1. Basic Electrical Safety WAC 296-800-280

2. Concerned About Electricity? How many sets of holiday lights do you plug into one extension cord? Do you still use your hot and sparking electric drill? Is your vacuum cleaner’s cord twisted and frayed? Have you installed outlet covers to protect small children’s probing fingers?

3. Rules of Electricity  Electricity travels in a completed circuit  Electricity always travels in the path of least resistance  Electricity tries to travel to ground  Shock occurs when body becomes part of the electrical circuit

4. Substances with very little resistance to the flow of electrical current are called conductors. Examples are metals. Substances with such a high resistance that they can be used to prevent the flow of electrical current are called insulators. Examples are glass, porcelain, rubber, plastic, and dry wood.. How Electricity Works

5. Body’s Resistance Skin offers most of the body’s electrical resistance Increased resistance –Thick and callused skin (foot or hand) –Dry skin Decreased resistance –Thin skin (inner forearm) –Wet or sweaty skin –Broken or abraded skin (scratches)

6. Additional Resistance Gloves Shoes Insulating Mats

7. Grounding The term "ground" refers to a conductive body, usually the earth. "Grounding" a tool or electrical system means intentionally creating a low- resistance path to the earth. When properly done, current from a short from follows this path, thus preventing the buildup of voltages that would otherwise result in electrical shock, injury and even death. Improper grounding

8. Inadequate Grounding (Path Of Ground Missing Or Discontinuous) Am I In Danger? If the power supply to the electrical equipment at your site is not grounded or the path has been broken, fault current may travel through a worker's body, causing electrical burns or death Even when the power system is properly grounded, electrical equipment can instantly change from safe to hazardous because of extreme conditions and rough treatment. Removing the ground pin from a plug to fit an ungrounded outlet not only means your work area is unsafe, but makes the cord unfit for future work where there is grounding.

9. Ground Wire Not Attached A fan connected to a 120-volt electrical system via an extension cord provided ventilation for a worker performing a chipping operation from an aluminum stepladder. The insulation on the extension cord was cut through and exposed bare, energized conductors which made contact with the ladder. The ground wire was not attached on the male end of the cord's plug. When the energized conductor made contact with the ladder, the path to ground included the worker's body, resulting in death. Death due to inadequate grounding

10. Electrical Shock Internal Injuries Excessive electricity flowing through the human body can cause serious damage to internal organs. Resulting medical problems include hemorrhage (or internal bleeding), tissue destruction, and nerve or muscle damage. These internal injuries may not be immediately apparent to the victim or observers; however, left untreated, they can result in death.

11. Involuntary Muscle Contraction Normal muscle contraction is caused by very small amounts of electricity that are created within our bodies. Muscles violently contract when stimulated by excessive amounts of electricity. These involuntary contractions can damage muscles, tendons, and ligaments, and may even cause broken bones. If the victim is holding an electrocuting object, hand muscles may contract, making it impossible to drop the object and prolonging contact with the current. Also, injury or death may result when violent muscle contractions cause workers to fall from ladders and scaffolds or inadvertently strike other objects.

12. Contact with Power Lines Overhead and buried power lines at a construction site are especially hazardous because they carry extremely high voltage. Fatal electrocution is the main risk, but burns and falls from elevation are also hazards. Using tools and equipment that can contact power lines increases the risk. Examples of equipment that can contact power lines: Backhoes Concrete pumpers Cranes Long-handled cement finishing floats Metal building materials Metal ladders Raised dump truck beds Scaffolds Overhead power lines are un-insulated and can carry tens of thousands of volts, making them extremely dangerous to employees who work in their vicinity. Stay at least 10 feet Away from power lines

13. Hazard Control Injuries typically occur when: –Procedures are inappropriate –Procedures are not followed or ignored –Safety systems are circumvent

14.  Avoid accidental starting. Do not hold fingers on the switch button while carrying a plugged-in tool.  Use gloves and appropriate safety footwear when using electric tools.  Store electric tools in a dry place when not in use.  Do not use electric tools in damp or wet locations unless they are approved for that purpose.  Ensure that cords from electric tools do not present a tripping hazard.  Remove all damaged portable electric tools from use and tag them: "Do Not Use."  Use double-insulated tools. Power Tools

15. Hand-held tools manufactured with non-metallic cases are called double-insulated. If approved, they do not require grounding under the National Electrical Code. Although this design method reduces the risk of grounding deficiencies, a shock hazard can still exist. Double insulated marking

16. Portable Power Tools Inspect portable power tools Never use damaged equipment –Tag it out of service –Have it repaired or replaced Never use portable power equipment in wet or damp areas Stop using power tools if they become hot or start sparking

17. Extension Cords Inspect and check for capacity For temporary work only Do not use as a rope to pull or lift objects Should not be fastened with staples or hung over metal hooks or nails

18. Electrical Cord Inspection Deformed or missing pins Damaged outer jacket or insulation Evidence of internal damage If damaged, take out of service until repaired OSHA prohibits using tape to repair electrical cords

19. Circuit Protection Energize or de-energize with appropriate switches, breakers, etc. Do not energize or de-energize with fuses, terminal lugs, or cable splice connections If circuit protection device is tripped— inspect (this may be you last warning)

20. Grounding Equipment Most electrical equipment is designed with a grounding system Do not use equipment with damaged grounding connectors Do not use adapters that interrupt the grounding connection NEVER cut the ground leg (third prong) off of a plug. It is there to protect you!

21. Examples of Prohibited Uses of Flexible Cords Substitute for fixed wiring Run through walls, ceilings, floors, doors, or windows Concealed behind or attached to building surfaces

22. Ground Fault Circuit Interrupters GFCIs reduce the likelihood of fatal shocks Detect small amount of earth current and automatically switch off the power Used with extension cords and portable tools Fuses and circuit breakers protect equipment, not people

23. Summary Electricity will try to reach ground even if it means going through a person Even the “small” voltage from your home can cause serious injury Always inspect power tools and cords and do not use them if damaged Do not attempt to repair electrical equipment unless trained and qualified

24. water + electricity = danger Replace missing outlet covers Strained Power cord Tripping hazard

25. More Information NIOSH – Electrical Safety – Safety & Health Training for Electric TradesElectrical Safety – Safety & Health Training for Electric Trades OSHA Construction eTool – Electrical IncidentsElectrical Incidents DOSH Construction Standard – Electrical RulesElectrical Rules eLCOSH – Basic Electrical SafetyBasic Electrical Safety eLCOSH – ElectrocutionElectrocution eLCOSH – Why GFCIs FailWhy GFCIs Fail eLCOSH – Protection from Electric Shock and Arc FlashProtection from Electric Shock and Arc Flash OSHA Fact Sheet – Working Safely with ElectricityWorking Safely with Electricity