Republic Act No. 7920 - PDF

**REPUBLIC ACT NO. 7920** February 24, 1995 **REGULATION FOR THE PRACTICE, LICENSING, AND REGISTRATION OF ELECTRICAL ENGINEERS AND ELECTRICIANS** **ARTICLE I** **TITLE AND DEFINITION OF TERMS** Section 1. **Title.** - This Act shall be known as the \"New Electrical Engineering Law.\" Sec. 2....

**REPUBLIC ACT NO. 7920** February 24, 1995 **REGULATION FOR THE PRACTICE, LICENSING, AND REGISTRATION OF ELECTRICAL ENGINEERS AND ELECTRICIANS** **ARTICLE I** **TITLE AND DEFINITION OF TERMS** Section 1. **Title.** - This Act shall be known as the \"New Electrical Engineering Law.\" Sec. 2. **Definition of Terms**. - As used in this Act, the following terms shall mean: **(a)** \"Practice of electrical engineering\" a person is deemed to be in the practice of electrical engineering when he renders or offers to render professional electrical engineering service in the form of: **(1)** Consultation, investigation, valuation and management of services requiring electrical engineering knowledge; **(2)** Design and preparation of plans, specifications and estimates for electric power systems, power plants, power distribution systems including power transformers, transmission lines and network protection, switchgear, building wiring electrical machines, equipment and others; **(3)** Supervision of erection, installation, testing and commissioning of power plants, substations, transmission lines, industrial plants and others; **(4)** Supervision of operation and maintenance of electrical equipment inpower plants, industrial plants, watercrafts, electric locomotives and others; **(5)** Supervision of the manufacture and repair of electrical equipment including switchboards, transformers, generators, motors, apparatus and others; **(6)** Teaching of electrical engineering professional subjects; and **(7)** Taking charge of the sale and distribution of electrical equipment and systems requiring engineering calculations or applications of engineering data. **(b)** \"Electric supply equipment\" is any equipment which produces, modifies, regulates, or controls the supply of electric energy. **(c)** \"Electric plant\" is an establishment or a system for the production and modification of electric energy. **(d)** \"Power plant design\" refers to planning, specifying, coordinating layout of electrical equipment in power plants, substations and the like. **(e)**\"Substation\" [ ] is any building, room or separate place which houses or encloses electric supply equipment connected to transmission or distribution lines and the interior of which is accessible, as a rule, only to properly qualified persons. **(f)** \"Electrical system design\" refers to the choice of electrical systems, including planning and detailing of requirements for protection, control, monitoring, coordination and interlocking of electrical systems among others. **(g)** \"Voltage\" is the highest effective potential difference between any two conductors of the circuit concerned expressed in volts. **(h)** \"Kva\" refers to the installed capacity of an alternating current (A.C.) electric plant or supply equipment, or the connected load of industrial plants, commercial establishments, institutional buildings expressed in kilovolt-amperes. **(i)** \"Kw\" refers to the installed capacity of a direct current (D.C) electric plant on board watercraft expressed in kilowatts. **(j)** \"Utilization equipment\" refers to energy-consuming equipment including motors, heaters, furnaces, light sources and other devices which utilize electric energy, for any purpose. **(k)** \"Industrial plant or factory\" refers to manufacturing assembly plants, including engineering shops, shipyards or other business endeavors where electrical machinery and equipment are installed. **(l)** \"Commercial establishments\" are department stores, supermarkets, shopping malls, office buildings, hotels, theaters, stadiums, condominiums, convention centers, restaurant and the like, used for business or profit. **(m)** \"Institutional buildings\" are school buildings, hospitals, museums, display centers, government buildings and the like. **(n)** \"Watercraft\" is any waterborne unit which is designed and built to have an electric plant. **(o)** \"Electric locomotive\" refers to the power plant mounted on wheels as used in the railroad transportation industry. **ARTICLE II BOARD OF ELECTRICAL ENGINEERING** **ARTICLE III EXAMINATION AND REGISTRATION** 3 types of electrical **(a)** Professional electrical engineer: **(b)** Registered electrical engineer: **(c)** Registered master electrician: **(1)** Technical subjects: **(2)** Philippine Electrical Code, Parts 1 and 2: **ARTICLE IV SUNDRY PROVISIONS RELATIVE TO THE PRACTICE OF ELECTRICAL ENGINEERING** **ARTICLE V TRANSITORY PROVISIONS** **ILLUMINATION DESIGN** **1. Determine Lighting Needs for Each Area** **- Living Room:** Use a combination of ambient, task, and accent lighting. **- Kitchen:** This area requires bright, functional lighting. Use a mix of overhead ambient lighting and task lighting. **- Bedrooms:** Lighting should be soft and relaxing. Use dimmable ceiling lights, bedside lamps, and reading lights. **- Bathrooms:** Bright task lighting around mirrors is essential for grooming. Use moisture- resistant fixtures and ambient lighting for a spa-like feel. **-Hallways and Stairs:** Use recessed lighting, wall sconces, or ceiling fixtures to ensure safe navigation. **-Outdoor Areas:** Include pathway lighting, porch lights, and landscape lighting to enhance safety and aesthetics. Use fixtures that are weather-resistant. **2. Types of Lighting** Ambient Lighting: Provides overall illumination for a space. Examples include ceiling fixtures, chandeliers, and recessed lights. Task Lighting: Focused light for specific tasks such as reading, cooking, or working. Examples include desk lamps, under-cabinet lights, and pendant lights. Accent Lighting: Adds drama by highlighting architectural features or artwork. Examples include spotlights, wall washers, and track lighting. Decorative Lighting: Adds style and enhances the visual appeal of a space, like chandeliers or decorative wall lights. **3. Light Sources and Bulbs** LED Lights: Energy-efficient, long-lasting, and available in a variety of color temperatures. Ideal for all areas. Incandescent Bulbs: Provide a warm glow but are less energy-efficient. Best for decorative purposes. Fluorescent Lights: Good for task and ambient lighting, but less common in residential use due to harsh light quality. **4. Color Temperature and CRI (Color Rendering Index)** Color Temperature: Measured in Kelvin (K), affects the mood of the space. Warm light (2700K-3000K) is relaxing and ideal for living rooms and bedrooms. Cool light (4000K-5000K) is better for kitchens and bathrooms. CRI: A higher CRI (above 80) is preferred as it renders colors more accurately, making spaces look more vibrant and natural. **5. Control Systems** Dimmers: Allow adjustment of light levels to create different moods and save energy. Smart Lighting: Enables control via smartphones or voice-activated systems. Smart bulbs and fixtures can change color temperature and intensity based on time of day or user preferences. Motion Sensors: Useful for hallways, bathrooms, and outdoor areas to automatically turn lights on/off. **6. Energy Efficiency and Sustainability** -Opt for LED lighting as it consumes less energy and has a longer lifespan. -Incorporate natural lighting by maximizing windows, skylights, and glass doors. -Use solar-powered outdoor lighting where possible. **7. Aesthetic Considerations** Fixtures: Choose fixtures that match the architectural style and interior design of the building. Layering: Layer different types of lighting to create depth and interest. Focal Points: Use lighting to highlight focal points in each room, such as artwork, plants, or unique architectural details. **8. Compliance and Safety** -Ensure all lighting fixtures and installations comply with local building codes and standards. -Consider the safety of residents by ensuring adequate lighting in staircases, walkways, and entry points. **To calculate the required lumens per square meter for a room, you can use the following steps** **and formula:** **Example Calculation:** Living Room = 150 lm/m² **Calculate the Total Lumens Required:** Total Lumens Required=20 m2×150 lm/m2=3000 lumens **Determine the Lumen Output of Each Fixture:** Assume we are using LED bulbs with an output of 800 lumens each. Number of Fixtures=3000 lumens/800 lumens per fixture=3.75 **TYPES OF BULBS** **LED Bulbs:** Offer the highest lumens per watt, making them the most energy-efficient choice. **Incandescent Bulbs:** Have the lowest lumens per watt, making them the least energy-efficient. **CFL Bulbs:** Offer moderate efficiency, falling between incandescent and LED options. **Parts of an Electrical Plan** An electrical plan (also known as an electrical drawing or wiring diagram) is a crucial component of construction projects for both residential and commercial buildings. It shows the electrical systems layout, including wiring, outlets, lighting, switches, and other electrical components. Here are the key parts of an electrical plan: **1. Title Block** Project Information: Includes the project name, location, architect, engineer, and drawing number. Scale and Date: Indicates the scale of the drawing (e.g., 1:100) and the date of issue or revision. **2. Legend/Symbols** Electrical Symbols: A list of symbols used to represent different components. Abbreviations: Common electrical terms and their abbreviations used in the drawing. **3. Power Layout** Electrical Outlets: Locations of electrical outlets (standard outlets, GFCI outlets, etc.). Switches: Positions of switches, including one-way, two-way, and three-way switches. Wiring Paths: Lines indicating the routes of electrical wiring, showing how outlets, switches, and fixtures are connected. Panels: The location of the main electrical panel or sub-panels, and circuit breakers. **4. Lighting Layout** Lighting Fixtures: Placement of various light fixtures. Light Switches: Corresponding switches controlling the light fixtures. Circuit Information: Circuit numbers or details indicating which lights are on which circuit. **5. Circuiting and Wiring Details** Circuit Numbers: Indicates which outlets, switches, and fixtures are connected to which circuits in the panel. Wire Types: Types and sizes of wires used for different circuits. Conduit Routes: If required, the paths for electrical conduits and the type of conduit used. **6. Load Distribution** Load Calculation: A section detailing the total electrical load, including individual appliance loads. Breaker Assignments: Information about the size of the circuit breakers for each circuit. **7. Service Entrance** Main Electrical Service: Information about the main service entrance, including the location of the utility meter, service drop, or underground service. Grounding System: Details about the grounding of the electrical system, including grounding electrodes and rods. **8. Special Electrical Components** HVAC Systems: Electrical connections for heating, ventilation, and air conditioning (HVAC) systems. Appliances: Special wiring for large appliances (washer, dryer, oven, etc.). Safety Devices: Locations for smoke detectors, carbon monoxide detectors, and other safety systems. **9. Panel Schedule** Panel Board Layout: Includes a list of all circuits, indicating which room or device each circuit controls. Breaker Size: The rating of the circuit breaker for each circuit. Load Summary: A detailed summary of the electrical loads for each circuit and panel. **10. Electrical Riser Diagram (if applicable)** Vertical Layout: A schematic diagram that shows the vertical distribution of electrical services (useful in multi-story buildings). Main Service Distribution: Shows the connection from the main service panel to various sub-panels or distribution points. The **Philippine Electrical Code (PEC)** outlines standards for electrical design and installation to ensure safety, reliability, and efficiency. When creating an electrical plan based on the PEC, it important to adhere to its guidelines for wiring, equipment, protection, and system design. Here are key standards from the PEC relevant to electrical plans: **1. General Electrical Requirements** Safety: Electrical installations must be done in a manner that protects life and property from electrical hazards such as fire, shock, and overloading. Code Compliance: All electrical plans and installations must comply with the latest edition of the PEC. Qualified Personnel: Only licensed professional electrical engineers or master electricians can prepare and sign electrical plans. **2. Wiring Methods and Materials** Conduits and Cables: Wiring systems must use appropriate materials like **PVC, EMT** (Electrical Metallic Tubing), IMC (Intermediate Metal Conduit), or **RSC** (Rigid Steel Conduit), depending on the environment (e.g., wet, dry, or hazardous). Wire Types: Standard wire types such as **THHN** (Thermoplastic High Heat-Resistant Nylon Coated) for interior wiring. The PEC specifies wire sizes based on the load they will carry. Conductor Sizes: The minimum size for conductors is 2.0 mm² (14 AWG) for general branch circuits, with larger conductors required for higher current loads. **3. Load Calculations** Demand Load: The PEC provides formulas to calculate demand loads for residential, commercial, and industrial buildings. This includes determining the load for lighting, receptacles, appliances, and specialized equipment. Voltage Drop: The PEC limits voltage drop in branch circuits and feeders to no more than 3% for branch circuits and 5% for the total of feeder and branch circuits to ensure efficiency. **4. Protection (Circuit Breakers and Fuses)** Overcurrent Protection: Every circuit must be protected against overcurrent using circuit breakers or fuses. The PEC specifies the correct sizing of overcurrent protection devices based on the wire size and load. Ground Fault Circuit Interrupter (GFCI): Required for areas near to prevent electric shock. Arc Fault Circuit Interrupter (AFCI): Required for bedrooms and other living areas to protect against fires caused by arcing faults. **5. Lighting Requirements** Illumination Levels: Lighting must provide adequate illumination based on room usage. Emergency Lighting: Emergency lighting systems must be provided in public buildingsblike hospitals, schools, and commercial establishments to guide occupants in case of a power failure. **6. Receptacle and Outlet Placement** Outlet Spacing: For residential buildings, outlets should be spaced no more than 3.6 meters (12 feet) apart along walls to minimize the use of extension cords. Height and Accessibility: Outlets should be placed at standard heights, and those in accessible areas (e.g., for persons with disabilities) should meet the accessibility requirements. **7. Grounding and Bonding** Grounding System: A reliable grounding system is mandatory to provide a safe path for electrical faults. Bonding: All metal parts of electrical installations must be bonded together to ensure they are at the same potential, minimizing shock hazards. **8. Service Entrance and Metering** Service Drop: Specifications for overhead or underground service drops from the utility. Overhead conductors should have a minimum clearance of 3.0 meters above residential property. Service Panel Requirements: Main service panels must be easily accessible and properly labeled. **9. Appliances and HVAC Systems** Dedicated Circuits: Appliances like air conditioning units, water heaters, and refrigerators require dedicated circuits to prevent overloading general-use circuits. Air Conditioning: HVAC systems must be installed on circuits sized according to their load demand. **10. Emergency and Exit Power Systems** Standby Power: Hospitals, schools, and other essential services are required to have standby generators or battery systems to provide backup power in case of a power outage. Fire Alarm Systems: The PEC outlines specific wiring and power supply requirements for fire alarm systems, especially in commercial buildings. **11. Hazardous Locations** Classified Areas: The PEC outlines specific installation standards for hazardous locations, such as gas stations or factories dealing with flammable materials. Wiring in these areas must be explosion-proof or meet specific protection criteria. **12. Inspection and Testing** Pre-Installation Inspection: Electrical installations must be inspected by local electrical authorities before walls are closed and after final installation. Testing: After installation, circuits must be tested to ensure proper grounding, polarity, and load distribution before being energized. **13. Panel Schedules and Circuit Layout** Panel Schedule: Electrical plans should include detailed panel schedules showing all circuits, breaker sizes, and loads. Labeling: All circuits in the panel board must be clearly labeled with their respective locations or appliances to ensure safe operation and maintenance. **14. Residential Requirements** General Lighting: A minimum of one lighting outlet must be installed in every habitable room, kitchen, and bathroom. Small Appliance Circuits: At least two 20A circuits are required in kitchens for small appliances, as per PEC guidelines. **Adherence to the Philippine Electrical Code ensures that electrical plans meet national safety** **standards and are approved by local authorities** Below are the general steps and documents needed when applying for an electrical installation permit: **1. Electrical Permit Application** Before any electrical installation can proceed, you must secure an Electrical Permit from the City Engineering Office or the local government unit (LGU). The process usually involves submitting the following documents: Required Documents: Duly Accomplished Electrical Permit Application Form: This form can be obtained from the City Engineering Office. It contains basic details about the project, such as the address, type of installation, and load. Endorsement or Referral Slip: Some LGUs may require an endorsement from the Barangay Office or local authority. **2. Electrical Plans and Drawings** An essential requirement for securing an electrical permit is the submission of detailed electrical plans prepared by a licensed electrical engineer. **Required Components of Electrical Plans:** Site Development Plan: A layout showing the location of the project, including utility poles, meters, and the building. Power Layout Plan: Displays the proposed locations of electrical outlets, switches, fixtures, and appliances. Lighting Layout Plan: Includes the positions of lighting fixtures and associated controls. Riser Diagram: For multi-story or larger buildings, showing the vertical distribution of electrical systems. Single Line Diagram: A diagram showing the electrical distribution from the main panel to different circuits and loads. Panelboard Schedules: Detailed information on the number of circuits, wire sizes, overcurrent protection devices (circuit breakers), and the load for each circuit. Load Calculations: Calculations demonstrating that the electrical design complies with the load capacity requirements of the PEC. These plans must be stamped and signed by a Professional Electrical Engineer (PEE). **3. Building Permit (If applicable)** An electrical permit is usually part of the overall building permit process, so you may need to secure a Building Permit first. The electrical installation should align with the approved construction plans. **Documents for Building Permit:** Architectural Plans (for the overall construction). Structural Plans (if electrical installation involves major works, such as conduit inside walls or ceilings). Sanitary and Plumbing Plans (may be required if the electrical system involves pumps or water heaters). **4. Specifications and Bill of Materials** Electrical Specifications: This document provides details about the materials, wiring, and equipment to be used in the installation, specifying the standards and quality requirements. Bill of Materials (BOM): A breakdown of the quantities, types, and costs of the materials needed for the electrical installation. **5. Electrical Engineer License and PTR** The Professional Electrical Engineer (PEE) or Registered Electrical Engineer (REE)responsible for preparing the electrical plans must submit a copy of their PRC License and Professional Tax Receipt (PTR). **6. Owner /Contractor's Affidavit or Authorization** If the project is being managed by a contractor, an Affidavit of Authorization signed by the project owner authorizing the contractor to carry out the work may be required. **7. Barangay Clearance** In some areas, a Barangay Clearance or Endorsement may be required before processing the electrical permit. **8. Fire Safety Inspection Certificate (FSIC)** In larger buildings or commercial spaces, a Fire Safety Inspection Certificate (FSIC) from the Bureau of Fire Protection (BFP) may be required, ensuring that electrical installations meet fire safety standards. **9. Electrical Inspection Fee** An inspection fee is usually required as part of the electrical permit application. This fee depends on the type of project (residential, commercial, or industrial) and the total electrical load involved. **10. Schedule of Inspection** Once the electrical installation is completed, the City Engineering Office will schedule an inspection to ensure that the installation follows the approved plans and adheres to PEC safety standards. **What the Inspection Covers:** Compliance with the PEC: Ensuring proper conductor sizes, circuit breakers, grounding systems, and protective devices are in place. Correct Installation of Electrical Fixtures and Devices: Inspecting outlets, switches, lights, and panel boards. Proper Labeling: All panel boards, circuits, and breaker labels must be properly indicated. **11. Certificate of Final Electrical Inspection (CFEI)** Once the electrical system passes inspection, the City Engineering Office issues a Certificate of Final Electrical Inspection (CFEI). This certificate is required for the power utility company (such as Meralco) to connect and energize the electrical supply. **12. As-Built Electrical Plans (If Required)** In some cases, particularly for large or commercial projects, As-Built Electrical Plans may be required after the completion of the project. These reflect any changes made during installation that deviate from the original plans. **Additional Considerations:** Temporary Service Permit: If temporary electrical service is required for construction purposes, an additional permit may be needed. Compliance with Energy Efficiency Codes: Some cities may require that electrical systems comply with energy-saving measures, such as the use of LED lighting and efficient wiring systems. **General Checklist for Electrical Permit Application:** 1\. Electrical Permit Application Form 2\. Approved Building Permit (if required) 3\. Electrical Plans and Drawings (signed and stamped by a licensed engineer) 4\. Specifications and Bill of Materials 5\. Engineer's PRC License and PTR 6\. Barangay Clearance (if required) 7\. Fire Safety Inspection Certificate (for commercial/industrial projects) 8\. Inspection Fee 9\. Schedule of Inspection 10\. Certificate of Final Electrical Inspection (CFEI) **ELECTRICAL DEVICES AND EQUIPMENT** A kilowatt-hour meter (kWh meter) is a device used to measure the amount of electrical energy consumed by a residence, business, or electrical device. The unit of measurement, the kilowatt-hour (kWh), represents the energy used when one kilowatt of power is consumed for one hour. **Key Functions:** Measuring Electricity Usage and Billing **How It Works:** 1\. Power Flow 2. Counting Energy Usage 3. Display: **Types of Kilowatt-Hour Meters:** 1\. Analog Meters: Older models that use mechanical dials and a spinning disc to measure consumption. 2\. Digital Meters: Newer models that display energy usage on a digital screen. 3\. Smart Meters: Advanced meters that transmit real-time data to both the utility company and the user, providing more detailed usage information. **Kilowatt-hour meters are critical for ensuring accurate electricity usage monitoring and fair billing**. An **analog kilowatt-hour meter** is a mechanical device used to measure the amount of electrical energy consumed by a household, business, or other establishment. **Key Components:** 1\. Spinning Aluminum Disc 2. Electromagnets 3. Rotating Dials 4. Gear Mechanism **How It Works:** Energy Flow: As electricity passes through the meter, it creates a magnetic field in the electromagnets, causing the aluminum disc to spin. Proportional to Usage: The speed of the disc is proportional to the amount of electricity being used. Cumulative Reading: The dials track the total amount of electricity used in kilowatt-hours. **Advantages:** Durable and Simple Operation **Disadvantages:** Manual Reading, Less Accurate and Limited Data A **digital kilowatt-hour meter** is an electronic device used to measure and display the amount of electrical energy consumed by a household, business, or electrical device. **Key Features:** 1\. Digital Display 2. Microprocessor 3. No Moving Parts **How It Works:** Measurement: Digital meters continuously measure the flow of electrical current and voltage in the circuit, then use this data to calculate the amount of energy consumed (in kWh). Data Storage: The meter stores cumulative electricity consumption digitally, allowing it to retain data even during power outages. Real-Time Monitoring: Some digital meters also provide real-time energy consumption data, which helps users monitor their electricity use more closely. **Advantages:** 1\. Greater Accuracy2. Easier to Read3. Advanced Features: 4. Remote Reading: **Disadvantages:** Cost and Power Consumption **Types of Digital Kilowatt-Hour Meters:** 1\. Standard Digital Meters: These provide a digital display of energy use but may still require manual readings. 2\. Smart Meters: A more advanced form of digital meter that automatically sends usage data to the utility company and often offers real-time data for the consumer. **Benefits for Consumers:** Better Usage Awareness: Consumers can track their energy use more easily with clear digital readings. More Detailed Data: Some digital meters provide additional data, such as peak usage times or voltage fluctuations, allowing users to optimize energy consumption and potentially lower bills. A **smart kilowatt-hour meter** (commonly known as a smart meter) is an advanced type of digital meter that records and transmits detailed electricity usage information in real-time to both utility companies and consumers. **Key Features:** 1\. Two-Way Communication 2. Real-Time Data 3. Remote Reading 4. Time-of-Use Pricing **How It Works:** 1\. Energy Measurement: Like traditional meters, smart meters measure the amount of electricity used in kilowatt-hours (kWh). 2\. Data Transmission: The meter transmits the recorded data to the utility company through wireless communication. 3\. Bidirectional Flow: Smart meters can track electricity flowing both into the property (from the grid) and out of the property (from sources like solar panels, if applicable), making them useful for distributed energy systems. 4\. Real-Time Feedback: Many smart meters are connected to in-home displays or online dashboards where users can monitor their consumption and costs in real-time. **Advantages:** 1\. Accurate and Timely Billing 2. Energy Savings 3. Dynamic Pricing 4. Remote Services 5. Integration with Renewable Energy **Disadvantages:** 1\. Privacy and Security Concerns 2. Installation Costs 3. Health Concerns **Key Functions:** 1\. Power Distribution: The panel board distributes electrical power to various circuits in the house, each serving different areas or appliances (e.g., lighting, outlets, HVAC systems). 2\. Circuit Protection: It contains circuit breakers or fuses that automatically cut off power to a circuit if there is an overload or short circuit, protecting the home from electrical fires or damage. 3\. Main Disconnect: The panel usually has a main breaker that can shut off all power to the house in an emergency or for maintenance. **Components of a Residential Electrical Panel:** **1. Main Breaker:** o This is the central control for the entire electrical panel and can shut off power to the entire house. It also protects the entire electrical system from excessive electrical current. o The main breaker is typically rated between 100 to 200 amps for most homes, depending on the power needs of the household. **2. Bus Bars**: o These are metal strips inside the panel that carry the electrical current. There are two types: Neutral Bus Bar: Connected to the neutral wire, providing a return path for electrical current. Grounding Bus Bar: Connected to the grounding wire, providing a safe path to ground for electricity in case of a fault. **3. Circuit Breakers:** o Each individual circuit in the house is protected by its own circuit breaker, which is connected to the bus bars. Circuit breakers \"trip\" to cut off power when the current exceeds the safe limit for the circuit (typically 15 or 20 amps for standard household circuits). **o Types of Circuit Breakers:** Single-Pole Breakers: Used for standard 120-volt circuits (lighting, outlets). Double-Pole Breakers: Used for larger 240-volt appliances (HVAC systems, electric stoves, water heaters). **4. Sub-Panels (if applicable):** o Sub-panels allow for additional circuits and are common in larger homes or detached buildings (garages, workshops). **5. Service Entry:** o The service entry cables deliver electricity from the utility company to the panel. These cables are typically connected to the main breaker. **Types of Residential Electrical Panels:** **1. Main Breaker Panels:** o The most common type of panel, which contains the main breaker along with individual circuit breakers. o It provides both circuit protection and a main disconnect. **2. Main Lug Panels:** o This type does not have a main breaker. Instead, it is connected to a separate disconnect switch (used in some configurations with external main breakers or sub-panels). **3. Sub-Panels:** o Smaller panels that are fed by a breaker in the main panel and used to extend the circuit capacity in different areas of a home or property. **Installation Considerations:** 1\. Location 2. Code Compliance 3. Amp Rating **Safety Features:** 1\. GFCI (Ground Fault Circuit Interrupter) Breakers: o These are special circuit breakers designed to shut off power if a ground fault is detected. Commonly used in kitchens, bathrooms, and outdoor areas where water is present. 2\. AFCI (Arc Fault Circuit Interrupter) Breakers: o These breakers protect against arc faults, which are unintended electrical discharges that can cause fires. They are typically required in bedrooms and living areas. **Summary:** A residential electrical panel board is the heart of a home\'s electrical system, distributing power safely to various circuits while providing protection against overloads and faults. Ensuring that your panel is up to date, properly installed, and sized appropriately for your home\'s needs is crucial for both safety and efficiency. **What is NEMA 3R?** NEMA 3R is a standard rating established by the National Electrical Manufacturers Association (NEMA) that defines the protection level of electrical enclosures, particularly against environmental hazards. A NEMA 3R-rated enclosure is designed to protect electrical components (such as wiring, circuit breakers, or transformers) in both indoor and outdoor environments. Key Features of NEMA 3R Enclosures: 1\. Protection Against Rain and Snow: A NEMA 3R enclosure is constructed to prevent rain, sleet, snow, and external ice formation from entering or damaging the electrical components inside. 2\. Ventilation: These enclosures often have ventilation to prevent condensation inside, which is crucial for outdoor applications. 3\. Corrosion Resistance: Many NEMA 3R enclosures are made of corrosion-resistant materials (like stainless steel or coated metal) to withstand outdoor exposure. **Key Protection Levels:**  Solid Object Protection: It protects against solid foreign objects, like dirt or debris, but not dust-tight (which would require a higher NEMA rating).  Rain and Snow Protection: It provides protection against water, especially rain or snow, and prevents water from dripping or splashing into the enclosure.  Ice Formation: NEMA 3R enclosures can resist ice formation on the exterior, ensuring they function even in freezing conditions. **Common Applications:** 1\. Outdoor Electrical Panels: Often used for residential or commercial electrical panel boxes installed outside. 2\. Meter Boxes: Utility meter boxes mounted outdoors to protect electrical meters. 3\. HVAC Equipment: Protecting control boxes and electrical components in outdoor HVAC systems. 4\. Lighting Controls: Outdoor lighting controls that need protection from weather elements. **Comparison with Other NEMA Ratings:**  NEMA 1: Designed for indoor use and provides protection against dust and light.  NEMA 4: More robust than NEMA 3R, protecting against water from hoses, splashing, and severe weather, making it suitable for harsher outdoor environments.  NEMA 3R vs. NEMA 3: Both protect against outdoor conditions like rain and snow, but NEMA 3 enclosures provide added protection against wind-blown dust. **In Summary:** A NEMA 3R enclosure is suitable for outdoor and indoor use, offering protection from rain, snow, and ice, making it ideal for environments exposed to weather without requiring more expensive, fully weatherproof designs like NEMA 4. **What is an electric circuit breaker?** An electric circuit breaker is a safety device designed to automatically stop the flow of electricity in an electrical circuit if it detects an overload, short circuit, or another fault condition. Its primary function is to protect electrical systems, appliances, and people from electrical hazards like fires and damage to equipment by interrupting excessive current flow. **Key Functions:** 1\. Overload Protection 2. Short Circuit Protection 3. Manual Control: **How It Works:** 1\. Normal Operation 2. Detecting a Fault 3. Tripping 4. Resetting **Types of Circuit Breakers:** **1. Standard Breakers:** o Single-Pole Breakers: Used in residential wiring for standard 120-volt circuits (e.g., outlets, lighting). These breakers protect one \"hot\" wire and handle 15 to 20 amps. o Double-Pole Breakers: Used for 240-volt circuits in the home, such as for large appliances like dryers and HVAC systems. These breakers control two \"hot\" wires and typically handle 30 to 60 amps. **2. GFCI (Ground Fault Circuit Interrupter) Breakers:** o These breakers protect against ground faults. **3. AFCI (Arc Fault Circuit Interrupter) Breakers:** o AFCIs detect dangerous electrical arcs (sparks), which could lead to electrical fires. 4\. High-Voltage Breakers: o These are used in industrial or utility applications to protect high-voltage systems. **Components of a Circuit Breaker:** 1\. Switch: Allows manual control of the breaker to turn circuits on and off. 2\. Contacts: Metal plates that connect or disconnect to complete or break the circuit. 3\. Trip Mechanism: A mechanism, often thermal or electromagnetic, that triggers the breaker to trip when excessive current is detected. o Thermal: Uses a bimetallic strip that bends and trips the breaker when it heats up due to excessive current. o Magnetic: Uses an electromagnet that pulls the switch open when it detects an overload. **Why Circuit Breakers Are Important:** Safety: They prevent electrical fires and protect against electrical shocks by interrupting dangerous electrical faults. Protection of Equipment: Circuit breakers protect appliances and electronic devices from damage caused by power surges or faults. Convenience: Unlike fuses, which need to be replaced after they blow, circuit breakers can be reset after tripping, making them more convenient and cost-effective for long-term use. **In Summary:** An electric circuit breaker is a vital safety device in any electrical system, preventing excessive current from damaging circuits, appliances, and structures. By tripping when necessary and allowing manual control of circuits, they protect both electrical infrastructure and the people who use it. **What is electrical switches?** An electrical switch is a device that controls the flow of electricity within a circuit by either opening (turning off) or closing (turning on) the circuit. **Key Functions:** 1\. Control of Electrical Devices: A switch enables users to turn electrical devices on or off by opening or closing the circuit. 2\. Manual or Automatic Operation: Most switches are manually operated, but some can be automated, using sensors or timers. **How an Electrical Switch Works:** Closed Circuit (ON) and Open Circuit (OFF) **Types of Electrical Switches:** 1\. Toggle Switch: Operated by flipping a lever up or down to open or close the circuit (e.g., light switches). 2\. Push Button Switch: Activated by pressing a button. on devices. They can be momentary (only on when pressed) or maintained (on/off with each press). 3\. Rocker Switch: Similar to a toggle switch, but instead of a lever, a flat surface rocks back and forth to open or close the circuit. 4\. Dimmer Switch: Allows variable control of the electrical current, enabling the user to adjust the brightness of lights. Some dimmer switches use a dial or sliding control. 5\. Rotary Switch: Operates by turning a knob that can have multiple positions to control different circuits or settings (e.g., in fan speed control or audio equipment). 6\. Slide Switch: Moves a slider back and forth to control the circuit, commonly found in smaller electronic devices. 7\. Proximity Switch: Detects the presence of an object (without physical contact) and activates or deactivates the circuit. Often used in automatic lighting systems. 8\. Limit Switch: Used in industrial applications, limit switches are activated when a mechanical part reaches a certain position. They are common in machinery and control systems. 9\. Selector Switch: Allows a user to choose between different circuits or functions, often found in equipment with multiple operating modes. **Specialized Switches:** 1\. Three-Way Switch: Used to control a single device (like a light) from two different locations. 2\. Four-Way Switch: Allows control of a device from three or more locations. 3\. Pressure Switch: Activated by pressure changes (often found in hydraulic or pneumatic systems). 4\. Float Switch: Used to detect liquid levels in tanks or reservoirs and control pumps or alarms. **Switch Construction:** 1\. Contacts: Switches contain two conductive parts, known as contacts. When the switch is on, the contacts are touching, allowing electricity to flow. When the switch is off, the contacts are separated, breaking the circuit. 2\. Actuator: The part of the switch that is physically manipulated by the user (such as a toggle lever, push button, or rotary knob). 3\. Housing: The external casing that holds the internal components, typically made from plastic or metal, to provide insulation and protection. **Applications of Electrical Switches:** Lighting Control Appliance Operation Machinery Security Systems **In Summary:** An electrical switch is a simple yet essential device used to control the flow of electrical current in a circuit. By opening or closing the circuit, switches allow users to safely and efficiently control electrical devices, from basic lighting to complex industrial systems. They come in many types and designs, each tailored to specific applications. **What is an electrical convenience outlet?** An electrical convenience outlet, commonly referred to as a power outlet or receptacle, is a device installed in walls, floors, or other surfaces that allows easy access to electricity for powering appliances, electronics, and other electrical devices. It provides a safe and convenient way to plug in devices, eliminating the need for direct connection to electrical wiring. **Types of Electrical Outlets:** 1\. Standard Two-Prong Outlet: These lack grounding and are mostly found in older homes, though they are less common today due to safety concerns. 2\. Three-Prong Outlet: The third prong is for grounding, which provides added safety against electrical shock. 3\. GFCI (Ground Fault Circuit Interrupter) Outlet: It shuts off the electrical current if it detects a ground fault (like water contact or a current imbalance). 4\. AFCI (Arc Fault Circuit Interrupter) Outlet: Designed to prevent fires caused by electrical arcing 5\. USB Outlets: Modern outlets that include built-in USB ports for charging devices like phones and tablets without needing a separate adapter. 6\. 240-Volt Outlet: These outlets are larger and designed to supply higher voltage for devices with greater power needs. **Where Electrical Convenience Outlets Are Used:** 1\. Residential Homes 2. Commercial Buildings 3. Outdoor Areas **Safety Considerations:** 1\. Grounding: Modern outlets with three prongs include grounding for safety, ensuring that any stray electrical current is directed to the ground rather than causing a shock. 2\. GFCI Protection: These outlets prevent electrical shock by quickly shutting off power when a ground fault is detected. 3\. Tamper-Resistant Outlets: These outlets have built-in shutters that block the insertion of foreign objects, making them safer for homes with children. They are required by code in many new homes. **In Summary:** An electrical convenience outlet is a crucial component of modern electrical systems, providing a safe and easy way to access power for a wide range of devices and appliances. They come in various types, including standard, GFCI, AFCI, and specialized outlets for higher power needs, offering different levels of functionality and safety depending on the application. **What is an electrical lamp and receptacles?** An electrical lamp refers to any device that produces light when powered by electricity. The term typically refers to light bulbs, but it can also encompass complete lighting fixtures designed to house bulbs and provide illumination. **Types of Electrical Lamps:** 1\. Incandescent Lamp: The traditional light bulb, which produces light by heating a tungsten filament until it glows. 2\. Fluorescent Lamp: Produces light through the excitation of mercury vapor inside the bulb, which emits ultraviolet light. 3\. Compact Fluorescent Lamp (CFL): A smaller, energy-efficient version of a traditional fluorescent lamp. 4\. Light Emitting Diode (LED) Lamp: An energy-efficient, long-lasting lighting option that uses semiconductor technology to produce light. LEDs are highly efficient and durable. 5\. Halogen Lamp: A type of incandescent lamp that contains a small amount of halogen gas, which increases efficiency and lifespan compared to traditional incandescent bulbs. 6\. Smart Lamps: Modern lamps that can be controlled remotely via apps or voice commands. They often use LED technology and are integrated with smart home systems. **Components of a Lamp** Base, Bulb, Socket, Housing **Electrical Receptacle (Outlet):** Receptacles provide the point of connectionnbetween the electrical system in a building and the devices that need power. **Types of Electrical Receptacles:** 1\. Standard Receptacle: The typical two- or three-prong outlet found in most homes and businesses. 2\. GFCI (Ground Fault Circuit Interrupter) Receptacle: These outlets are designed to protect against electric shock by quickly cutting off the power if they detect a ground fault. They are required in areas prone to moisture, like bathrooms, kitchens, and outdoor locations. 3\. AFCI (Arc Fault Circuit Interrupter) Receptacle: Designed to detect and interrupt arc faults, which are dangerous sparks that can cause electrical fires. 4\. 240-Volt Receptacle: Used for high-power appliances such as ovens, dryers, and air conditioning units. 5\. USB Receptacle: A modern outlet that includes built-in USB ports, allowing you to charge devices like smartphones and tablets without needing an adapter. 6\. Weatherproof Receptacles: Used for outdoor applications, these outlets are covered to protect them from moisture and other environmental hazards. **What are the electrical boxes?** Electrical boxes are enclosures used to house and protect electrical connections and components within a building\'s electrical system. **Types of Electrical Boxes:** **1. Electrical Outlet Boxes:** Purpose: Designed to house electrical receptacles (outlets) and their connections. Types: Single Gang Box: Holds one receptacle or switch. Double Gang Box: Holds two receptacles or switches side by side. Triple Gang Box: Accommodates three or more devices. **2. Switch Boxes:** Purpose: Used for mounting light switches or other control devices. Types: Similar to outlet boxes but specifically sized and shaped for switches. 3\. Junction Boxes: Purpose: Used to join multiple electrical wires or cables. They provide a location for splicing wires and making connections. Types: Standard Junction Box: Used for general splicing and connections. Octagon Box: Often used for ceiling-mounted light fixtures. 4\. Circuit Breaker Panels (Electrical Panels): Purpose: Enclose and protect circuit breakers or fuses. These panels distribute electrical power to different circuits throughout a building and provide overcurrent protection. Types: Main Breaker Panels: Contain the main breaker switch and individual circuit breakers. Sub-Panels: Smaller panels connected to the main panel, used to distribute power to different areas. **5. Weatherproof Boxes:** Purpose: Designed for outdoor or damp environments to protect electrical connections from moisture and other environmental conditions. Types: Weatherproof Outlet Box: Often has a cover to protect the outlet from rain and snow. Weatherproof Junction Box: Used for connections exposed to the elements. **6. Recessed Boxes:** o Purpose: Installed flush with the wall surface, allowing electrical devices to sit even with or slightly below the surface of the wall. o Types:  Recessed Outlet Box: For outlets installed in a wall without protruding.  Recessed Junction Box: Used for splicing connections while being flush with the wall or ceiling. **7. Metal and Plastic Boxes:** o Metal Boxes:  Material: Made from steel or aluminum. o Plastic Boxes:  Material: Made from PVC or other insulating plastics. **8. Old Work (Retrofit) Boxes:** o Purpose: Designed for installation in existing walls without needing to remove drywall. They have adjustable features to secure them in place. **Summary:** Electrical boxes play a critical role in safely housing and protecting electrical components and connections. They come in various types and sizes to meet different needs, from containing outlets and switches to housing junctions and circuit breakers. Proper selection and installation of electrical boxes are essential for ensuring the safety and functionality of an electrical system. **What are the electrical conductors use in residential wiring?** Electrical conductors are materials that carry electric current from one point to another. In residential wiring, these conductors are used to distribute electricity throughout a home, powering various devices and appliances. The choice of conductor materials and types is crucial for ensuring safety, efficiency, and reliability in the electrical system. **Types of Electrical Conductors Used in Residential Wiring:** **1. Copper Conductors:** Copper is the most common material used for residential electricalwiring due to its excellent conductivity, flexibility, and resistance to corrosion.  Solid Copper Wire: Single, solid strand used for most residential wiring.  Stranded Copper Wire: Multiple small wires twisted together, offering greater flexibility for applications requiring bending and maneuverability. **2. Aluminum Conductors:** Aluminum is lighter and less expensive than copper but has higher resistance and is less flexible. It\'s typically used in larger gauge sizes for specific applications. **3. Thermoplastic Insulated Conductors:** Conductors covered with a thermoplastic material that provides insulation and protection. Commonly used in residential wiring. o Types:  NM-B (Non-Metallic Sheathed Cable): Also known as Romex, this type of cable is widely used for indoor wiring in residential settings.  THHN (Thermoplastic High Heat-resistant Nylon-coated): Insulated wire used in conduit systems. **4. Thermoset Insulated Conductors:** This insulation is more durable under high temperatures. o Types:  XHHW (Cross-Linked High Heat-resistant Wire): Used in both residential and commercial applications, providing excellent heat and moisture resistance. **5. Flexible Cords and Cables:** Cords and cables designed for flexibility and often used in appliances and power tools. o Types:  SJT (Service Junior Thermoplastic): A common type of flexible cord used for portable appliances and tools.  SOOW (Service Oil-resistant, Oil-resistant, Water-resistant): Used for applications requiring extra durability and flexibility, often in industrial settings. **Conductor Sizes and Ratings:** **1. Gauge Size:** The gauge size of a conductor determines its current-carrying capacity. Smaller gauge numbers represent larger wire sizes, which can handle higher currents. o Common Sizes: 12 AWG (American Wire Gauge): Commonly used for general-purpose circuits such as lighting and outlets. 14 AWG: Used for lower-current circuits, such as lighting in some cases (though not recommended for general outlets). 10 AWG: Used for circuits requiring higher currents, such as larger appliances. 6 AWG: Used for heavy-duty circuits, such as those for electric ranges or large air conditioning units. **2. Insulation Ratings:** Insulation ratings indicate the maximum temperature the wire can handle and whether it is suitable for specific environments. o Common Ratings:  THHN/THWN: Rated for temperatures up to 90°C (194°F) in dry locations and 75°C (167°F) in wet locations.  NM-B: Rated for 90°C (194°F) but should be used in temperatures not exceeding 60°C (140°F) in certain applications. **Summary:** In residential wiring, copper and aluminum are the primary conductors used, with copper being the most common due to its superior conductivity and flexibility. Conductors are insulated with materials like thermoplastic or thermoset to ensure safety and durability. The choice of conductor size and insulation type depend on the specific electrical requirements and application within the home. Proper selection and installation of electrical conductors are essential for ensuring a safe and reliable electrical system. **What is the difference between solid conductor and stranded conductor use in residential wiring?** In residential wiring, solid conductors and stranded conductors are two types of electrical wiring, each with its own characteristics and suitable applications. Here\'s a breakdown of the differences between them: **Key Differences:** **1. Flexibility:** o Solid Conductors: Rigid and less flexible, better for fixed installations. o Stranded Conductors: Highly flexible and easier to bend, ideal for applications requiring movement or frequent adjustment. **2. Conductivity:** o Solid Conductors: General offer slightly better conductivity due to having fewer junctions and connections. o Stranded Conductors: Slightly higher resistance due to the multiple strands, but this difference is usually minimal for residential applications. **3. Durability:** o Solid Conductors: More prone to breaking if bent repeatedly. o Stranded Conductors: More resistant to fatigue and breakage due to bending and movement. **4. Installation:** o Solid Conductors: Easier to work with in straight runs and fixed installations. o Stranded Conductors: Easier to work with in tight or complex installations where flexibility is needed. **Summary:** Solid conductors are best for stationary, fixed wiring installations due to their rigidity and slight edge in conductivity, while stranded conductors are preferred for applications requiring flexibility and movement. The choice between solid and stranded conductors will depend on the specific needs of the wiring installation and the requirements of the electrical system. **Working temperature of electrical conductors?** The working temperature of electrical conductors is crucial for ensuring safety and performance in electrical systems. It refers to the maximum temperature that a conductor can safely operate at without compromising its integrity, insulation, or performance. Different types of conductors and insulation materials have varying temperature ratings. Here's an overview: General Temperature Ratings for Electrical Conductors: **1. Thermoplastic Insulated Conductors:** o THHN (Thermoplastic High Heat-resistant Nylon-coated):  Working Temperature: 90°C (194°F) in dry locations.  Usage: Commonly used in conduit systems for general-purpose wiring. o NM-B (Non-Metallic Sheathed Cable), also known as Romex:  Working Temperature: 60°C (140°F) when used in damp or wet locations.  Usage: Common for residential wiring in walls and ceilings. **2. Thermoset Insulated Conductors:** o XHHW (Cross-Linked High Heat-resistant Wire):  Working Temperature: 90°C (194°F) in both wet and dry locations.  Usage: Used in both residential and commercial applications, offering high heat and moisture resistance. o THWN (Thermoplastic Heat and Water-resistant Nylon-coated):  Working Temperature: 75°C (167°F) in wet locations.  Usage: Similar to THHN but specifically rated for wet conditions. **3. High-Temperature Insulated Conductors:** o RT-125 (Rubber Thermoplastic, 125°C):  Working Temperature: Up to 125°C (257°F).  Usage: Used in applications requiring high heat resistance, often in industrial settings. o K-5000 (High-Temperature Thermoplastic): Working Temperature: Up to 150°C (302°F). Usage: Specialty applications where extreme temperatures are a factor. **4. Flexible Cords and Cables:** o SJT (Service Junior Thermoplastic): Working Temperature: 60°C (140°F).  Usage: Used for portable appliances and general-purpose extension cords. o SOOW (Service Oil-resistant, Water-resistant): Working Temperature: Up to 90°C (194°F). Usage: Heavy-duty, flexible cable used in industrial environments. **Summary:** The working temperature of electrical conductors varies based on the type of insulation and intended use. Common temperature ratings for residential wiring include 60°C to 90°C for standard conductors. For applications requiring higher temperature resistance, specialized conductors are available with ratings up to 150°C. Always consider the environmental conditions, installation practices, and load requirements to ensure safe and effective operation of electrical systems. **Applications of Electrical Conductors in Residential Wiring** **\*\*1. Power Distribution**  Main Service Entrance: Large conductors (e.g., 4 AWG to 500 kcmil copper or aluminum) are used to connect the home\'s electrical service entrance to the utility\'s power supply.  Sub-Panels: Conductors of varying sizes (e.g., 10 AWG to 2 AWG) are used to feed sub- panels from the main service panel. **\*\*2. Branch Circuits**  Lighting Circuits: Typically use 14 AWG or 12 AWG copper conductors. These circuits power light fixtures and are often protected by 15 A or 20 A circuit breakers.  General Purpose Outlets: 12 AWG copper conductors are commonly used for general outlets and are protected by 20 A breakers.  Dedicated Circuits: For appliances like refrigerators, microwaves, and washing machines, 10 AWG to 12 AWG copper conductors are used. These circuits are usually protected by 20 A or 30 A breakers. **\*\*3. Specialty Circuits**  Kitchen Appliances: For high-power appliances like ovens and dishwashers, 8 AWG to 10 AWG copper conductors are used, often protected by 30 A breakers.  HVAC Systems: Conductors sized 6 AWG to 10 AWG copper or aluminum are used to connect heating, ventilation, and air conditioning systems.  Electrical Vehicle Chargers: Dedicated circuits with conductors ranging from 6 AWG to 4 AWG copper or aluminum are used, protected by appropriate breakers depending on the charger's specifications. **\*\*4. Outdoors and Exterior Wiring**  Outdoor Lighting: Conductors with weather-resistant insulation, such as THWN or UF-B (Underground Feeder), are used for exterior lighting and are typically sized 12 AWG or larger.  GFCI Outlets: For outdoor outlets, 12 AWG copper conductors are used, protected by Ground Fault Circuit Interrupter (GFCI) breakers to ensure safety in wet conditions. **\*\*5. Low-Voltage Wiring**  Doorbells and Intercom Systems: Low-voltage conductors (e.g., 18 AWG) are used for doorbells, intercoms, and other low-power systems.  Home Automation: Low-voltage wiring (e.g., 16 AWG to 22 AWG) is used for home automation systems, including lighting controls and security systems. **\*\*6. Grounding**  Grounding Conductors: Typically use 8 AWG or larger copper or aluminum conductors to connect the grounding system to the main service panel and grounding rods. **\*\*7. Additional Considerations**  Insulation Types: Conductor insulation types such as THHN (Thermoplastic High Heat- resistant Nylon-coated), THWN (Thermoplastic Heat and Water-resistant Nylon-coated), and UF (Underground Feeder) are chosen based on the installation environment and requirements.  Code Compliance: Ensure all wiring complies with the National Electrical Code (NEC) and local regulations to ensure safety and performance. This includes proper conductor sizing, insulation, and protection. **Summary** In residential wiring, conductors are used to distribute power, provide connections for various appliances and systems, and ensure safety through grounding and circuit protection. The choice of conductor size, type, and insulation depends on the application, current-carrying requirements, and environmental conditions. Proper installation and adherence to electrical codes are crucial for the safety and efficiency of the home\'s electrical system. **Types of Electrical Conduits** 1\. Electrical Metallic Tubing (EMT): Thin-walled, rigid metal conduit made from galvanized steel or aluminum. 2\. Rigid Metal Conduit (RMC): Heavy-duty, thick-walled steel or aluminum conduit. 3\. Intermediate Metal Conduit (IMC): Similar to RMC but with a thinner wall, making it lighter. 4\. PVC Conduit: Made from polyvinyl chloride, this conduit is flexible and lightweight. 5\. Flexible Metal Conduit (FMC): Also known as \"flex,\" it is a spiral-wound metal conduit that can bend easily. 6\. Liquidtight Flexible Nonmetallic Conduit (LFNC): A flexible, nonmetallic conduit with a smooth, water-resistant outer jacket. **WIRING METHODS** **Summary** Choosing the right **wiring method** depends on the specific requirements of the installation, including environmental conditions, safety considerations, and code compliance. Each method has its own advantages and is suitable for different applications:  Conduit Wiring: Offers protection and is used where physical damage is a concern.  Cable Wiring: Simplifies installation in residential settings and is suitable for dry or moderately wet locations.  Surface Raceway Systems: Useful for exposed wiring and retrofit applications.  Knob-and-Tube Wiring: An outdated method that is generally replaced by modern systems.  Structured Cabling: Provides standardized solutions for data and telecommunications.  Code Compliance: Ensures safety and reliability in all installations. **Summary** **Electrical raceways** are essential for organizing, protecting, and routing electrical wiring. The choice of raceway type depends on factors such as the environment, the type of installation, and the specific needs of the wiring system. Each type of raceway offers different advantages and is suitable for various applications:  Conduit Raceways: Provide physical protection and are suitable for various environments.  Surface Raceway Systems: Used for exposed wiring and are easy to install.  Cable Trays: Ideal for managing large cable runs and provide good ventilation.  Ducts and Trunking Systems: Enclosed systems for managing and protecting multiple cables.  Busways: Used for distributing electrical power with flexibility and ease of modification. **Summary** The selection of **electrical tubing (conduits)** depends on the environment, the level of protection required, and specific code compliance. Here's a summary of the main types:  EMT: For indoor, exposed wiring where flexibility and cost are concerns.  RMC: For high-durability needs, including outdoor and underground wiring.  IMC: Lighter than RMC but still provides strong protection.  PVC: A cost-effective, corrosion-resistant option for underground and wet locations.  FMC and LFMC: For applications requiring flexibility, especially around corners or in areas subject to vibration.  LFNC: For moisture-prone environments requiring nonmetallic flexible conduit. **SERVICE ENTRANCE** Service Entrance refers to the point at which electrical power is brought into a building or facility from the utility power distribution system. It encompasses all the components and equipment required to safely and efficiently deliver electricity to the building electrical system. **Here's a comprehensive overview of what service entrance involves:** **Components of a Service Entrance** **1. Service Drop or Service Lateral** o Service Drop: For overhead power lines, the service drop is the portion of the power lines that run from the utility pole to the building. o Service Lateral: For underground power lines, the service lateral is the section of the cable that runs from the utility's distribution system to the building. **2. Service Head**: The service head is the weatherproofed enclosure where the overhead service drop connects to the building. It includes a fitting for connecting the power lines and provides a point of entry for the wires into the building. **3. Meter**: The electric meter measures the amount of electrical energy consumed by the building. o Types:  Analog Meters: Mechanical meters with dials that record usage.  Digital Meters: Electronic meters that display usage digitally.  Smart Meters: Advanced digital meters with communication capabilities to transmit usage data remotely. **4. Main Service Panel (Electrical Panel)**: The main service panel houses the circuit breakers or fuses that control the electrical distribution within the building. o Components:  Main Breaker: A switch that can shut off the entire electrical system.  Circuit Breakers or Fuses: Protect individual circuits from overloads and short circuits. **5. Service Disconnect**: A switch or breaker that allows the electrical service to be disconnected from the building's wiring system. **6. Grounding System**: A system designed to safely divert electrical faults or surges to the ground, preventing electrical shocks and protecting equipment. **o Components:**  Ground Rods or Plates: Metal rods or plates driven into the ground to provide a grounding path.  Grounding Conductors: Wires that connect the grounding system to the electrical panel and other equipment. **7. Service Entrance Cable**: The cable that runs from the service drop or lateral into the building, connecting the utility's power supply to the main service panel. o Types:  Service Entrance Cable (SE Cable): Used for both overhead and underground service entrances.  Underground Service Entrance Cable (USE Cable): Specifically designed for underground installations. **Installation and Safety Considerations** **1. Code Compliance:** o National Electrical Code (NEC): Ensures that service entrances meet safety and performance standards. o Local Codes: May have additional requirements based on regional regulations. **2. Proper Grounding:** o Grounding Electrode System: Must be properly installed to ensure effective grounding. o Bonding: Ensures that all metallic parts of the electrical system are properly connected to the grounding system. **3. Service Size:** o Capacity: The service entrance must be sized appropriately to handle the electrical load of the building. This includes calculating the total demand and ensuring that the service equipment can accommodate it. **4. Accessibility:** o Location: The service entrance should be easily accessible for maintenance and emergency shutdowns. o Protection: Components should be protected from physical damage and environmental conditions. **5. Inspection:** o Routine Inspections: Regular inspections by a licensed electrician ensure that the service entrance and related components are functioning correctly and safely. **Summary**  **Service Drop Wire** is the segment of the electrical system that runs from the utility company's distribution lines to the building's service head in overhead installations.  **Service Entrance Wire** is the segment that runs from the service head (in overhead installations) or service lateral (in underground installations) into the building, connecting to the main service panel. **Summary** An **overhead service entrance** is a system used to bring electrical power from the utility&\#39;s distribution system into a building through overhead power lines. It includes components such as the service drop, service head, service entrance cable, main service panel, service disconnect, and grounding system. Proper installation, maintenance, and adherence to safety codes are essential to ensure the reliability and safety of the electrical service entrance. **Summary** An **underground service entrance** involves bringing electrical power from the utility company distribution system to a building through underground cables. It includes components such as the service lateral, utility box or manhole, service entrance cable, main service panel, service disconnect, and grounding system. This method provides a clean appearance and can be less susceptible to weather-related issues compared to overhead systems. Proper installation, adherence to codes, and regular maintenance are essential for ensuring the safety and reliability of the underground service entrance. **DEMANDS LOAD CALCULATION** In the Philippine Electrical Code (PEC), demand load calculations for residential buildings are essential to ensure that the electrical system is capable of handling the total load while maintaining safety and efficiency. The PEC outlines specific formulas and procedures for calculating demand loads for different areas and appliances in a residential setup. Here are the key formulas and steps based on the PEC for calculating residential demand loads: **1. General Lighting and General Use Receptacles** The demand load for lighting and general-use receptacles in a residence is calculated based on the total floor area of the house. The PEC uses a volt-ampere (VA) value per square meter to estimate the load.  Formula: Total VA=Total Floor Area (m²) × 24 VA/m² **2. Small Appliance Loads** According to the PEC, residential kitchens, dining rooms, and laundry areas must have separate small appliance circuits, typically rated at 20 A each Formula: Total VA for small appliances=Number of Circuits×1500 VA. **3. Laundry Circuit Load** Laundry areas require at least one dedicated circuit rated at 1500 VA. **4. Fixed Appliances (Air Conditioners, Water Heaters, etc.)** For each fixed appliance, calculate the load based on the nameplate rating in VA or kW.  Formula for Appliances: VA Load for Each Appliance=Rated Power (W or VA) **5. Range and Cooking Appliances**  Formula for Range: Use the nameplate rating of the range in VA (or watts) and apply the demand factor listed in the PEC based on the rating and the number of units. **6. Air Conditioning Load** Air conditioning units require a separate calculation based on their nameplate rating. For each air conditioning unit:  Formula: AC Load (VA)=Nameplate Rating (VA or W) No demand factor is applied unless otherwise specified by the PEC. **7. Total Load Calculation** Once individual loads have been calculated, sum up all the loads: **Voltage drop** is the reduction in voltage in a circuit between the source (such as the main panel) and the load (such as outlets, lights, or appliances). Excessive voltage drop can lead to poor performance of electrical devices and inefficient energy use. The Philippine Electrical Code (PEC) recommends that voltage drop in branch circuits not exceed 3%, and the total voltage drop (including feeders and branch circuits) should not exceed 5%. 1\. Basic Formula for Voltage Drop Calculation For single-phase circuits (common in residential setups), the voltage drop is calculated using the following formula: Vd=2 × I × L × R/1000V​ Where:  Vd​ = Voltage drop (in volts)  I = Current (in amperes)  L = Length of the conductor (in meters)  R = Resistance of the conductor (in ohms per 1000 meters)  The factor 2 accounts for both the outgoing and return conductors (since the current flows through both). **WIRE TYPE** **Temperature rating not to exceed:** ** THHN/THWN: 90°C dry and damp, 600V** ** THHN/THWN: 75°C wet or in oil, 600V** ** THWN-2: 90°C dry, wet or in oil, 600V**