Electrical Safety, Subpart K

Transcription

1 SHARP Instructor Training Guide Training Overview: Electrical Safety, Subpart K This guide is designed to assist the instructor with the presentation of the Electrical Safety training materials. Each numbered statement represents a statement of fact or concept that should serve as a takeoff point for elaboration. Instructors should draw upon personal real-world experience for analogies and anecdotal embellishment. The trainees study guide is brief and they should be given a few minutes to read and review it. More information about each statement of fact or concept can be gleaned through its corresponding part or section of Subpart K. Some of those specific sections are referenced below. 1. Ground Fault Circuit Interrupters (GFCIs) must be in place to protect workers from shock on all construction work sites. They are fast acting circuit breaker devices that detect small imbalances in the circuit caused by current leakage to ground, and in as little as one-fortieth of a second, cuts off the power in the circuit. 29CFR (b)(1)(ii) Note: The alternative to GFCIs is an Assured Equipment Grounding Program. It is worth mentioning that almost all new construction sites that provide power to the contractor, provide power that is GFCI protected. Also, portable generators rated 5kW or less are exempt from GFCI requirements if properly wired. 2. GFCIs do not take the place of grounding. Hand tools and extension cords must always have a grounding lug on their male plugs. Only double-insulated tools that are clearly marked as such do not have to have grounding lugs. 29CFR (f)(7)(iv)(C)(6) 3. Electricity is always seeking a path to ground. If you touch conductors that are not insulated, you become part of the circuit and the electricity may go through you to get to ground. Note: It must be emphasized that the very best conductor of electricity is water, and that wet or even damp conditions make the possibility of shock greater. Large amounts of current have been known to arc several feet or more through damp air to a ground source. 4. The longer you are part of an electrical circuit, the more damage is done to your body. The closer the point of entry or exit of electrical current to your heart or brain, the more damage will be done. The overall amount of damage to the body from electrical shock depends on the amount of current, the duration of the shock, and the points of entry and exit of current into and from the body. Note: The total amount of physical damage that can be wrought by electrical shock is dependent on how great the amount of current, how long the shocking connection is, and where the current enters and leaves the body. Many shocks can do both internal damage to the heart and organs and also leave extreme burns that run deep into the tissues. 5. Power tools and extension cords must always be inspected prior to their use. Tools or cords found to be defective must be taken out of service and brought in for repair immediately. 29CFR (b)(1)(iii)(C) Note: Unless immediately removed from the jobsite, tools or cords found to be defective should be rendered totally un-useable by cutting off the male plug. Defective tools and cords that are only placed back in the toolbox will not get serviced as quickly as they might if they are kept on the seat of the truck where the foreman or his designee can remit the defective item to the proper company service entity. 6. Most states and municipalities have statutes that require that crane booms and other aerial equipment maintain a minimum of 10 feet from overhead lines. Note: When using ladders around electrical lines, try to have wooden or fiberglas ladders available. If aluminum ladders are all that are available, use extra caution in placing and securing the ladder.

2 7. A popular myth on construction sites is that extension cords have to have molded ends to comply with OSHA standards. NOT TRUE. Any end that has a form of strain relief and is Underwriter s Laboratories (UL) approved is acceptable. Note: Extension cords on construction sites have to be three conductor type and designed for hard or extra-hard usage. That would include from Table of the ANSI/NFPA, Article 400, types S, ST, SO, and STO. These types would be 12/3 gauge, minimum. 8. Cords that have the outer jacket cut or scraped can be taped and used. The defect that renders a cord unserviceable is when any of the conductors insulation is cut or broken. 29CFR (g)(2)(iii) Note: No. 12 or larger cords can be repaired or spliced but only if done so in a way that the conductors retain their insulation. It requires an intricate repair method that is probably out of the technical realm of any but trained electricians. 9. Tool cords or extension cords that are hot or warm to the touch indicate that too much current for the size of the cord is being used by the tool or tools. Note: Cords that are warm may also be a sign of a tool that is malfunctioning. Sometimes, warm or hot cords can be remedied by taking some tools off the circuit to decrease the load. 10. Remember that electrical short circuits can not only shock and burn people, but can start fires. Note: Electrical fires are Class C fires. They can be fought with a common A-B-C fire extinguisher, but an effort should be made first to cut off the source of power that caused the fire in the first place. If the source is not shut off, the fire can re-ignite easily. Answers to Quiz: 1. B 2. C 3. C 4. D 5. A 6. C 7. C 8. B 9. B 10. B

3 SHARP Safety Training Guide Training Overview: Electrical Safety, Subpart K This guide is designed to assist in the promotion and training of Electrical safety. Each numbered statement represents a statement of fact or concept that should serve to provide you with information you can use to protect yourself against electrical shock or burns. 1. Ground Fault Circuit Interrupters (GFCIs) must be in place to protect workers from shock on all construction work sites. They are fast acting circuit breaker devices that detect small imbalances in the circuit caused by current leakage to ground, and in as little as one-fortieth of a second, cuts off the power in the circuit. 2. GFCI s do not take the place of grounding. Hand tools and extension cords must always have a grounding lug on their male plugs. Only double-insulated tools that are clearly marked as such do not have to have grounding lugs. 3. Electricity is always seeking a path to ground. If you touch conductors that are not insulated, you become part of the circuit and the electricity may go through you to get to ground. 4. The longer you are part of an electrical circuit; the more damage is done to your body. The closer the point of entry or exit of electrical current to your heart or brain, the more damage will be done. The overall amount of damage to the body from electrical shock depends on the amount of current, the duration of the shock and the points of entry and exit of current into and from the body. 5. Power tools and extension cords must always be inspected prior to their use. Tools or cords found to be defective must be taken out of service and brought in for repair immediately. 6. Most states and municipalities have statutes that require that crane booms and other aerial equipment maintain a minimum of 10 feet from overhead lines. 7. A popular myth on construction sites is that extension cords have to have molded ends to comply with OSHA standards. NOT TRUE. Any end that has a form of strain relief and is Underwriter s Laboratories (UL) approved is acceptable. 8. Cords that have the outer jacket cut or scraped can be taped and used. The defect that renders a cord unserviceable is when any of the conductors insulation is cut or broken. 9. Tool cords or extension cords that are hot or warm to the touch indicate that too much current for the size of the cord is being used by the tool or tools. 10. Remember that electrical short circuits can not only shock and burn people, but can start fires.

4 SHARP Electrical Safety Quiz Name: Date: (Circle the letter that best answers the question) 1. GFCI stands for: A. Ground For Construction Industry B. Ground Fault Circuit Interrupter C. Ground Fault Cancel Initiative. D. None of the above 2. What type of tools are not required to have a ground lug on their male plug? A. Power Tools B. Industrial Duty Tools C. Double-Insulated Tools D. Do-It-Yourselfer grade tools 3. Electricity always seeks: A. A path to humans B. A path to insulators C. A path to ground D. A path to motors 4. The severity of an electrical shock depends on: A. The amount of current B. The duration of the shock C. The path of current through the body D. All the above 5. Power tools and extension cords should never be used if: A. They are inspected and found to be defective B. They have been carried by their cord C. Been left out in the rain D. All the above 6. How far, at a minimum, should ladders and cranes be set up from overhead lines? A. 30 Feet B. 20 Feet C. 10 Feet D. 5 Feet 7. The feature of a tool or extension cord that keeps the cord from twisting off inside is called: A. The safety valve B. The safety connector C. The strain-relief boot D. A and C 8. Cords can be repaired if: A. The person doing the repair is a competent person. B. The insulation on the conductors is intact C. The plugs are both in good shape D. Defective cords cannot be repaired. 9. If the cord gets warm or hot on the tool you are using, it means the tool is being overused. A. True B. False 10. One thing you would not expect as a result of an electrical shock would be: A. Internal trauma B. Massive bleeding C. Severe Burn Trauma D. The ignition of a fire

5 SHARP Discussion Leader: Attendance Sheet Electrical Safety Training Location: Date: Discussion Topics / Handouts Reviewed: Electrical SafetyTraining Guide -Printed Name- -Signed Name