Electrical Safety-Related Work Practices, Level I and II Review PDF

Electrical Safety-Related Work Practices, Level I and II Review ​Lesson 1 1. Summarize Introduction to Chapter 1. - Chapter 1 introduces the importance of electrical safety culture, emphasizing how decisions made before and during work exposure to electrical hazards can...

Electrical Safety-Related Work Practices, Level I and II Review ​Lesson 1 1. Summarize Introduction to Chapter 1. - Chapter 1 introduces the importance of electrical safety culture, emphasizing how decisions made before and during work exposure to electrical hazards can reduce or eliminate these hazards. It stresses the need for compliance with safety requirements and understanding the consequences of unsafe practices. 2. What would help encourage workers, contractors, and facility owners to NOT allow energized work? - Increased awareness and understanding of laws, requirements, hazards, true costs, and potential consequences of energized work. 3. Define: according to NFPA 70E - a. Arc Flash Hazard: A source of possible injury or damage associated with the release of energy caused by an electric arc. - b. Ground Fault Circuit Interrupter (GFCI): A device that disconnects a circuit when it detects an imbalance between the current flowing to and returning from the equipment, preventing electric shock. - c. Electrically Safe Work Condition: A state in which electrical conductors or parts have been de-energized, locked out, and verified safe to work on. 4. How can energized work be permitted according to OSHA and NFPA 70 E? Is working on energized circuits, day in and day out, a routine part of the job of an Electrical Worker? - Energized work is only permitted when de-energizing the equipment is infeasible or introduces greater hazards. Routine work on energized circuits is not considered a safe practice. 5. The true cost of an electrical injury or fatality should be considered before deciding that work must be performed on energized equipment. List at least four considerations that determine the true cost of an electrical injury or fatality. - 1. Human life and medical costs. - 2. Loss of production and revenue. - 3. Increased insurance premiums. - 4. Legal and compliance repercussions. ​Lesson 2 6. Why is the extent of injury from electric shock typically not visible? - The extent of injury is often internal, as electric shock affects the muscles, nerves, and organs, which are not visible externally except for entry and exit points. 7. How does thermal energy released in a fault relate to the time it takes to interrupt the fault current? - The longer it takes to interrupt a fault, the more thermal energy is released, increasing the potential for serious burns and equipment damage. 8. What are the four recognized electrical hazards? - 1. Electric shock. - 2. Arc flash. - 3. Thermal burn. - 4. Arc blast. 9. Extensive tests and analysis by industry members have shown that the energy released during an arcing fault is related primarily to what two characteristics of the OCPD protecting the affected circuit? - 1. The time it takes for the OCPD to trip. - 2. The available fault current in the circuit. 10. How many cycles do current limiting OCPDs take to operate? If a fault occurs in the current limiting range, why would this be good? - Current-limiting OCPDs typically operate within half a cycle. This is beneficial because limiting the fault current reduces the energy released during an arcing fault, minimizing damage and hazard exposure. ​Lesson 3 11. What does OSHA identify as negative job-related injury or illness consequences for America’s economy in addition to the direct impact on individual workers? - OSHA identifies the economic consequences as lost productivity, increased workers’ compensation costs, training and replacement of workers, and time spent on investigations after injuries or fatalities. 12. What order of priority are OSHA inspections conducted? - OSHA inspections prioritize based on imminent danger, catastrophes (fatalities or multiple hospitalizations), worker complaints, referrals, and follow-up inspections. 13. Define 1926.417(b) - OSHA 1926.417(b) refers to the requirements for controlling hazardous energy (lockout/tagout) to protect employees from accidental startup or release of stored energy. ​Lesson 4 14. The Occupational Safety and Health Act of 1970 was enacted “to assure… _____.” - “...safe and healthful working conditions for working men and women.” 15. Define 1926.417(b) - OSHA 1926.417(b) requires employers to prevent workers from being injured by energizing circuits or equipment by employing lockout/tagout procedures. 16. Define 1910.333(b)(2)(iv), 1910.333(b)(2)(iv)(A), and 1910.333(b)(2)(iv)(B) - 1910.333(b)(2)(iv): Requires lockout/tagout to prevent electrical equipment from becoming energized during work. - (A): Specifies procedures for verifying that a circuit is de-energized. - (B): Describes actions to ensure the system remains de-energized while work is performed. 17. Define 1910.333(b)(2)(i) - This regulation requires that de-energized electrical equipment must be locked or tagged to prevent accidental startup during maintenance or repair. 18. What are the 8 steps to establish and verify an electrically safe work condition? - 1. Identify all energy sources. - 2. Disconnect all energy sources. - 3. Lock and tag out energy sources. - 4. Verify that equipment has been de-energized. - 5. Ground and test to verify the absence of voltage. - 6. Apply grounding cables, if necessary. - 7. Test electrical parts before contact. - 8. Use appropriate PPE for verification. 19. According to 110.2 are the 8 steps all that is required to consider conductors in an electrically safe work condition? Why? - No. Conductors are only considered electrically safe once all lockout/tagout procedures have been followed, voltage testing has confirmed de-energization, and appropriate grounding measures have been applied. 20. Define 1910.333(b)(1) - This regulation mandates that all electrical parts and equipment must be de-energized before employees work on or near them unless de-energization is infeasible or introduces greater hazards. 21. Define 1910.333(b)(2) - Requires that if de-energizing equipment introduces more hazards, employers must establish alternative protective measures, such as using insulated tools and applying barriers. ​Lesson 5 22. For a building electrical distribution system, where is typically the highest available fault current located? - The highest available fault current is typically located at the service entrance of the building, near the utility transformer. 23. Where can the point-to-point method be used to calculate available fault current? - The point-to-point method is used to calculate available fault current at various points in the electrical distribution system, typically from the service entrance down to distribution panels. 24. What two main factors affect available current downstream from a source on the conductors? - 1. The impedance of the conductors. - 2. The size and length of the conductors. 25. Describe the relationship between available fault current and arcing fault current. - Arcing fault current is generally lower than the available fault current. The relationship is not linear due to the added impedance created by the arc, which reduces current flow. Electrical Safety-Related Work Practices, Level II ​Lesson 1 26. Define: Incident energy - Incident energy is the amount of thermal energy generated during an electrical arc event, measured in calories per square centimeter (cal/cm²), that is impressed on a surface a specific distance away. 27. What is the relationship between the limited approach boundary, restricted approach boundary, and the arc flash boundary? - The limited approach boundary is the distance where shock hazards begin. The restricted approach boundary is closer and requires specific training to cross. The arc flash boundary is the distance at which incident energy equals 1.2 cal/cm², requiring PPE to protect against arc flash burns. 28. Under what 4 conditions is energized work permitted? - 1. When de-energizing would create a greater hazard. - 2. When de-energizing is infeasible due to equipment design or operational limitations. - 3. During troubleshooting or voltage testing. - 4. When proper PPE and work procedures are in place to protect workers. 29. How many chapters and annexes does NFPA 70E contain? - NFPA 70E contains 3 chapters and 18 informative annexes. 30. What are the main three topics of the NFPA 70E chapters? - 1. Chapter 1: Safety-related work practices. - 2. Chapter 2: Safety-related maintenance requirements. - 3. Chapter 3: Safety requirements for special equipment. 31. What requirements in 120 need to be met for conductors to be considered in an electrically safe work condition? - Conductors must be disconnected from all energy sources, locked out/tagged out, tested to verify the absence of voltage, and grounded if necessary. 32. Is NFPA 70E a complete comprehensive program? Why or why not? - No, NFPA 70E is not a complete program. It provides minimum safety requirements and guidelines, but employers must develop a comprehensive electrical safety program tailored to their specific operations and hazards. 33. What things must an electrical safety program identify? - An electrical safety program must identify the hazards involved, the appropriate protective measures (e.g., PPE, procedures), training requirements, and methods to ensure compliance with NFPA 70E and OSHA standards. ​Lesson 2 34. By definition, what are the four electrical hazards? - 1. Electric shock. - 2. Arc flash. - 3. Arc blast. - 4. Thermal burns. 35. Define incident energy analysis. - Incident energy analysis is a method used to calculate the thermal energy released during an arc flash event at a specific distance from the arc source. The results determine the appropriate level of PPE required to protect workers from burn injuries. ​Lesson 3 36. What are the clearing times for OCPDs on Table 130.7(C)(15)(a)? - Typical clearing times for OCPDs on Table 130.7(C)(15)(a) range from 0.5 cycles (for current-limiting fuses and circuit breakers) to 30 cycles (for certain low-voltage power and insulated case circuit breakers). 37. How many different ways can you find to identify if something has an ERMS and how it is activated? - ERMS (Energy-Reducing Maintenance Switch) can be identified by the presence of a dedicated switch or button on the equipment, indicator lights, or via documentation in the system’s electrical drawings or manuals. It is typically activated manually by switching the ERMS on before performing energized work. 38. What are the three common types of circuit breakers and where are they widely used? - 1. Molded case circuit breakers (MCCBs): Commonly used in panelboards and switchboards. - 2. Insulated case circuit breakers (ICCBs): Used in switchboards and motor control centers. - 3. Low voltage power circuit breakers (LVPCBs): Found in switchgear. ​Lesson 4 39. What are the two methods for determining the arc flash boundary and arc flash PPE required? - 1. Incident energy analysis method. - 2. Arc flash PPE category method. 40. When using the arc flash PPE category method, what three conditions of use must be considered? - 1. The maximum available fault current. - 2. The maximum fault clearing time. - 3. The minimum working distance from the arc source. 41. According to 130.5(B), why must the condition of maintenance and/or design of equipment be considered? - Improper or inadequate maintenance can result in increased fault clearing time, which in turn increases the incident energy. Equipment design also affects the reliability and performance of safety measures. 42. Study Table 130.7(C)(15)(a). What types of specifications/parameters are specified for the equipment? - Specifications include equipment type, maximum available fault current, fault clearing time, and minimum working distance required to determine arc flash PPE. 43. Is Table 130.7(C)(15)(a) valid and useful for any and all AC situations for selecting PPE? Why not? - No, Table 130.7(C)(15)(a) is not valid for all situations. It is only applicable when certain parameters, such as fault current and clearing times, fall within the table’s specified limits. For situations outside those limits, incident energy analysis must be used. ​Lesson 5 44. Carefully read all of 110.5(A-M) Electrical Safety Program - The section 110.5 in NFPA 70E outlines the requirements for an electrical safety program, which includes elements like awareness, controls, principles, and training. It emphasizes that a complete program must address electrical hazards, ensure proper documentation, and cover periodic inspection and maintenance. 45. According to OSHA and/or NFPA 70E, how should you proceed if you want to reclose a circuit after protective device operation? - You should investigate the cause of the protective device operation, assess the condition of the equipment, and ensure the issue is resolved. Only after confirming it is safe should the circuit be reclosed, in accordance with proper work practices. 46. In terms of incident energy, what would happen if an OCPD fails to operate as designed or does not operate? - If an OCPD fails to operate as designed, the incident energy would be significantly higher because the fault current would not be interrupted in a timely manner, increasing the risk of arc flash hazards and potentially causing severe injury or damage. 47. What is NFPA 70B and what is it good for? - NFPA 70B is the "Recommended Practice for Electrical Equipment Maintenance," which provides guidelines on preventive maintenance of electrical systems. It is intended to improve equipment reliability, enhance safety, and reduce the risk of electrical failures. ​Lesson 6 48. What are the risk control methods in Table F.3? What are the most and least effective methods? - The risk control methods in Table F.3 of NFPA 70E follow the Hierarchy of Controls, which includes: 1. Elimination (most effective) 2. Substitution 3. Engineering controls 4. Awareness 5. Administrative controls 6. Personal protective equipment (PPE) (least effective)