Eng. Rose Hasan

 describe the workplace electrical hazards and the importance of safe work practices.  define Personal Protective Equipment and the importance of wearing safety clothes.  define safe procedures for using ladders, scaffolds and tools during Electrical Installation.  identify the different safety signs, and explain their meaning.  identify the different safety signs, and explain their meaning;  5. define the fundamental concepts of electricity such as current,  voltage, resistance, circuit, power, conductors, insulators, AC and  DC;  6. define the concept of ‘circuit’ and differentiate between series and  parallel circuits.  7. troubleshoot faults in simple virtual circuits using the virtual  multimeter and taking into account the safety precautions. Eng. Rose Hasan

 So lets find the hidden dangers !!!!  p.com/electricsafetyworld/index.html p.com/electricsafetyworld/index.html Eng. Rose Hasan

 Why electricity is dangerous?  Electrical Shock  Burns  Explosion Eng. Rose Hasan

 How the electrical shock happens ? › Electrical passing through human body  What does the severity of a shock depends on: › Current (10 mA) › Voltage Eng. Rose Hasan

 A man receives a shock in two cases: Current flows between parts of the body Current flows through body to ground Eng. Rose Hasan

 The severity of a shock depends on: › Amount of current. › The current’s path. › The length of time. Eng. Rose Hasan

 Online Activity › cience/electricity_rules/index.htmlkerala.skoool.in/content/KS3%20LOs/s cience/electricity_rules/index.html Homework Eng. Rose Hasan

 In order to work safely you have to do the following: › Wear safety clothes › Use ladders and scaffolds correctly › Operate tools safely › Practice safe work habits Eng. Rose Hasan

 What is PPE ?  What are the basic pieces of PPE ? › Gloves › Glasses › Shoes › Flame-resistant clothing › Hard hat › Earplugs › Face shield Eng. Rose Hasan

 To access a working area you may need a ladder or a scaffold. But you can’t use them without supervision or training !!!!!!! Eng. Rose Hasan

 Tips to follow when you use a ladder: › Made of wood or fiberglass ( But Why ??? ) Eng. Rose Hasan

 Should be set at a safe angle (Why???) Avoid slipping or falling Eng. Rose Hasan

 How to position the ladder (safe angle)? › Use a simple calculation › W= ¼*h  Find the horizontal distance (w) when the ladder touches the wall at a height (h=20m) ??? › W= ____________ m h W Eng. Rose Hasan

 The ladder must have a firm support. Use a ladder leveler Eng. Rose Hasan

 Tips to follow when you use a scaffold: › Wooden › Wheels must be locked to prevent movement › A ladder must be used to get onto it. Eng. Rose Hasan

 Tips to be used before using electricity: › Switch OFF the power before plugging the power socket. › Change damaged cord Eng. Rose Hasan

 Use Insulated tools when required to work when the power is ON Insulator Eng. Rose Hasan

 Wear safety clothes (PPE).  Turn the power off, and never work on energized equipment unless it is absolutely necessary.  Use proper equipments and tools.  Maintain good housekeeping (Why ?) › Do not leave tools lying around the benches or workshop:  to avoid tripping hazards, and lost tools and materials.  Take precautions to avoid fire (As what ?). Eng. Rose Hasan

Find the 7 deliberate mistakes (Fill in your Table) ! Eng. Rose Hasan

 Colored Signs & Logos  Displayed at the workplace  Provide safety awareness  They must be obeyed strictly  Different types of safety signs: › Warning Signs › Advisory/Safe Condition Signs › Mandatory Signs › Prohibitive Signs › Signs for Fire Safety Eng. Rose Hasan

 Warn of any type of hazards  Triangular yellow with a black border. Eng. Rose Hasan

 Provide information about safe conditions.  They are square / rectangular green signs with a white symbol Eng. Rose Hasan

 Indicate that a specific course of action must be taken  Circular blue signs with a white symbol Eng. Rose Hasan

 Indicate that a certain behavior is not allowed  circular red signs with a black symbol Eng. Rose Hasan

 Shows the location of fire fighting equipment.  They are either square or oblong with a red background.  Examples include: fire alarm control, fire alarm do not switch off! Eng. Rose Hasan

 Identify the following safety signs and indicate the type to which they belong. Eng. Rose Hasan

 Current:  Current is the flow of electrons. › With no voltage applied, there is no current flow. › With more voltage applied, a larger amount of electrons will flow, which means a higher current. › Unit: ampere (A) › Measured instrument: Ammeter. Eng. Rose Hasan

 Current flow in a circuit Eng. Rose Hasan

 Voltage:  The driving force that causes electrons to move through a conductor. › Called also: electromotive force (emf)  unit: of volt (V)  Measured Instrument: A voltmeter Eng. Rose Hasan

 The opposition to the flow of current through the conductor  Unit: ohms (Ω). › Like other forms of friction, resistance is responsible for creating heat and loss of power.  Measured Instrument: Ohmmeter. Eng. Rose Hasan

 There are two types of electric current, depending on the direction of the current:  Direct Current (DC): current flows in one direction only.  Direct Current is provided by batteries and is used in battery operated devices such as flashlights, automobiles,… Eng. Rose Hasan

 Alternating Current (AC): it continually reverses the direction of flow.  This change in direction is represented by the sine wave.  voltage supplied to houses and businesses in the UAE is 230V. Eng. Rose Hasan

AC Circuit Eng. Rose Hasan

 Converts AC voltage from the power lines to a constant DC voltage regulated at various voltage levels. Eng. Rose Hasan

 Power: The electrical power determines how fast a certain amount of energy is consumed by a load.  Unit: Watts, kilowatts (1,000 watts) and megawatts (1,000,000 watts).  Power is calculated using the formula, › P = VI = I 2 R = V 2 /R. Eng. Rose Hasan

 Electrical energy is measured in power- time units  called watt-hours or kilowatt-hours (kWh). 1kWh = 1000 watts power being used for one hour.  i.e: The energy consumed by a 100W lamp that is turned on 5 hours is W = P X t = 100 X 5 = 500 watt-hours. Eng. Rose Hasan

 Conductors : a material that allows current to flow through it easily  Insulators: a material in which current movement is difficult  Eng. Rose Hasan

 A multimeter is used to measure current, voltage and resistance in an electrical circuit.  A Digital multimeter (DMM) provides a digital readout of the measurement quantity.  Some digital multimeters also offer the ability to test some electronic components. Eng. Rose Hasan

 To measure current using a DMM through the resistor circuit must first be broken.  The DMM must be set as an ammeter (the round function switch should be in the DC A position), and it must be connected in series with the circuit Eng. Rose Hasan

 Voltage is always measured relative to some other point in a circuit.  To measure voltage across the resistor, the DMM must be set as a voltmeter (the round function switch points to the DC V position), and must be connected across / in parallel with the component Eng. Rose Hasan

 In a water system, the pathway is the piping, which moves the water from storage to where it is used.  In electrical systems, the wires form the pathway for current to flow.  A simple electric circuit consists of the following elements: › Power Source : For a residence, the electrical generating stations could be considered the power source. However, batteries could be considered as primary power sources. › Conductors : Wires provide a path for the current to travel. › Loads : These are devices through which the electricity produces work. Examples: Lamp and Motor. Eng. Rose Hasan

 These devices include switches, fuses and circuit breakers. Eng. Rose Hasan

 A load is any device that uses an electric current and converts the energy to another form. Loads include the following: Eng. Rose Hasan

 Series Circuit: In a series circuit, only one path is provided for the current to flow. The electricity flows through every device in the circuit, and if one device burns out, the circuit will not function. Eng. Rose Hasan

 Parallel Circuit: The parallel circuit has more than one path available for the current to flow. Each path goes to a load that can operate independently of the other branches and loads in the circuit. If one load, such as a lamp, burns out, the other branches would continue to operate. Eng. Rose Hasan

 Loads such as lamps, heater, or motors may not operate properly in a series circuit, and are therefore usually connected in parallel. Only switches, fuses, and circuit breakers are generally connected in series. Eng. Rose Hasan

 Simutech TEC software/ Edison Eng. Rose Hasan