Electrical Safety Lecture 1 PDF

# Electrical Safety ## Lecture 1 ### What is Electricity? Electricity is an invisible phenomenon created by the movement of electrons in a conductor. ### Electrical Material - **Conductor:** A material that contains many free electrons and is capable of carrying an electric current is called a cond...

# Electrical Safety ## Lecture 1 ### What is Electricity? Electricity is an invisible phenomenon created by the movement of electrons in a conductor. ### Electrical Material - **Conductor:** A material that contains many free electrons and is capable of carrying an electric current is called a conductor. Metals and (generally) water are conductors. Gold, silver, aluminum and copper are all good conductors. - **Insulator:** Materials that contain relatively few free electrons are called insulators. Non-metallic materials such as wood, rubber, glass and mica are insulators. - **Fair conductors** include the human body and earth. ### Types of Electricity - **Static electricity:** Electricity that gathers in one place. - **Current electricity:** Electricity that moves from one place to another. ### How does Electricity Work? - Electricity is the flow of electrons around a circuit. - Electrons carry electrical energy from one place to another, creating current electricity, or an electric current. - For an electric current to happen, there must be a circuit. - A closed path, or loop, around which an electric current flows. ### Rules of Electricity - Electricity always tries to travel to ground. - Electricity always travels in the path of low resistance. - Electricity travels in a completed circuit path. - Electricity tries to travel in the shortest path. ### Electricity and Human - A person usually offers a lesser resistance path for the electricity. - The person forms a completed circuit when touching the ground and electricity. - The person forms a shortest path when touching the electricity. ### Where to Start? **SAFETY FIRST!** - Safety starts here. - Think safe. - Work safe. - Be safe. ### Why Electrical Safety is Important? - Electrical hazards can cause burns, shocks and electrocution. - Electrocution is among the most frequent causes of occupational injury or death at workplaces. - Electricity travels in closed circuits, normally through a conductor. - Your body can be a conductor which may mean an electrical shock. ### Why Safety is Required? - **Unsafe Act** - **Safe Act** ### Effects of Electricity on Human Body | Milliamperes | Effect | |---|---| | 1 | Threshold of sensation | | 2 | Mild shock | | 5 | GFCI will trip | | 10 | Cannot let go | | 20 | Muscle contraction | | 30 | Suffocation possible | | 60 | | | 90 | Heart stops beating | | 100 | Breathing stops | | 200 | Severe burns | | 300 | | | 900 | | | 1000 | Will light a 100-watt bulb | It doesn't take much current to cause injury or death. ### Electrical Hazardous What are the hazards of electricity and electrical equipment? - Shock - Electrical arcs and blasts - Rescues - Ground faults - Extension cords - Broken or faulty equipment ### Effects of Electricity on the Human Body #### Electrical Shock - Current passes through the body. - Varied types of effects are faced by the body from tingling sensation to electrocution. - Severity of the shock depends on: - Path of current through the body. - Amount of current flowing through the body. - Length of time the body is in the circuit. - Low voltage does not mean low hazard. ### Effects of Electricity on the Human Body - **5mA-10mA**: Throw off, painful sensation. - **10mA-15mA**: Muscular contraction, can't let go. - **20mA-30mA**: Impaired breathing. - **50mA and above:** Ventricular fibrillation and death ### Types of Injuries Caused by Electric Shock - **Direct injuries** - Electrocution - Electrical shock - Burns - Arc blasts - **Indirect injuries** - Falls ### Electrical Shock | Milliamperes | Effect | |---|---| | 0 | | | 10 | Can just feel it - increased pain | | 20 | | | 30 | | | 40 | Can't let go | | 50 | | | 60 | Severe pain | | 70 | | | 80 | Probably fatal | | 90 | | | 100 | | ### Electric Hazard Causes - Improper grounding - Exposed electrical parts - Inadequate wiring - Damaged insulation - Overloaded circuits - Damaged tools & equipment - Wet conditions - Overhead power lines ### Difference Between Electrical Earthing System and Without Earthing System #### Equipment without Earthing - A diagram shows a person standing near an electrical appliance. The electrical appliance is connected to a transformer, and there are live and neutral wires. The neutral wire is connected to earth. Fault current passes through the human body. #### Equipment with Earthing - A diagram shows a person standing near an electrical appliance. The electrical appliance is connected to a transformer, and there are live and neutral wires. The neutral wire is connected to earth. Fault current passes through the earthing. ### Employee Responsibility - Follow safe work practices. - Make sure lines are de-energized before your work on them. - Wear required PPE. - Alert your co-workers to any unsafe work practices. - Report all problems to your supervisor. - Know what to do in the event of an emergency. - Use electrical tools and equipment that are protected by a GFI. - Review your assignments with your supervisors. - Utilize correct PPE. - Report all problems to your supervisors. - If at all in doubt, ask questions. ### Electrical Qualified vs Unqualified Persons #### Qualified Persons - The standard defines a qualified person as one familiar with the construction and operation of the equipment and the hazards involved those who are permitted to work on or near exposed energized parts. - Whether an employee is considered to be a "qualified person" will depend on various circumstances in the workplace. It is possible and, in fact, likely for an individual to be considered "qualified" with regard to certain equipment in the workplace, but "unqualified" as to other equipment. #### Unqualified Persons - The training requirements contained in this section apply to employees who face a risk of electric shock that is not reduced to a safe level by the electrical installation requirements. - Employees shall be trained in and familiar with the safety-related work practices required to their respective job assignments. ### PPE for Safety - Employees working in areas where there are potential electrical hazards shall be provided with, and shall use, electrical protective equipment that is appropriate for the specific parts of the body to be protected and for the work to be performed. ### How to Protect from Electricity - Follow specialized procedures in wet work areas. - Use lockout/tag out. - Conduct inspections. - Follow assured grounding programs. - Use GFCIs. - Guard energized parts. ### Wet Area - If you touch a live wire or other electrical component while standing in even a small puddle of water, you will get shocked. - Avoid working in wet conditions whenever possible. - Use approved electrical equipment for wet conditions, and do not stand in wet areas when operating electrical equipment. ### How does Electricity Work? #### Voltage - A kind of electrical force that makes electricity move through a wire. - Measured in volts. - The bigger the voltage, the more the current will tend to flow. #### Current - A steady flow of electrons, measured in amperes (or amps). ### Lockout/Tagout - Proper lockout/tagout procedures protect workers from the unexpected start-up of electrical equipment. - These procedures make sure that electrical equipment is de-energized before it is repaired and protect workers against electric shock. ### Inspection - Visually inspect all electrical equipment before use. - Remove any equipment with frayed cords, missing ground prongs, cracked tool casings, etc., from service. ### Assured Grounding Program: - This includes a written program, daily visual inspections, and a method to detect a faulty grounding wire in an extension cord or hand tool. - Grounding gives a stray current somewhere to go and keeps workers from becoming part of the circuit. ### Electrical Grounding - Locating or enclosing electric equipment to make sure workers do not accidentally come into contact with its live parts. - Requires equipment with exposed parts operating at 50 volts or more to be placed where it is accessible only to authorized workers qualified to work with it. ### Safety To Be Followed At Site - **Sign boards/Warning Indications** should be placed wherever necessary. - **Proper PPE** should be used while attending any installation/maintenance/troubleshooting. - **PPE (Personal Protection Equipment)** includes fall protection, arc flash protection, fire rated clothing, gloves, boots, and protective eyewear. - All personnel working on or near PV systems should be trained to recognize hazards and choose the appropriate PPE to eliminate or reduce those hazards. - Always keep the record of assigned tasks, incidents outcome and the person in charge of the site and people who are working at site. - Always have Layout/Route map of the Chemical Plant.