Understanding Electricity AND SOME PRACTICES.pptx

UNDERSTANDING ELECTRICITY AND SOME SAFETY PRECAUTIONS

1. ELECTRICAL SAFETY FACT SHEET SCIENCE

2. DESCRIPTION Because we use electricity daily, it is easy to become comfortable and fail to recognize the many hazards associated with it. Hazards associated with electricity and electrical devices include fire, arc explosions, burns, electrical shock and death (electrocution). Contact with current from a standard receptacle may be lethal. Understanding some simple concepts can greatly minimize the risks associated with electricity

3. APPROVED ELECTRICAL PRODUCTS Ensure that all electrical devices and components are listed or labeled by a nationally-recognized testing laboratory In the Philippines, the BPS Product Testing Laboratory (BPSTL) and the Lighting and Appliances Testing Laboratory (LATL) are examples of nationally recognized testing laboratories for electricity and electrical products. Electrical equipment that is not listed or labeled, such as that built or modified in-house must be inspected and approved for use by a qualified person who can provide assurance that the equipment is properly constructed and safe for use.

4. GUARDING LIVE PARTS Electrical components including switches, outlets, junction boxes, wire raceways, circuit breaker panels, etc. must be guarded to prevent accidental contact with live electricity. If you observe exposed wiring, please contact your building administrator to have covers installed.

5. GUARDING OF LAMPS Lamps used for general illumination located within seven feet of the floor must have a cage or guard to prevent breakage of bulbs and contact with live electrical parts.

6. EXTENSION CORDS Extension cords may not be used as a substitute for permanent outlets. They may only be used for temporary applications. The cords must be labeled as having been tested by a nationally-recognized testing laboratory and be rated for the load they are supplying. Extension cords may not be connected to one another since the conductors are sized for the specific length of cord. Overheating and fire can occur when multiple cords are connected to one another. Cords may not be run through doorways, windows, holes in walls, floors, ceilings, etc

7. INSPECTION/REPAIR OF CORDS Inspect all cords for missing ground prongs and worn/frayed jacketing or exposed conductors. Cords found to be defective must not be used. Cords should be destroyed and disposed of or repaired/replaced by a qualified electrician. Electrical tape may not be used to repair worn or frayed cords. The outer cord jacket is specifically designed to prevent wear of the inner conductors.

8. POWER STRIP/SURGE PROTECTORS Power strips/surge protectors must have built-in circuit breakers. They must be connected directly to a wall outlet and never be connected to one another or an extension cord. Applied load must be within the acceptable range listed on the device.

9. UNDERSTANDING ELECTRICITY SCIENCE

10. WHAT IS ELECTRICITY? Electricity is the flow of electrons (negatively charged particles) through a conductor. Two main types: Static Electricity (stationary charge, e.g., balloon sticking to hair) Current Electricity (flowing charge, e.g., battery powering a bulb)

11. KEY CONCEPTS: Electrons Voltage (V) Current (I) Resistance (R) move from negative (–) to positive (+) terminals. pushes electrons (like water pressure in a pipe). is the flow rate of electrons (measured in Amperes, A). opposes electron flow (measured in Ohms, Ω).

12. CONDUCTORS Materials that allow electric charges (electrons) to flow easily. Examples: Copper Gold Steel Aluminum Silver (best conductor, used in wires) (used in high-end electronics) (used in power lines) (used in power lines) (used in satellites)

13. INSULATORS Materials that block the flow of electric current. Examples: Rubber Plastic Glass Ceramic Dry Wood (Used in wire coatings, gloves) (Outlet casings, bottle material) (High-voltage insulators) (Fuse boxes, spark plugs) (Non-conductive when dry)

14. HOW ELECTRIC CIRCUITS WORK Open Circuit Closed Circuit

15. HOW ELECTRIC CIRCUITS WORK Power Source Conductors Load Switch

16. MEASURING ELECTRICITY "Electrical pressure" (measured with a voltmeter). Example: AA battery = 1.5V, Car battery = 12V. Flow rate of electrons (measured with an ammeter). Example: LED uses ~20mA (0.02A). Voltage (V) Current (I) Opposition to electron flow (measured with an ohmmeter). Example: A resistor limits current to protect an LED. Resistance (R)

17. OHM’S LAW Voltage = Current × Resistance (V = I × R) If resistance increases, current decreases (for same voltage). What it means: A dimmer switch increases resistance → reduces current → bulb dims. Real-World Example: V I R

18. SERIES VS. PARALLEL CIRCUITS Series Circuit Parallel Circuit

19. SERIES VS. PARALLEL CIRCUITS Series Circuit Parallel Circuit Single path for current Multiple paths If one bulb burns out, all stop working Bulbs work independently Used in Christmas lights (old type) Used in home wiring

20. SPECIAL ELECTRICAL COMPONENTS Component Diode Thermistor LDR Inductor Function Allows current in one direction Resistance changes with temperature Resistance changes with light Stores energy magnetically Example Use LED lights Fire alarms Streetlights Power supplies

21. HOW ELECTRICITY IS GENERATED Solar Panels (sunlight → electricity) Wind Turbines (wind → kinetic → electrical energy) Fossil Fuels (coal, gas) Nuclear (uranium fission → heat → steam → electricity) Renewable Sources Non-Renewable Sources

22. set:nAFTfdTkRLk RESOURCES PAGE