrest, severe burns and death almost certain.

15. Energized Work • Is usually preformed on equipment that is not protected by GFCIs. • Even a 15 ampere circuit break will not trip until an overload of 15001 milliamperes is felt in the human body. • Far Beyond the Survival Current.

16. Types of Burns • First-degree burns include only the outer layer of skin. The skin may be red. The skin may also hurt when touched. These are mild burns and usually heal in a few days. • Second-degree burns are deeper and more severe. Blisters may form on the burned area. The skin feels very tender when touched. This burn takes about 2 weeks to heal. • Third-degree burns are the deepest and most dangerous. The skin is tough or leathery. It may look white, brown, black, or red. You may not feel anything when the burned skin is touched

17. Effects of Electrical Burns • Immediate Effects • Pain • Deformity • Nerve Damage • Oral Cavity Damage • Genital Damage • Long Term Effects • Bone Damage • Nerve Damage • Organ Failure • Teeth and Gum Failure

18. Arc Blast and Flash • The third hazard of electricity is the most powerful and dangerous, yet the least talked about in electrical circles. • It was not officially recognized until 1995. • It was not widely studied until 1997. • We now understand it very well, perhaps, too well.

19. Arc Blast • What is an electrical arc. • Current flowing through an area that was once filled with air. • What causes an arc? HEAT • Electrical conductors coming into contact and breaking contact • Electrical conductors coming into close contact • Environmental conditions

20. Effects of Arc Blast • An electrical arc burns at between 20,000 and 32,000 degrees F. • That is twice the center of a nuclear explosion. • That is four times the surface temperature of the sun • The average electrical arc lasts for 4-6 cycles from beginning to end.

21. Expansion of Material • Matter changes shape with temperature as it goes from solid to liquid to gaseous forms. • Water expands 4 times when it goes from liquid to gaseous form. • Copper expands nearly 67,000 times in volume when it goes from solid to gaseous form. • This happens in less than a 10th of a second.

22. Shock Wave • Due to this expansion of material, a shock wave that measures approximately 600 lbs of pressure per square inch moves outward from the arc. • Anyone in this blast area will be moved out of the blast area, forcefully.

23. Cooper Bussman Studies • Cooper Bussman and many other companies have done extensive testing of arc blasts since 1997. • The following slides demonstrate the power of an arc blast in a standard piece of equipment.

24. Electrical Arc Molten Metal 35,000 °F Pressure Waves Sound Waves Shrapnel Copper Vapor: Solid to Vapor Expands by 67,000 times Hot Air-Rapid Expansion Intense Light

25. Personnel Hazards Associated with Arc Flash Heat – Burns & Ignition of Materials Arc temperature of 35,000 ºF Molten metal, copper vapor, heated air Second Degree Burn Threshold : 80 ºC / 175 ºF (0.1 sec), 2nd degree burn Third Degree Burn Threshold: 96 ºC / 205 ºF (0.1 sec), 3rd degree burn Intense Light Damage eyes – cataracts

26. Personnel Hazards Associated with Arc Flash Pressures From Expansion of Metals & Air Eardrum Rupture Threshold 720 lbs/ft2 Lung Damage - Threshold 1728 - 2160 lbs/ft2 Shrapnel Flung Across Room or From Ladder/Bucket

27. IEEE/PCIC & NFPA 70E Arc Flash Hazard

28. Arc Flash Hazard • Following are some of the tests run by IEEE Ad Hoc Safety Committee • All of the devices used for this testing were applied according to their listed ratings

29. Setup Area For Tests • A standard electrical room set up • The test will be performed on a relatively low hazard area. • Not the switchgear • 30A disconnect

30. Close-up of Test Area Arc-Flash

31. 22.6 KA Symmetrical Available Fault Current @ 480V, 3 Phase Test Info 6 cycle STD 640A OCPD Non Current Limiting with Short Time Delay Set @ 6 cycle opening Fault Initiated on Line Side of 30A Fuse 30A RK-1 Current Limiting Fuse Size 1 Starter

32. TEST

33. TEST Arc Blast Begins

34. TEST : Molten Copper

35. TEST: Copper vapor leads to a second blast in gutter

36. TEST: Second blast fire ball

37. TEST: Metal, copper and PVC continue to burn

38. TEST: Room enveloped in toxic smoke

39. 22.6 KA Symmetrical Available Fault Current @ 480V, 3 Phase Results: Test 640A OCPD Non Current Limiting with Short Time Delay Opened in six cycles No Current Limitation Fault Initiated on Line Side of 30A Fuse 30A RK-1 Current Limiting Fuse Size 1 Starter

40. Results: Test Sound 141.5 db @ 2 ft. P1 T2 >2160 lbs/sq.ft T1 > 225 C / 437 F T3 50 C / 122 F > Indicates Meter Pegged > 225 C /437 F

41. How Do We Protect Ourselves • Use the STOP Principal • Stop • Think • Options • Protections

42. Lock Out/ Tag Out • We will discuss methods of protecting you from the hazards of electricity later in the class. • The best method of protection is to de-energize the circuit.

43. The ESP • Now let’s review the Electrical Safety Policy and How it will be used to help reduce the effects of electrical hazards. • The ESP is based on NFPA 70E. The Standard for Electrical Safety in the Workplace.

44. NFPA 70E • First published in 1997 • Published by the NFPA • Updated in 2000, 2004 and 2009. • Now a part of the NEC code making process and formatted in the same manner.

45. OSHA and NFPA 70E • Six states have adopted NFPA 70E as the basis for electrical safety. • The Federal OSHA requirements are in the process of being modified to meet NFPA 70E standards. • NFPA 70E can be used by OSHA compliance officers now as a basis for a citation.

46. Overview of Safety Policy • The policy can be broken into three parts • Administration • Hazard Prevention • Hazard Control

47. Policy Requirements • All employees are required to read the entire policy and make themselves familiar with the requirements of the policy. • Ask your supervisor if you do not understand any of this policy.

48. Policy Overview • In this course we will cover some of the requirements of the electrical safety policy.

49. Personal Protective Equipment • Gloves • Tools • FR Clothing • Double Layered • All Cotton unclothing • Eye protection • Face protection • Ear protection

50. Selection of Equipment • All personal protective equipment shall be selected based on the NFPA 70E charts provided in the electrical safety policy. • You can download this chart from the main module page.