Arc Fault Protection PDF

YOOOO!!!  ARC FAULT PROTECTION Electrical Fires in the U.S. : Each year, 42,900 fires result from electrical equipment, causing 370 deaths and over $615 million in property damage. Fires often stem from: Fixed wiring: 15,200 fires Faulty cords/plugs: 7,800 fi...

YOOOO!!!  ARC FAULT PROTECTION Electrical Fires in the U.S. : Each year, 42,900 fires result from electrical equipment, causing 370 deaths and over $615 million in property damage. Fires often stem from: Fixed wiring: 15,200 fires Faulty cords/plugs: 7,800 fires Lamp/light fixtures: 8,400 fires Residential Fires: According to a 1987 study by the U.S. Consumer Product Safety Commission, electrical fires occur throughout homes, especially in bedrooms, living rooms, and kitchens. Arcing and sparking in building wiring cause over 40,000 home fires annually, claiming more than 350 lives and injuring around 1,400 people.  ARC FAULT PROTECTION Arc Faults It is an unintentional electrical discharge that can ignite nearby combustibles. These faults are caused by the breakdown of insulation around wiring, which can occur due to: Aging, dust, shifting foundations, or rodent damage Sharp objects (like nails) piercing new wiring  ARC FAULT PROTECTION Types of Arc Faults: 1.Parallel Arcing Fault: Occurs when wires of opposite polarity come into direct contact 2.Ground Arcing Fault: Arcs between a conductor and ground 3.Series Arcing Fault: Arcing across a break in a single conductor  ARC FAULT PROTECTION AFCI (Arc Fault Circuit Interrupter) A safety device designed to detect arc faults and prevent fires. AFCIs monitor voltage and current, detecting abnormal patterns associated with arcing and cutting off the circuit before a fire can start. AFCI Application: AFCIs protect 15 A and 20 A branch circuits in residential settings. They are available as circuit breakers that combine standard thermal-magnetic protection with arc detection.  ARC FAULT PROTECTION Circuit Breaker Type A branch/feeder AFCI breaker with protection provided to branch-circuit wiring in the form of a circuit breaker.  ARC FAULT PROTECTION Convenience Outlet Type An outlet AFCI for protecting connected cord sets and power- supply cords in the form of an outlet receptacle.  ARC FAULT PROTECTION Portable Type A portable AFCI for protecting connected cord sets and power- supply cords that can be moved from outlet to outlet.  ARC FAULT PROTECTION Cord-Mounted type A cord-mounted AFCI for protecting the power -supply cord connected to it (in the form of an attachment plug on a power- supply cord).  NUISANCE TRIPPING Sensitivity of GFCIs and AFCIs: Ground Fault Circuit Interrupters (GFCIs) and Arc Fault Circuit Interrupters (AFCIs) are highly sensitive devices, designed to protect against electrical hazards. Nuisance Tripping: Due to this sensitivity, these devices can trip frequently, a phenomenon known as nuisance tripping. While designed to protect, the frequent interruptions can be inconvenient for users. Causes of Nuisance Tripping: Appliances beginning to fail: Devices with deteriorating performance can cause the circuits to trip unexpectedly. External factors: Lightning strikes can also trigger nuisance tripping. Impact on Essential Appliances: It is not recommended to connect essential equipment (such as refrigerators and freezers) to outlets with GFCI or AFCI protection, as nuisance tripping could lead to power loss, potentially causing food spoilage or damage to perishable goods Extremely Low-Frequency Electromagnetic Fields (EMF) Extremely low-frequency electromagnetic fields (EMF) are invisible, silent magnetic fields produced whenever electricity flows through a wire, appliance, or equipment. EMF is measured in milligauss (mG), while the scientific community commonly uses microtesla (μT).The relationship between these two units is: 1 μT = 10 mG ELF (Extremely Low-Frequency) meter  EMF HEALTH STUDIES Numerous studies have explored the connection between EMF exposure and human health, particularly concerning cancer risks. Child Leukemia:A notable study in Denver and another in Sweden found that children living near power lines exhibited higher leukemia rates compared to those further away. Epidemiological Findings: Most studies indicate little evidence linking EMF exposure from power lines or electrical occupations (like welders and electricians) to increased cancer rates. Cancer Classification: The International Agency for Research on Cancer has classified EMF as “possibly carcinogenic” to humans, highlighting the need for further research. Health Associations:While studies are not definitive, some suggest a potential connection between EMF exposure and health issues, such as sleep rhythm  EMF MITIGATION 1.Relocation: METHODS Move the source of EMF or the affected equipment to a distance from the high EMF area when feasible. 2.Shielding: Passive Shielding: Use conductive materials (e.g., metal screens) to block EMF. The shield must be grounded for effectiveness. Active Shielding: Employ systems that detect magnetic fields and generate currents to cancel them out, thereby reducing EMF levels. 3.Correct Wiring Errors: Address net-current wiring issues that lead to high EMF levels, as these cannot be effectively shielded using traditional materials. Ground Fault Protection of Equipment (GFP) Ground Fault Protection (GFP) is essential for detecting and interrupting low-level ground faults in electrical systems, particularly in modern commercial buildings with higher voltage electrical services (480/277 V). These systems can experience arcing to ground due to reduced spacing between energized parts and grounded components, leading to severe hazards like equipment damage and fires. How GFP Works: Monitoring Current: GFP operates similarly to Ground Fault Circuit Interrupters (GFCIs) by continuously monitoring the current flowing through the conductors. Current Transformer (CT): A current transformer encircles the conductors and generates a low-current output signal if there is an imbalance in the current flow (i.e., current leaving the load does not return through the same path). Ground Fault Relay: This signal is sent to a ground fault relay that has adjustable sensitivity and time delay settings. If the imbalance persists beyond the set time delay, the relay activates and opens the circuit or switch to interrupt power. Pickup Settings: Typical ground fault relays can be set to trigger at currents ranging from 100 to 1200 A. Time Delays: Time delays can be adjusted from instantaneous tripping to 0.5 seconds. Application: GFP is typically required for low-voltage systems with solidly grounded neutrals rated 1000 A or more when the phase-to -ground voltage exceeds 150 V. It is generally applied at the main service disconnect in buildings. Thank you BUILDING ELECTRICAL MATERIALS AND EQUIPMENT AYOSSS!!!! 01 CONDUCTO R INSULATI ON Conductor Insulation  Provides electrical isolation, physical protection, prevents power loss, and prevents short circuits and ground faults.  Modern wires use plastic insulation, which is durable. Older wires used cloth or rubber, but these materials deteriorate over time.  CONDUCTOR INSULATION INDOOR WIRING OUTDOOR WIRING Less exposure to Exposed to water and elements. UV light, requiring insulation that can withstand these conditions. Conductor Insulation  Needs insulation capable of withstanding damp, corrosive soil environments. Conductor Insulation  Special applications use an additional jacket over the insulation to provide chemical, physical, or thermal protection. Conductor Insulation  Most building conductors can operate up to 600 V. Conductors above 600 V require better insulation and shielding to prevent electromagnetic interference, making them more expensive. Conductor Insulation  Insulation varies in heat tolerance, with common ratings being 140°F (60°C), 167°F (75°C), and 194°F (90° C). Conductor Insulation  Dry locations: Enclosed, indoor areas.  Damp locations: Protected outdoor areas like covered decks.  Wet locations: Exposed to weather or severe moisture (e.g., buried or concrete-encased conductors). Conductor Insulation  Different letter codes indicate the insulation material and the safe environment for its use. COMMON CONDUCTOR THHN or THWN-2 conductor RHH or RHW-2 conductor 02 CABLE CABLES  A cable contains more than one conductor bundled together in a factory assembly of wires. An outer sheathing encases and protects the conductors, simplifying installation of multiple wiring  UNDERGROUND FEEDER CABLE UF (Underground Feeder) cables are flame retardant, moisture, fungus, and corrosion resistant. They come in sizes from No. 14 AWG copper to No. 4/0 AWG aluminum. Unlike NM or NMC cables, UF cables have sheathing that fully encases the conductors and are used for direct burial as feeders or branch conductors. MC cables can be used in places where AC cables are not permitted. FLAT CONDUCTOR CABLE Flat Conductor Cable (FCC) is a thin wiring system with three or more conductors, designed to be placed between a smooth subfloor and carpet squares. It supports general-purpose and appliance circuits up to 20 A, as well as individual circuits up to 30 A, with system voltages up to 300 V between ungrounded conductors. SERVICE ENTRANCE CABLE SE (Service entrance) cable is for above- ground use, while USE (Underground service entrance) cable is for underground applications. USE cables without flame retardant cannot be used indoors, but dual- marked USE/RHW and USE-2/RHW-2 cables are suitable for both outdoor and indoor conduit installations. ARMORED CABLE Armored cable (AC or ACT), also known as BX cable, consists of 2 to 4 copper conductors (14 AWG to 1 AWG) enclosed in a flexible metallic spiral. ACT cable has thermoplastic insulation, while AC uses rubber insulation. AC includes a 16 AWG bonding strip, which contacts the metal armor, allowing it to act as an equipment ground. METAL-CLAD CABLE Metal-clad (MC) cable, unlike armored cable, supports a wider range of conductor sizes and materials. Its armor can't serve as an equipment ground but complements an internal grounding conductor. MC cable is usable in more locations than AC cable. THERMOSTAT CABLE Thermostat cable is used for low-voltage applications under 30 V, such as doorbells, chimes, and thermostats. It typically contains No. 16 or No. 18 AWG conductors bundled in thin plastic sheathing. 03 CORDS  CORDS Cords are made of stranded conductors within flexible insulated sheathing, designed for flexibility and bending. They are typically manufactured with lighter gauge conductors (e.g., No. 18 or No. 16 AWG) and are used for power tools, large equipment, and detachable power cords. Extension cords, made with stranded wires, offer flexibility, allowing them to bend and twist without stressing the conductors. 04 CONCEALE D KNOB- AND-TUBE CONCEALED KNOB-AND- TUBE an old wiring technique using insulated conductors supported by glass or porcelain knobs and tubes. The ungrounded (hot) and neutral wires are run on opposite sides of joists or studs, with ceramic knobs and tubes preventing abrasion. This wiring is concealed behind walls or ceilings, but heat buildup can occur if encased in insulation, making it unsafe in such conditions. CONCEALED KNOB-AND- TUBE was widely used until the 1930s, though still permitted in original installations. It was replaced by armored cable due to safety concerns. Insurance companies often require inspections for homes with K&T wiring. Although largely outdated, K&T wiring is still used for temporary lighting and decorative purposes in certain settings but is prohibited in hazardous locations.  05 Conductor Power Loss Heat generated by current flow through a conductor results in a loss of power. This lost power is referred to as power loss or line loss. Power loss (Ploss) in a conductor can be computed with amperage (I) or voltage (V) and resistance (R) by the following formula:  05 Conductor Power Loss Power loss is converted directly to heat. Power loss is equivalent to heat produced. The relationship between power and heat is 1 W 3.413 Btu/hr. Heat produced (q) for a known power loss (Ploss) can be computed by the following formula: MOTOR CONTROLLERS A motor controller is a switching device designed to start, stop, and protect the motor. A controller might also be called on to provide functions such as reversing, jogging (repeated starting and stopping), plugging (rapid stopping by momentarily reversing the polarity of the motor), operating at several speeds, or at reduced levels of current and motor torque. MOTOR CONTROLLERS An Motor Control Centers (MCC) is a centrally located, sheet metal, cabinet-like enclosure that houses starters and controls that control and protect several mo tors. The front panel of an MCC contains operator controls and gauges. The interior of the MCC contains plug- in units such as starters, controls, and specialized units. MOTOR CONTROLLERS A variable-frequency drive (VFD) is a solid-state electronic power conversion device used for controlling the rota tional speed of an AC electric motor by controlling the frequency of the electrical power supplied to the motor. The motor used in a VFD system is typically a three- phase induc tion motor, but some types of single-phase motors can be used. 18.8 OCCUPANT PROTECTION NEED FOR OCCUPANT PROTECTION In the United States, hundreds of people are accidentally electrocuted each year. Electrocution occurs when a small amount of electrical current flows through the heart for I to 3 s. The amount of 0.006 to 0.2 A (6 to 200 milliamps, or mA) of current flowing through the heart disrupts the normal coordination of heart muscles. These muscles lose their vital rhythm and begin to fibrillate. Death soon follows. To provide an example of how small an amount of current it takes to kill: a 15 W nightlight on a 120 V circuit draws about 13 mA, enough amperage to cause electrocution. 18.8 OCCUPANT PROTECTION TAMPER-RESISTANT RECEPTACLES According to U.S. Consumer Product Safety Commission data, approximately 2400 children suffer electrical injuries each year from incidents involving electrical outlets or receptacles, Tamper resistant receptacles have built-in shutter systems that prevent foreign objects from touching electrically live components when these are inserted into the slots. The shutters protect against electrical burns without impairing normal plug insertion, removal, or function. GROUND FAULT INTERRUPTION Arentground fault occurs when electrical cur- leaks or escapes to ground. When a hot bare conductor inside an appliance inadvertently touches the metal housing, the housing may become charged with electricity. A GROUND FAULT IS THE UNINTENTIONAL FLOW OF ELECTRICAL CURRENT BE- TWEEN A ground fault circuit interrupter (GFCI) is an A POWER SOURCE, SUCH AS AN electrical device that detects an extremely low leak UNGROUNDED (HOT) WIRE, AND A (6 mA) of electrical current (called ground faults) GROUNDED SURFACE. and acts quickly to shut off power.  THREE TYPES OF GFCIS ARE COMMONLY AVAILABLE FOR USE IN A BUILDING RECEPTACLE OUTLET TYPE This type is generally used in place of standard duplex convenience outlets that are commonly found throughout the house. CIRCUIT BREAKER TYPE A GFCI circuit breaker can be installed in the panelboard in buildings equipped with circuit breakers.  PORTABLE TYPE Where permanent GFCIs are not possible or practical, portable GFCIs may be used. One type contains the GFCI circuitry in a plastic enclosure with plug blades in the back and convenience outlet slots in the front. It can be plugged into a convenience outlet so an electrical appliance plugged into the GFCI is protected. Another type of portable GFCI is one that is part of an extension cord, such as those required on new- model hair dryers.  PORTABLE TYPE One- and two-pole GFCI circuit breakers are available. One-pole GFCI breakers can be installed on the 120 V portion of a 120/240 V AC, 10-3W system that is typically found in residential and small commercial installations. Two-pole GFCI breakers are typically used in commercial and industrial appli- cations. They can be installed on a 120/240 V AC, 30-4W sys- tem, the 120/240 V portion of a 120/240 V AC, 30-4W system. and two ungrounded phases and the grounded phase of a 120/208 V AC, 30-4W system. THANK YOU!  TOPICS Building Transformers Overcurrent Protection: Fuses and Circuit Breakers Circuit Breakers Fuses OCP Device Ratings  BUILDING TRANSFORMERS SERVICE ENTRANCE AND MAIN DISTRIBUTION EQUIPMENT Service entrance and distribution panels serving a multifamily dwelling consists of several feeders extending from the main distribution panels to panelboards located at each apartment unit. A house panel serves outlets in common spaces (e.g., halls, laundry room, mechanical room, and so on). A life safety panelboard serves emergency lighting and smoke detectors. Circuits extend from the panelboards to the different outlets.  Transformers are used in transmitting and distributing power from the power plant to a substation. The operation of a large commercial installation depends on power distribution that, in turn, depends on transformers used to change voltage, current, and phase of electrical power nearby and within a building. Building transformers are rated in kVA. Typical sizes used in buildings include 3, 6, 9, 15, 25, 30, 37.5, 45, 50, 75, 112.5, 150, 225, 300, 500, 750, 1000, 1500 kVA, and larger. COMMON TYPES OF TRANSFORMER Step-down transformer has a secondary voltage that is less than its primary voltage. Step-up transformer is one with a secondary voltage that is greater than its primary voltage. Small transformers are typically air cooled by ventilation. Larger transformers are liquid cooled. Ventilated dry-type transformer has its core and coils in a gaseous or dry compound. Dry-type distribution transformers are usually found inside larger commercial/industrial facilities and are generally owned by the facility. Liquid-immersion transformer has its core and coils immersed in an insulating liquid.  SINGLE-PHASE TRANSFORMERS A single-phase transformer has a single primary winding and a single secondary winding. The 7200/240/120 V AC, single- phase, while the three-wire transformer is used in most residential and small commercial applications where 120 V and 240 V are required. In this transformer, 7200 V, two-wire power is transformed and stepped down to a 120/240 V AC, three-wire system. THREE-PHASE TRANSFORMERS Delta-connected transformers have a series of windings connected head to toe, with no single point common to all phases. They have a single voltage level available, and other voltages can only be obtained using step-up or step- down transformers. Wye-connected transformers have three independent transformer windings connected at a common point, called a neutral or star point. Delta Wye Transformer - is an electrical device that converts three-phase electric power without a neutral wire into three-phase power with a neutral wire.  OVERCURRENT PROTECTION: Fuses and Circuit Breakers  OVERCURRENT PROTECTION: Fuses and Circuit Breakers Overcurrent protection (OCP) devices protect building services or circuits from excessive current flows, preventing overheating. Fuses and circuit breakers are automatic OCP devices that open a circuit if current exceeds the device rating. OCP devices respond to short-circuit or ground-fault current values and overload conditions.  CIRCUIT BREAKERS  CIRCUIT BREAKERS A circuit breaker is an overcurrent protection device that serves two purposes: It acts as a switch that can be opened and closed manually, and most importantly, it automatically “trips off,” which opens the circuit when current flowing through it exceeds the circuit rating. This action instantaneously interrupts current flow. Once it trips, it can be reset (closed like a switch) and will continue to allow electricity flow as long as the current flowing through it does not exceed the circuit rating. The most popular circuit breaker is the thermal-magnetic type. It consists of a bimetallic strip that bends when it is heated by power loss created when current flows through it. When current flow is excessive, the circuit breaker heats up, bends, and trips a release that opens contacts and interrupts current flow. A magnetic device also can trip the release instantly if a short circuit develops. Circuit breakers protect the ungrounded (hot) conductors in a circuit. They are identified as: SINGLE POLE (SP) if protecting a single ungrounded conductor. TWO POLE (2P) when protecting two ungrounded conductors such as on a 240 V circuit. THREE POLE (3P) when protecting three ungrounded conductors on a three-phase circuit. FUSES  FUSE A fuse is an overcurrent protection device that consists of a strip of metal with a low melting temperature. Under normal operation, electricity flows through the metal strip. However, when its current rating is exceeded, the metal strip heats up and melts and the circuit is opened, thereby interrupting current flow. In this case, it is said that the fuse has “blown.” A new fuse of the same rating must replace a blown fuse, which is discarded. Most fuses are rated for 250 V or 600 V although 125 V and 300 V are available. STANDARD CURRENT RATINGS FOR FUSES BASIC TYPES OF FUSES TIME PLUG CARTRIDGE DELAY Screw into sockets Are cylindrical, Can handle an overload much like a lamp. available in ferrule- for fraction of a second contact and knife-blade without blowing. They types, rated up to 60 A. are desirable on circuitsserving electric motors. OCP DEVICE RATINGS  OCP DEVICE RATINGS OVERCURRENT RATING INTERRUPTING RATING  OVERCURRENT RATING The overcurrent rating of an OCP device is the highest amperage it can carry continuously without exceeding a specific temperature limit (e.g., without overheating). If the current (amperage) flowing through the protection device exceeds the device setting for a significant period, the OCP device will open. The overcurrent rating of an OCP is listed in amperes, such as 15 A, 20 A, or 30 A. The amperage carried by the electrical circuit or system protected by an OCP device must not exceed the maximum current rating of the circuit breaker.  INTERRUPTING RATING OCP devices must have an interrupting rating sufficient for the maximum possible fault-current (short-circuit). If the OCP is not rated to interrupt at the available fault-current, it could explode while attempting to clear the fault and/or the downstream equipment could suffer serious damage, causing possible hazards to occupants and property. The amperes interruption current (AIC) rating for circuit breakers is 5000 A and 10 000 A for fuses. Circuit breakers and fuses typically have an AIC rating of 10 000 A. THANK YOU!!! BUILDING ELECTRICAL MATERIALS AND EQUIPMENT  18.1 POWER GENERATION AND TRANSMISSION Explains how electricity is generated, transmitted, and distributed in the United States and Canada. This chapter focuses on the fundamentals of how electrical energy is generated and safely distributed to consumers.  18.1 POWER GENERATION AND TRANSMISSION Electricity Generation: Power Grid: Voltage Transmission: Most electricity comes from large Utility companies and small producers Power is generated at low voltages (2.4 utility companies, but some small are connected through a power grid kV to 13.2 kV) but is "stepped up" for producers, like manufacturers and where they buy and sell electricity. efficient long-distance transmission at homeowners with solar or wind Larger, more economical stations run voltages of 115 kV to 765 kV. systems, contribute. Substations near populated areas "step continuously, while less-efficient Power stations, either fossil-fuel or down" the voltage to safer levels for stations are activated during peak distribution to homes and businesses. nuclear, generate electricity through demand. turbines, which convert mechanical energy into electrical energy using generators.  These carry power from the transformer to the service entrance building’s service disconnects, passing through conductors a metering device. TWO TYPES OF SERVICE ENTRANCE CONDUCTORS Overhead conductors: These run from a pole-mounted distribution transformer to the building, commonly referred to as the service drop. Underground conductors: These buried cables are called the service lateral. Service entrance conductors must be insulated except the neutral, which may be bare in overhead installations. Single phase service drops will have either 2 or 3 wires while three phase service drops will have either 3 or 4 wires. Typically, service entrance conductors are provided by the utility. Each utility has standards on wire size and minimum clearances.  The service entrance includes the components that connect the utility’s wiring (either the SERVICE ENTRANCE service lateral or service drop) to the service disconnect, excluding the utility’s metering equipment. SERVICE EQUIPMENT KEY POINTS Metering equipment : to measure power usage. Main disconnect or switch gear: to cut off power to the building when necessary. Overcurrent protection devices : (like circuit breakers or fuses) that protect the service entrance conductors by shutting off the circuit in case of electrical overload.  service entrance Electric Meter: Service Disconnect The meter measures and records the electrical energy is a required part of the service entrance consumed by a building. equipment that allows electrical service from For services rated up to about 400 A, a feed-through the utility company to be switched off so meter is used. This operates like a small electric motor, that power is disconnected to the building where the speed of a rotating disc is proportional to the installation. It is a set of fuses or a circuit power consumed. This rotation drives pointers on dials to breaker that protects the service entrance record usage in kilowatt-hours (kWh). conductors. Current Transformer (C/T) Metering: For services rated above 400 A, a current-transformer (C/T) is used to measure amperage in each ungrounded (hot) conductor. These C/T metering devices are housed in a C/T cabinet, which is part of the service entrance equipment.  switchboards is a large cabinet or assembly of metal cabinets in which is connected disconnecting switches, overcorrect protection devices (fuses or circuit breakers), other protective devices, and instruments designed to divide large amounts of electrical current into smaller amounts of current used by electrical equipment. Function of Switchboards: Switchboards contain devices that can manually and automatically disconnect a circuit from its power source, providing control over electrical distribution. Capacity and Specifications: They are the highest-capacity components in building distribution and protection devices, typically rated for current levels between 1200 to 6000 amperes (A) and voltages below 600 volts (V). Access: Access to the switchboard is generally available from both the front and rear of the cabinet, allowing for maintenance and operation.  panelboards Is one or more metal cabinets that serve as a single unit, including buses, automatic overcurrent protection devices (fuses or circuit breakers). It is equipped with or without switches for the control of light, heat, and power circuits. A panelboard may be referred to in the trade as a power panel, load center, distribution center, or main power panel. A load center is a panelboard containing a preassembled disconnect and the necessary circuit breakers. It is typically used in residential applications. Structure: A panelboard consists of a sheet metal box (the cabinet) and a cover that encloses the interior. This design limits access to the power distribution components for safety. The enclosed interior contains: Vertical buses: These are used for power distribution. Overcurrent protection devices: These include circuit breakers or fuses that protect and supply branch circuits to outlets. Termination buses: These provide neutral and grounding connections for the branch circuits.  MECHANICAL
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ELECTRICAL SYSTEMS TABLE OF CONTENTS 18.6 ENCLOSURE AND RACEWAYS BUSWAYS WIREWAYS 18.7 ELECTRICAL MOTORS MOTOR RATINGS TYPES OF MOTOR UNIVERSAL MOTOR SPLIT-PHASE MOTOR CAPACITOR MOTOR INDUCTION MOTOR THREE-PHASE MOTOR DUAL-VOLTAGE MOTOR  18.6 ENCLOSURE AND RACEWAYS BUSWAY
WIREWAYS BUSWAY A busway is of a standardized, factory-assembled enclosure consists of outer duct-like housing, bus bars, and insulators. Busway systems are typically used in service equipment or as feeders because these systems are designed to carry large amounts of current. Two general types of busway systems: 1. Feeder Busway 2. Plug-in Busway  FEEDER PLUG-IN BUSWAY BUSWAY A feeder busway is used A plug-in busway is used to to deliver large amounts provide power tap-offs at of power with low voltage multiple points. It is available drop. It is available in sizes in 100 A to 3000 A sizes. from 600 A to several Plug-in busways make power thousand amps. distribution flexible. Power is available anywhere along the busway without necessitating a main service interruption. Busways are only used in large commercial and industrial installations (e.g., manufacturing plants) where large loads are concentrated (about 600 A and higher), where a large number of taps are required, or where superior fire and mechanical injury protection is desirable. Busways can also be salvaged and moved more easily and cost-effectively than ordinary conductors. WIREWAYS Wire gutters or wireways are sheet metal or nonmetallic, flame -resistant plastic troughs that serve as a housing that encloses and protects conductors. Access to the enclosure interior is through a hinged door or removable cover. Wire gutters and wireways typically carry large conductors.  18.7 ELECTRIC MOTORS MOTOR RATINGS

TYPES OF MOTOR
UNIVERSAL MOTOR
SPLIT-PHASE MOTOR
CAPACITOR MOTOR
INDUCTION MOTOR
THREE-PHASE MOTOR
DUAL-VOLTAGE MOTOR ELECTRIC MOTORS An electric motor is a device that converts electrical energy into mechanical energy. It works based on the principle of electromagnetism, where a current-carrying conductor generates a magnetic field, which interacts with an external magnetic field to produce force, causing rotation or motion. Motors are designed to operate on voltages slightly less than the building system voltage, because voltage available at the motor outlet is less than the building system voltage because of a voltage drop on the branch circuit conductors. Motors designed to operate at slower speeds are larger, operate quieter, and last longer because they encounter less friction.  MOTOR RATINGS Electric motors are rated in horsepower (hp). One horsepower is equivalent to 33 000 foot-pounds (ft-lb) of work per minute (550 ft-lb/s). This is about 1 ⁄8 the power an adult can produce continuously. In theory, one horsepower is equivalent to 746 W. However, because of losses from heat and friction, an electric motor delivers less work than the theoretical equivalent; more power is consumed than is produced.  TYPES OF MOTORS UNIVERSAL TheMOTOR universal motor is a fractional horsepower (less than one horsepower) motor designed to operate on both AC and DC power. Its rate of rotation varies considerably with load. It operates at high speeds under light load and low speeds with heavy load. The universal motor can free idle at up to 20 000 rpm. Universal motors are used on appliances such as blenders and vacuum cleaners and power tools such as routers and electric drills.  SPLIT-PHASE MOTOR The split-phase motor operates on single-phase AC only. The motor windings are configured so that single- phase AC power is split into two phases that are 1 ⁄2 out of phase. This type of motor starts slowly with low torque, so it is not capable of starting heavy loads. The split-phase motor is available in sizes up to 1 ⁄3 horsepower.  CAPACITOR MOTOR This type of motor operates on single- phase AC only. Capacitor-start motors have a capacitor that stores and discharges energy to help start the motor rotor. Capacitor-run motors have one or more capacitors to help start and run the motor. The capacitor motor is more efficient and has a better starting torque than the split- phase motor.  INDUCTION MOTOR These motors use electromagnetic induction to cause the motor rotor to turn. Repulsion-start induction motors are capable of handling heavy starting loads.  THREE-PHASE MOTOR Large motors operate more efficiently on three-phase AC power. Electric motors rated up to 71 ⁄2 hp can operate on a single-phase AC system. However, a single-phase motor rated at 71 ⁄2 hp draws a large amount of instantaneous current at startup (up to 200 A on a 240 V single-phase circuit). As a result, conductor size is large and costly. Three-phase motors also vibrate less than single-phase motors, so they are lighter and less costly.  DUAL-VOLTAGE MOTOR Motors above 1 ⁄4 hp are designed to operate on one of two different line voltages such as 115 V or 230 V. Larger motors operate more efficiently on a higher line voltage because of lower I 2 R losses. So, if a higher line voltage is available, it is used. AWESOME WORDS  CHAPTER 18 Building Electrical Materials and Equipment Rabino, Shanley Joy S.  18.4 UTILIZATION EQUIPMENT AND DEVICES ❑ Outlets, Receptacles, and Plugs ❑ Switches 18.5 CONDUCTORS ❑ Wire ❑ Buses ❑ Conductor Material ENGINEERING UTILITIES 1 18.4 UTILIZATION EQUIPMENT AND DEVICES ✓ Electric motors, air conditioning, refrigeration and heating units, signs, Utilization equipment is a broad category industrial machinery, of electrical or electronic machine or cranes, hoists, elevators, instrument designed to perform a specific and escalators fit in the mechanical, chemical, heating, or lighting category of utilization function through the use of electrical equipment. energy. ENGINEERING UTILITIES 1 An appliance is an end-use piece of utilization equipment designed to perform a specific function such Freezers as cooking, cleaning, cooling, or Clothes Washers and Dryers heating. Electric Ranges Toasters Blenders Hair dryers Refrigerators ENGINEERING UTILITIES 1  Seven Main Categories of Appliances 3 Categories of Appliances 1. Fixed Appliances 2. Stationary Appliances 3. IT Appliances 1. FIXED APPLIANCES 4. Movable Appliances 2. STATIONARY APPLIANCES 5. Portable Appliances 3. PORTABLE APPLIANCES 6. Cables and Charges 7. Hand Held Appliances ENGINEERING UTILITIES 1  EXAMPLES: 3 Categories of Appliances 1. FIXED APPLIANCES – permanently attached installations such as built-in cook top or oven. 2. STATIONARY APPLIANCES – situated and Storage Heaters Hand dryers used at a specific location but can be moved to another outlet such as a refrigerator, clothes washer, or clothes dryer. 3. PORTABLE APPLIANCES – appliances that can be easily carried or moved such as a hair dryer or toaster. Built-in cook top and Oven ENGINEERING UTILITIES 1  EXAMPLES: 3 Categories of Appliances 1. FIXED APPLIANCES – permanently attached installations such as built-in cook top or oven. 2. STATIONARY APPLIANCES – situated and Clothes Washer used at a specific location but can be moved to another outlet such as a refrigerator, clothes washer, or clothes dryer. 3. PORTABLE APPLIANCES – appliances that can be easily carried or moved such as a hair Refrigerator dryer or toaster. Clothes Dryer ENGINEERING UTILITIES 1  EXAMPLES: 3 Categories of Appliances 1. FIXED APPLIANCES – permanently attached installations such as built-in cook top or oven. 2. STATIONARY APPLIANCES – situated and Hair Dryer Toaster used at a specific location but can be moved to another outlet such as a refrigerator, clothes washer, or clothes dryer. 3. PORTABLE APPLIANCES – appliances that can be easily carried or moved such as a hair Electric Desk Fans dryer or toaster. ENGINEERING UTILITIES 1 An electrical device is a component in an electrical system that is designed to carry but not use electricity. Switches Receptacles Relays ENGINEERING UTILITIES 1 ❑ OUTLETS, RECEPTACLES, AND PLUGS In an electrical system, A receptacle is a female A plug is a male An outlet is the connecting device with connecting device that has slotted contacts. It is two or more prongs that are location in a branch installed at an outlet or inserted into a receptacle to circuit where connect to an electrical electricity is used. on equipment, where it is circuit. A plug is typically intended to easily connected to a flexible cord establish an electrical that is attached to a connection with an portable appliance, light, or inserted plug. equipment. ENGINEERING UTILITIES 1  According to National Electrical Manufacturing Association (NEMA) standards, the different types of receptacles and plugs are identified by a specific designation. ENGINEERING UTILITIES 1  The screw terminals on a receptacle are color coded: Brass-colored screws – for connection to the undergrounded conductor. Silver-colored screw – for the grounded or neutral conductor. Green-colored screws – for the equipment grounding conductor. ✓ Receptacles marked “CO/ALR” can be connected to copper, aluminum or copper-clad aluminum conductors. ✓ Receptacles marked “CU/AL” were formerly allowed for use with copper or aluminum conductors, built can only be connected to copper conductors. ENGINEERING UTILITIES 1 ❑ SWITCHES A simple switch is a device placed between two or more electrical conductors in a circuit to safely and intentionally open or close the circuit or to redirect the path of current in a circuit. ✓ Switches are rated by purpose, voltage, and amperage, and are classified for AC or DC. Safety switches are used in building electrical systems. They are designed to reduce the possibility of contact with bare electrical conductors and have current interrupting capability. ENGINEERING UTILITIES 1 TYPES OF SWITCHES General duty wall- Weatherproof Keyed switch mounted switch switch Locked lighting Emergency safety Heavy-duty switch switch panel cut-off switch ENGINEERING UTILITIES 1 Two Categories of Safety Switches Heavy-duty safety switches General duty safety switches - designed for heavy industry, - intended for industrial, general commercial, and institutional commercial and residential applications where safety, loads where economy is performance, and continuity of important and requirements are service are required. These are less stringent. They are used on enclosed and may be fused or lighting, heating, appliance, and unfused. intermittent motor loads. Ratings up to 1200 A, 600 V are Ratings up to 600 V are available. available. ENGINEERING UTILITIES 1  Single-pole, single-throw (SPST) switch Switching Terminology - a simple on/off switch and it opens or closes a single undergrounded conductor POLE refers to the number of in a circuit. conductors the switch is - it is the most commonly used switch found opening and closing. in buildings. THROW refers to the number of operations a switch can Single-pole, double throw (SPDT) switch perform. - diverts current from one conductor path to another. ❑ Three-way switch (𝑆3 ) - special type of SPDT - allows the control of an installation from two locations. ENGINEERING UTILITIES 1  Double-pole, single-throw (DPST) switch Switching Terminology - opens or closes two conductors in a circuit. - it is equivalent to two SPST switches POLE refers to the number of controlled by a single mechanism. conductors the switch is - it can be used to switch off the ungrounded opening and closing. and grounded conductors in a single lighting circuit that is serving a paint spray THROW refers to the number of operations a switch can booth containing explosive vapors. perform. ✓ Double-pole, double-throw (DPDT) and three-pole, single-throw switches are also available. ENGINEERING UTILITIES 1 Switching Configurations SWITCHES provide control from one or more points in a circuit. Single-pole, single-throw (SPST) is used to provide control from one point by opening or closing the ungrounded conductor in the circuit. Three-way (S3) and four-way (S4) switches are used when multiple control points are needed. ENGINEERING UTILITIES 1 Common switching configuration One single-pole, single-throw Control from one point switch (S) is required. Two tree-way switches (𝑆3 ) are Control from two points required. Two tree-way switches (𝑆3 ) and a four-way switch (𝑆4 ) are required. Control from three points The four-way switch must be wired between the three-way switches. Two tree-way switches (𝑆3 ) and two or more four-way switch (𝑆4 ) are Control from four or more points required. The four-way switch must be wired between the three-way switches. ENGINEERING UTILITIES 1  Control from one point ENGINEERING UTILITIES 1  Control from two points ENGINEERING UTILITIES 1  Control from three points ENGINEERING UTILITIES 1  Control from four or more points ENGINEERING UTILITIES 1 Specialty Switches Automatic switches deactivate a circuit after a preset time period has lapsed. Dimmer switch (SD) is a device in the electrical circuit for varying power to a circuit. Time clocks can be used to control the time period that a piece of equipment or a lighting installation operates. Electronic timers allow greater flexibility as they can easily be set for 7-day cycles. Photocell controls sense light and open or close a circuit with the presence of light. Occupancy sensors control a lighting or equipment installation by sensing occupants in a space. Infrared sensors respond to the motion of an infrared heat source, such as a person or animal. Ultrasonic sensors emit a high-frequency sound that is in the range of 25 to 40 kilohertz and well above the capacity of normal human hearing. ENGINEERING UTILITIES 1 18.5 CONDUCTORS ENGINEERING UTILITIES 1 ❑ WIRE An electrical conductor is any material that conducts electrical current. ✓ Wire is a common conductor Most conductors used in building applications are classified according to a wire gauge standard and on the cross-sectional area of the wire in units called circular mils. 1 mil = 1/1000 inch 1 circular mil (cmil) = cross-sectional area of a 0.001 in diameter circle ENGINEERING UTILITIES 1 ELECTRICAL CONDUCTORS are either solid or stranded ❖ Solid Conductors – a single solid length of conductor called a wire. ❖ Stranded Conductors – consist of smaller wire strands. ENGINEERING UTILITIES 1 ❑ BUSES BUS - sometimes called a bus bar - is an electrical conductor (usually copper or aluminum) that serves as a common connection for two or more electrical circuits. - they are commonly found in panel boards, switchboards, and other power distribution equipment. ENGINEERING UTILITIES 1 ❑ CONDUCTOR MATERIAL Scientifically, silver is the best electrical conductor material (other than a superconductor material) because it has the least resistance of common materials. Traditionally, copper and aluminum conductors are used in building conductor (wiring) installations as a compromise between good conductivity and economy. ENGINEERING UTILITIES 1  Thank You !!! “God hangs the greatest weights upon the smallest wires.” -Francis Bacon ENGINEERING UTILITIES 1