2 PEC_Wiring and Protection.pdf

PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) CHAPTER 2 - WIRING AND PROTECTION USE AND IDENTIFICATION OF GROUNDED CONDUCTORS Means of Identifying Grounded Conductors...

PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) CHAPTER 2 - WIRING AND PROTECTION USE AND IDENTIFICATION OF GROUNDED CONDUCTORS Means of Identifying Grounded Conductors a) Sizes 14 mm2 or Smaller  Continuous white or gray outer finish.  Three continuous white stripes on other than green insulation along its entire length. b) Sizes Larger Than 14 mm2  Continuous white or gray outer finish.  Three continuous white stripes along its entire length other than green insulation.  At the time of installation, distinctive white or gray marking at its termination. c) Flexible Cords  Shall be identified by a white or gray outer finish. d) Grounded Conductors of Different Systems  Shall have the grounded conductors for different systems distinguishable, one having white outer finish and the other a gray outer finish, other than green. BRANCH CIRCUITS Rating a) In General - The rating for other than individual branch circuits shall be 15, 20, 30, 40, and 50A. b) Over 50 Amperes - Multi-outlet branch circuits greater than 50A shall be permitted to supply non- lighting outlet loads. Ground Fault Circuit Interrupter Protection a) Dwelling Units - All 125/250 volts, single phase, 15-20 amperes receptacles installed in the following locations shall be of GFCI protection: 1. Bathrooms 2. Garages, and also accessory buildings that have a floor located below grade level 3. Outdoors 4. Crawl spaces - at or below grade level 5. Unfinished basements (not habitable rooms such as storage areas, work areas) 6. Kitchen (receptacles on countertops) 7. Laundry circuits, and wet bar sinks (receptacles within 1800 mm from the edge of sink) 8. Boathouses b) Other Than Dwelling Units - All 125/250 volts, single phase, 15-20 amperes receptacles installed in the following locations shall be of GFCI protection: 1. Bathrooms 2. Commercial and institutional kitchens 3. Rooftops 4. Outdoor in public areas c) Boat Hoists - All 125/250 volts, 15-20 ampere receptacles shall be GFCI protection. Circuits Derived from an Autotransformer - Branch circuits shall not be derived from autotransformers unless the circuit being supplied has a grounded conductor connected to the supplying autotransformer supply. Arc-Fault Circuit Interrupter (AFCI) - A device intended to provide protection from the effects of arc faults by recognizing characteristics unique to arcing and by functioning to de-energize the circuit when an arc fault is detected. 11 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 16 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) Dwelling Unit Bedrooms - All 115V and/or 230V, single phase, 15 and 20A shall be protected by a listed AFCI, combination type installed to provide protection of the branch circuit. This requirement is effective since last January 1, 2014. BRANCH-CIRCUIT RATINGS Conductors - Minimum Ampacity and Size 1. In General - Branch-circuit conductors shall have an ampacity not less than the maximum load to be served. Branch circuit conductors which supplies continuous load and combination thereof shall have an ampacity not less than 125% of the continuous load. 2. Household Ranges and Cooking Appliances - Fore ranges of 8¾ kW or more rating, shall have a minimum-branch circuit rating of 40 amperes. Branch circuit conductors that supply other loads, other than cooking and heating appliances shall have a conductor not smaller than 2.0 mm2 (1.6 mm dia.) Branch Circuits requiring at least 20A Overcurrent Protection -1500VA 1. Small Appliance Branch Circuits 2. Laundry Branch Circuits 3. Bathroom Branch Circuits 4. Dwelling Unit (50 m2) not more than 3680VA Permissible Loads - A branch circuit supplying two or more outlets or receptacles shall supply only the loads specified. 1. 15-20 Ampere Branch Circuits  Lighting Units, Utilization Equipments fastened in place, or combination of both 2. 30 Ampere Branch Circuits  Fixed Lighting Units with Heavy-Lampholders other than Utilization Equipments 3. 40-50 Ampere Branch Circuits  Cooking Appliances that are fastened to place 4. Branch Circuits Larger than 50 Amperes  Shall only supply non-lighting outlet loads Receptacle Outlets a) General Provisions - In every kitchen, family room, dining room, living room, parlor, library, den, sunroom, bedroom, recreation room, or similar room or area of dwelling units, receptacle outlets shall be installed in accordance with the following provisions: 1. Spacing - Not more than 1800 mm (1.8m) horizontally from the other receptacle outlet. 2. Wall Space - Shall provide outlets for any space 600 mm or more than in width (including space measured around corners) and unbroken along the floor line by doorways, fireplaces, etc. 3. Floor Receptacles - Not counted as part of the required num. of receptacle unless 450mm away from the wall. b) Countertops - In kitchens and dining rooms of dwelling units, receptacle outlets shall be of the installed in accordance with the following: 1. Wall Counter Spaces - Counter spaces that are 300 mm or wider requires a receptacle be installed 600 mm measured horizontally from it. 2. Island or Peninsular Counter Spaces - At least one receptacle shall be installed at each island counter space with a long dimension of 600 mm or greater and a short dimension of 300 mm or greater. When a rangetop or sink is dividing the island at dimensions of less than 300 mm, outlets are not required. 3. Receptacle Outlet Location - Receptacle outlets shall be located above, but not more than 500 mm above, the countertop. 12 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 17 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) c) Bathrooms - Shall have at least one receptacle within 900 mm from the outside edge of each basin. d) Outdoor Outlets - For a one-family dwelling and each unit of dwelling units shall have at least one accessible outlet at grade level not more than 2000 mm in front and back of the dwelling unit. e) Laundry Areas - Shall have at least one receptacle installed for the laundry. f) Basement and Garages - Shall have at least one receptacle outlet be installed. g) Hallways - In dwelling units, 3000 mm (3m) or more in length shall require at least one receptacle outlet. h) Show Windows - At least one receptacle directly above for each 3600 mm linear width. i) Heating, Air-conditioning and Refrigeration Equipment Outlet - Special individual outlets shall be installed and be located on the same level 7600 mm within the equipment. Lighting Outlets Required 1. Habitable Rooms 2. Hallways, Stairways, Attached Garages, Detached Garages with Electric Power 3. Attached and Detached Garages 4. Interior Stairways (six risers or more) 5. Storage and Equipment Spaces 6. Guest Rooms or Guest Suites 13 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 18 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) FEEDERS Minimum Rating and Size a) In General - Feeders shall have an allowable ampacity not less than the noncontinuous load plus 125% of the continuous load. b) Ampacity Relative to Conductors - Feeders for systems with 600 volts, or less, shall have an ampacity not less than that of the service and carry the total load supplied with 55 amperes or less. Feeders with Common Neutral - Two or three sets of 3-wire feeders or two sets of 4-wire or 5-wire feeders can have common neutral. BRANCH CIRCUIT, FEEDER, AND SERVICE CALCULATIONS Calculations a) Voltages - Unless other voltages are specified, for purposes of calculating branch-circuit and feeder loads, nominal system voltages of 115, 115/230, 208Y/120, 230, 347, 400Y/230, 460Y/265, 460, 600Y/347, and 600V shall be used. b) Fractions of an Ampere - An ampere that is less than 0.5, shall be permitted to be dropped. c) Other Loads - All Occupancies 1. Heavy-Duty Lampholders - Outlets shall be calculated at minimum of 600VA. 2. Sign and Outline Lighting - Outlets shall be calculated at minimum of 1200VA. 3. Show Windows - Shall be calculated at 200VA per 300 mm show window. 4. Track Lighting - 150VA included for every 600 mm of track lighting. 5. Banks and Office Buildings - The receptacle loads shall be calculated at 28VA/m2 6. Receptacle Outlets  1 Yoke - Each single or multiple receptacle is 180VA  Multiple Receptacles (4 or more) - 90 VA per receptacle General Lighting Loads by Occupancy Unit Load Type of Occupancy (VA/m2) Storage Spaces 2 Warehouses (Storage) 2 Halls, Corridors, Closets, Stairways 4 Garages (Commercial Storage) 4 Armories and Auditoriums 8 Assembly Halls and Auditoriums 8 Churches 8 Lodge Rooms 12 Clubs and Restaurants 16 Court Rooms 16 Hospitals 16 Hotels and Motels, including apartment houses without provision for 16 cooking by tenants Barber shops and Beauty parlors 24 Dwelling Units 24 Schools 24 Stores 24 Banks 28 Office Buildings 28 14 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 19 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) Feeder and Service Load Calculation a) General Lighting- The demand factors shall apply to that portion of the total branch-circuit load calculated for general illumination. Shall not be used for determining the number of luminaires. Lighting Load Demand Factors Demand Type of Occupancy Portion of Lighting Load Factor  First 3000 VA 100 Dwelling Units  3001 VA - 120,000 VA 35  Remainder over 120,000 VA 25  First 50,000 VA or less 40 Hospitals  Remainder over 50,000 VA 20 Hotels and Motels, including apartment  First 20,000 VA or less 50 houses without  20,001 VA - 100,000 VA 40 provision for cooking  Remainder over 100,000 VA 30 by tenants  First 12,500 VA or less 100 Warehouses (storage)  Remainder over 12,500 VA 50 All Others  Total Volt-Ampere 100 b) Show Windows - A load of not less than 660VA/linear meter shall be included for a show window, measured horizontally along its base. c) Track Lighting - Shall include an additional load of 150VA included for every 600 mm of track lighting d) Electric Clothes Dryers - Dwelling Unit(s) - The load shall be either 5000 watts (VA) or the nameplate rating, whichever is larger, for each dryer served. Demand Factors for Household Electric Clothes Dryer Number of Dryers Demand Factor 1-4 100% 5 85% 6 75% 7 65% 8 60% 9 55% 10 50% 11 47% 12-22 % = 47% - (number of dryers - 11) 23 35% 24-42 % = 35 - [ 0.5 x (number of dryers - 23)] 43 and over 25% 15 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 20 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) e) Kitchen Equipment - It shall be permissible to calculate the load for commercial electric cooking equipment, dishwasher booster heaters, water heaters, and other kitchen equipment in accordance to the table. f) Electric Ranges and Other Cooking Appliances - The load for household electric ranges, wall- mounted ovens, counter-mounted cooking units, and other household cooking appliances individually rated in excess of 1¾ kW shall be permitted to be calculated in accordance to this table: 16 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 21 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) Optional Feeder and Service Load Calculations  Heating and Air-Conditioning Load a) 100% - Air-Conditioning and Cooling b) 100% - Heat Pump without any Supplementary Electric Heating c) 100% - Electrical Thermal Storage d) 100% - Heat Pump Compressor and 65% - Supplemental Electric Heating e) 65% - Electric Space Heating less than 4 Controlled Units f) 40% - Electric Space Heating for 4 or more Controlled Units Multifamily Dwelling - It shall be permissible to calculate the load of a feeder or service that supplies three or more dwelling units of a multifamily dwelling in accordance with the table if all the following conditions are met: 1. No dwelling unit is supplied by more than one feeder. 2. Each dwelling unit is equipped with electric cooking equipment. OUTSIDE BRANCH CIRCUITS AND FEEDERS Conductor Size and Supports a) Overhead Spans - Individual conductors shall not be smaller than the following: 1. For 600 volts, nominal, or less 1. 15m Length - 5.5 mm2 (2.6 mm. dia.) copper and 8.0 mm2 (3.2 mm. dia.) aluminum 2. Longer than 15m - 8.0 mm2 (3.2 mm. dia.) copper and 14 mm2 aluminum 2. For over 600 volts 1. Open Individual Conductors - 14 mm2 copper and 22 mm2 aluminum 2. Conductors in Cable - 8.0 mm2 (3.2 mm. dia.) copper and 14 mm2 aluminum b) Festoon Lighting - Overhead conductors for festoon lighting shall not be smaller than 3.5 mm2 (2.0 mm dia.) unless the conductors are supported by messenger wirings. 17 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 22 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) OPEN CONDUCTOR SPACING (CLEARANCES) - FEEDERS AND CONDUCTORS Conductor on Poles - Shall have a separation of not less than 300 mm where not placed on racks or brackets. a) Power conductors below communications conductors - 750 mm b) Power conductors alone or above communications conductors: 1. 300V or less - 600 mm 2. Over 300V- 750 mm c) Communications conductors below power conductors - Same as power conductors d) Communications conductors alone - No requirement OVERHEAD SERVICE Service Drop - The overhead service conductor from the last pole or other aerial support and including splices if any, connecting to the service entrance conductor in a building or other structures. Overhead Service Locations 1. Equipped with rain-tight service head. 2. Located above the point of attachment of the service-drop conductors. 3. Drip loops formed on individual conductors to prevent moistures. 4. Arranged that water will not enter service raceway or equipment. Overhead Service Drop Conductors - The minimum size of overhead service drop conductors: a) Copper - 8.0 mm2 (3.2 mm dia.) b) Aluminum or Copper Clad - 14 mm2 Clearance from Ground - Overhead spans of conductors not over 600V, nominal, shall have a clearance of not less than the following: a) 3000 mm - Above finished grade, sidewalks, pedestrians (150V per phase max.). And, at electric service entrance to buildings, also at the lowest point of the drip loop. b) 3600 mm - Over residential property, driveways, and commercial properties not subject to traffic where voltage does not exceeds 300V per phase max. c) 4500 mm - Over residential property, driveways, and commercial properties not subject to traffic where voltage exceeds over 300V per phase. d) 5500 mm - Over public streets, alleys, roads, parking areas subject to truck traffic, driveways, cultivated, grazing, forest, and orchard. e) 6900 mm - In any direction of the water level of swimming pools. Clearances from Buildings for Conductors of Not Over 600 Volts, Nominal a) Above Roofs - Shall not be less than 2500 mm above roof surface and maintained at a distance not less than 900 mm in all directions from the edge of the roof.  Voltage does not exceed 300V and the roof has a slope of 100 mm in 300 mm or greater - A reduction of 900 mm in clearance is permitted. b) From Non-Building or Non-Bridge Structures - from signs, chimneys, radio and television antennas, tanks - vertical, diagonal, and horizontal - shall not be less than 900 mm. c) Horizontal Clearances - Clearances shall not be less than 900 mm d) Finals Spans - Final spans of feeders or branch circuits: 1. Clearance from Windows - Shall be kept not less than 900 mm. 2. Vertical Clearance - 900 mm measured horizontally of, platforms or projections. 3. Building Openings - Overhead branch circuits shall not be installed beneath openings through which materials may be moved. 4. Zone for Fire Ladders - A clear space (zone) at least 1800 mm wide left adjacent of the building to facilitate rising of ladders when necessary for fire fighting. 18 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 23 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) 19 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 24 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) SERVICES Service Entrance - The service conductors between the terminal of the service equipment and point usually outside the building, clear of building walls, where joined by a taps or splices to the service drop. A building or other structure served be supplied by one service only Buildings or Structures requiring Additional Feeders/Service Entrance: a) Special Conditions - Additional feeder or branch circuits shall be permitted to the ff. 1. Fire pumps (high pressure) for the building 2. Emergency systems 3. Legally required standby systems 4. Optional standby systems 5. Parallel power production systems 6. Multiple sources of supply for the purpose of enhanced reliability b) Special Occupancies - By special permission, additional feeder or branch circuit shall be permitted: 1. Multiple-occupancy buildings where there is no available space for service equipment accessible to all occupancies. 2. A single building/structure sufficiently large to make two or more supplies necessary. c) Capacity Requirements - Where the capacity requirements are in excess of 2000 amperes at a supply voltage of 600Vor less d) Different Characteristics - Additional services shall be permitted for different voltages, frequencies, or phases, or for different uses, such as for different rate schedules. e) By Identification Conductors Considered Outside the Building - The conductors considered outside the building shall be in the following conditions: a) Installed under not less than 50 mm of concrete beneath a building/structure b) Encased in concrete or brick not less than 50 mm thick c) Installed in any vault construction d) installed in conduit and under not less than 450 mm of earth burial 20 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 25 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) UNDERGROUND SERVICE Service Lateral - the underground service conductors between the street main including any risers at a pole or other structure or from transformers, and the first point of connection to the service-entrance conductors in a terminal box or other enclosure, inside or outside the building wall. Where there is no terminal box, meter, or other enclosure, the point of connection is considered to be the point of entrance of the service conductors into the building. Clearance of Service Lateral: a) 600 mm - directly buried cable b) 150 mm - RMC or IMC installation c) 450 mm - PVC approved for direct burial without concrete encasement d) 450 mm - other approved raceway for direct burial 21 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 26 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) 22 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 27 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) Mounting Supports - Service cables shall be supported by straps or other approved means within 300 mm of every service head, gooseneck, or connection to a raceway or enclosure at intervals not exceeding 750 mm. Equipments Connected to the Supply Side Service Disconnect: a) Cable limiters or other current-limiting devices b) Meters and meter sockets (not in excess of 600V) c) Meter disconnect switches (not in excess of 600V) d) Fusible switches or circuit breakers e) Instrument transformers (current and voltage), impedance shunts, load management devices, arresters f) Taps used only to supply load management devices g) Solar photovoltaic systems, fuel cell systems, interconnected electric power production sources h) Control circuits for power-operable service disconnecting means i) Ground-fault protection systems or transient voltage surge suppressors j) Fusible disconnect switch or circuit breaker Services Exceeding 600 Volts, Nominal - Conductors not smaller than 14 mm2 unless in multi-conductor cable. Multi-conductor cable shall not be smaller than 8.0 mm2 (3.2 mm dia.). Maximum Number of Disconnects - Shall consists of not more than 6 switches or sets of circuit breakers, or a combination thereof shall be in a group of separate enclosures in a switchboard. Manually or Power Operable a) Manually operable - A manually operable switch or circuit breaker shall be equipped with a handle or other suitable operating means. b) Powered-operated switch - It can be manually or power-operable/circuit breaker, provided it can be opened by hand during power failure. Rating of Service Disconnecting Means: - The service disconnecting means shall have a rating not less than the load to be supplied and not lower than the specified in the following: a) One Circuit Installation- Supplying only limited loads of a single branch circuit; the service disconnecting means shall have a rating of not less than 15A. b) One Circuit Installation-Dwelling Unit - For dwelling units with a single branch circuit a service disconnect means of not less than 20A is permitted. c) Two-Circuit Installations - For installation of not more than 2 wire branch circuits, the service disconnecting means shall have a rating of not less than 30A. d) One Family Dwelling - The service disconnect shall have a rating of not less than 60A, 3-wire. e) All Others - Shall have a rating of not less than 30A. 23 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 28 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) OVERCURRENT PROTECTION Current-Limiting Overcurrent Protective Device - A device that, when interrupting currents in its current-limiting range, reduces the current flowing in the faulted circuit to a magnitude substantially less than that obtainable in the same circuit if the device were replaced with a solid conductor having comparable impedance. Tap Conductor - A conductor, other than a service conductor, that has overcurrent protection ahead of its point of supply that exceeds the value permitted for similar conductors that are protected. Standard Ampere Ratings - The standard ampere ratings for fuses and inverse time circuit breakers shall be considered 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600, 700, 800, 1000, 1200, 1600, 2000, 2500, 3000, 4000, 5000, and 6000 amperes. Additional standard ampere ratings for fuses shall be 1, 3, 6, 10, and 601. The use of fuses and inverse time circuit breakers with nonstandard ampere ratings shall be permitted. Fuses or Circuit Breakers in Parallel - Fuses and circuit breakers shall be permitted to be connected in parallel where they are factory assembled in parallel and listed as a unit. Individual fuses, circuit breakers, or combinations thereof shall not otherwise be connected in parallel. Thermal Devices - Thermal relays and other devices not designed to open short circuits or ground faults shall not be used for the protection of conductors against overcurrent due to short circuits or ground faults, but the use of such devices shall be permitted to protect motor branch-circuit conductors from overload if protected. Grounded Conductor - No overcurrent device shall be connected in series with any conductor that is intentionally grounded. Change in Size of Grounded Conductor - Where a change occurs in the size of the ungrounded conductor, a similar change shall be permitted to be made in the size of the grounded conductor. Locations in or in Premises a) Accessibility - Overcurrent devices shall be readily accessible and shall be installed so that the center grip of the handle switch at its highest position is not more than 2 meters from the floor. b) Occupancy - each occupant shall have ready access to all overcurrent devices protecting the conductors supplying that occupancy. c) Not Exposed in Physical Damage d) Not in Vicinity of Easily Ignitable Materials e) Not Located in Bathrooms f) Installed in a Vertical Position Circuit Breakers a) Method of Operation - Circuit breakers shall be trip free and capable of being closed and opened by manual operation. Their normal method of operation by other manual means, such as electrical or pneumatic, shall be permitted if means for manual operation are also provided. b) Indication - The indication of ―up‖ position of the handle is ―on‖ position and a ―down‖ position is indicating it is in ―off‖ position. c) Nontamperable - A circuit breaker shall be of such design that any alteration of its trip point (calibration) or the time required for its operation requires dismantling of the device or breaking of a seal for other than intended adjustments. 24 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 29 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) d) Marking 1. Durable and Visible - Circuit breakers shall be marked with their ampere rating in a manner that will be durable and visible after installation 2. Location - Circuit breaker rated at 100A or less and 600V or less shall have the ampere rating molded, stamped, etched or similarly marked into their handles. 3. Interrupting Rating - Each device with an interrupting rating other than 5000A shall have its interrupting rating shown on the circuit breaker. 4. Used as Switches - Circuit breakers used as switches in 120V and 277V fluorescent lighting circuits shall be listed and shall be marked SWD or HID. 5. Voltage Marking - Circuit breakers shall be marked with a voltage rating not less than the nominal system voltage that is indicative of their capability to interrupt fault currents between phases or phase to ground. Overcurrent Protection over 600V, Nominal a) Overcurrent Relays and Current Transformers - Circuit breakers used for overcurrent protection of 3-phase circuits shall have a minimum of 3 overcurrent relay elements operated from 3- current transformers. b) Fuses - a fuse shall be connected in series with each ungrounded conductor. GROUNDING AND BONDING Effective Ground-Fault Current Path - An intentionally constructed, permanent, low-impedance electrically conductive path designed and intended to carry current underground-fault conditions from the point of a ground fault on a wiring system to the electrical supply source and that facilitates the operation of the overcurrent protective device or ground fault detectors on high-impedance grounded systems. Ground Fault - An unintentional, electrically conducting connection between an ungrounded conductor of an electrical circuit and the normally non-current-carrying conductors, metallic enclosures, metallic raceways, metallic equipment, or earth. Ground-Fault Current Path - An electrically conductive path from the point of a ground fault on a wiring system through normally non-current carrying conductors, equipment, or the earth to the electrical supply source. Grounding Electrode Conductor - connects the equipment grounding conductors, the service- equipment enclosures to the grounding electrode(s) General Requirements for Grounding and Bonding: a) Electrical System Grounding - Shall have connections that limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines that will stabilize the voltage to earth. b) Grounding of Electrical Equipment - Non-current carrying conductive materials, electrical conductors, or equipment shall be connected to earth so as to limit the voltage to ground. c) Bonding of Electrical Equipment - Non-current carrying conductive materials forming part of such equipment connected together establishing an ―effective ground-fault current path”. d) Bonding of Electrically Conductive Material and Other Equipment - Electrically conductive materials that are likely to be energized shall be connected together establishing “effective ground-fault current path”. e) Effective Ground-Fault Current Path - A low impedance current path for the fault current to carry the maximum ground-fault current. Connection of Grounding and Bonding Equipment a) Connected by exothermic welding, listed pressure contactors, listed clamps. b) Connection devices or fittings that depend solely on solders shall not be used. c) Sheet metal screws shall not be used. d) Non-conductive coatings shall be removed such as paint, lacquer, and enamel. 25 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 30 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) Circuits Not To Be Grounded 1. Electric cranes operating over combustible fibers in Class III locations. 2. Circuits in health care facilities. 3. Circuits for equipment within electrolytic cell working zone. 4. Secondary circuits of lighting systems. Main Bonding Jumper and System Bonding Jumper 1. Copper or other corrosion-resistant material. 2. Wire, bus, screw, or similar suitable conductor. 3. Screws shall be identified with a green finish. Grounding Electrode Conductor for Multiple Separately Derived Systems - The common grounding electrode conductor shall not be smaller than 80 mm2 copper or 125 mm2 aluminum. Grounding Electrodes (Electrodes Permitted for Grounding) - The following listed shall be permitted to be grounding electrodes and shall be bonded together to form the grounding system which limits the voltage to ground: 1. Metal Underground Water Pipe - Any metal underground water pipe 3000 mm or more and electrically continuous to the points of connection of the grounding electrode conductor and the bonding conductors. 2. Metal Frame of the Building - 3000 mm or more of a single structure metal member in direct contact with earth or encased in concrete that is in direct contact with the earth. 3. Concrete Encased Electrode - An electrode encased by at least 50 mm of concrete located near the bottom of concrete foundation or footing. It has 6000 mm of one or more electrically conductive steel coated bars. 4. Ground Ring - Bare copper conductor not smaller than 30 mm2 encircling the building/structure. 6000 mm or more in length and buried at a depth not less than 750 mm 5. Rod and Pipe Electrodes - Rod and pipe electrodes shall not be less than 2400 mm in length. a) Electrodes of pipe or conduit shall not be smaller than 20 mm. b) Electrodes of iron or steel shall be at least 16 mm in diameter. 6. Plate Electrodes - Shall not expose (2ft 2) 0.186 m2 of surface to exterior. Iron or steel electrodes, 6 mm thick. Nonferrous metal electrodes, at least 1.5 mm thick. And, plate electrodes shall not be less than 750 mm below the earth’s surface. 7. Other Local Metal Underground Systems or Structures Electrodes Not Permitted for Grounding 1. Metal underground gas piping system 2. Aluminum electrodes Bonding of Services - The non-current carrying metal parts listed should be effectively bonded together: a) Service raceways, cable trays, cable framework, auxiliary gutters, service cable armor or sheath. b) Service enclosures containing service conductors, meter fittings, boxes, materials interposed in the service raceway or armor. c) Any metallic raceway or armor enclosing a grounding electrode. Equipment Bonding Jumpers a) Size - Equipment Bonding Jumper (Supply Side) - The minimum size of bonding jumper shall be 8.0 mm2 for copper and 14 mm2 for aluminum or copper-clad aluminum. b) Size - Equipment Bonding Jumper (Load Side) - The largest underground circuit conductors supplying the equipment shall not be smaller than 2.0 mm2 (1.6 mm. dia.). 26 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 31 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) Grounding Electrode Conductor for AC Systems Size of the Largest Underground Service-Entrance Size of Ground Electrode Conductor (mm2) Conductor or Equivalent Area for Parallel Cond. Aluminum or Aluminum or Copper Copper Copper-Clad Aluminum Copper-Clad Aluminum 30 or smaller 50 or smaller 8.0 (3.2) 14 38 or 50 60 or 80 14 22 60 or 80 100 or 125 22 30 Over 80 through 200 Over 125 through 250 30 50 Over 200 through 325 Over 250 through 400 50 80 Over 325 through 500 Over 400 through 850 60 100 Over 500 Over 850 80 125 Equipment Grounding and Equipment Grounding Conductors a) Equipment Fastened in Place or Connected by Permanent Wiring Methods (Fixed) - Exposed non- current carrying metal parts or fixed equipment that are likely to become energized shall be grounded: 1. Where within 2400 mm vertically or 1500 mm horizontally of ground or grounded metal objects and subject to contact by persons. 2. In a wet or damp location and not isolated. 3. Where in electrical contact with metal. 4. In hazardous locations. 5. Supplied by a metal-clad, metal sheathed metal-raceway, or other equipment grounding methods. 6. Operates with a terminal at over 150 volts to ground. b) Equipment Fastened in Place or Connected by Permanent Wiring Methods (Fixed) - Specific - Exposed, non-current carrying metal parts of the kinds of equipment and non-current carrying metal parts shall be grounded: 1. Switchboard Frames and Structures 2. Pipe Organs - generator and motor from frames in an electrically operated pipe organ. 3. Motor Frames 4. Enclosures for Motor Controllers 5. Elevators and Cranes 6. Garages, Theaters, and Motion Picture Studios 7. Electric Signs 8. Motion Picture Projection Equipment 9. Power-Limited Remote-Control, Signaling, and Fire Alarm Circuits 10. Luminaries (Lighting Fixtures) 11. Skid Mounted Equipment 12. Motor-Operated Water Pumps (including submersible type) 13. Metal Well Casings c) Equipment Connected by Cord and Plug 1. In hazardous locations 2. Operated at over 150 volts to ground 3. In residential and non residential occupancies:  Refrigerators, freezers, and air-conditioners  Clothes-washing, clothes-drying, dish-washing machines; kitchen waste disposer, IT equip. sump pumps and electrical aquarium equipments.  Hand-held motor-operated tools, stationary and fixed motor-operated tools, light industrial motor-operated tools. 27 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 32 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE)  Motor-operated appliances of the following types: hedge clippers, lawn mowers, snow blowers, and wet scrubbers.  Portable handlamps  Cord-and-plug connected appliances used in damp or wet locations  Tools likely to be used in wet or conductive locations d) Nonelectric Equipment - Equipments listed shall be grounded:  Frames and tracks of electrically operated cranes and hoists  Frames of non-electrically driven elevator cars to which electrical conductors are attached  Hand-operated metal shifting ropes or cable of electric elevators Identification of Equipment Grounding Conductors a) Shall be permitted to be bare, covered, or insulated. b) Green or green with one or more yellow stripes outer finish. c) Minimum size of equipment grounding conductor is 2.0 mm2 (1.6 mm. dia.) for copper and 3.5 mm2 (2.0 mm. dia.) for copper aluminum or copper-clad aluminum Identification of Wiring Device Terminals: 1. Green, not readily removable terminal screw with a hexagonal head. 2. Green, hexagonal, not readily removable terminal nut. 3. Green pressure wire connector. If the terminal is not visible, the conductor entrance hall shall be marked with the word green or ground, or letters ―G‖ or ―GR‖ or otherwise identified by distinctive green color. Size of Direct-Current Grounding Electrode Conductor: 1. Shall not be smaller than 8.0 mm2 for copper and 14 mm2 aluminum. 2. Shall not be smaller than the largest conductor. 3. Connected to a rod, piper, or plate electrode. 4. Connected to a concrete-encased electrode. 5. Connected to a ground ring. 28 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 33 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) Instrument, Meters and Relays: a) Such Cases should be Grounded: 1. Not on switchboards and at 300 volts or more. 2. On dead-front switchboards having no live parts in front of the panel. 3. On live-front switchboards having exposed live parts. Mats of insulating rubber should be provided for the operator where the voltage exceeds 150 volts. b) Instrument Grounding Conductor - The grounding conductor for secondary circuits of instrument transformers and for instrument cases shall not be smaller than 3.5 mm 2 (2.0 mm dia.) copper or 5.5 mm2 (2.6 mm dia.) for aluminum. SURGE ARRESTERS Surge Arrester - A protective device for limiting surge voltages by discharging or bypassing surge current, and it also prevents continued flow of follow current while remaining capable of repeating these functions. Surge Arrester Selection: a) Circuits of less than 1000 Volts - surge arresters installed on a circuit of less than 1000 volts shall comply with all of the following provisions: 1. The rating shall be equal to or greater than the maximum continuous phase-to-ground power frequency voltage available at the point of application. 2. Surge arresters installed on circuits of less than 1 000 volts shall be listed. 3. With a short circuit current rating and shall not be installed at a point on the system where the available fault current is in excess of that rating. 4. Shall not be installed on ungrounded systems, impedance grounded systems, or corner grounded delta systems unless listed specifically for use on these systems. b) Circuits of 1kV and over -Silicon Carbide Types - The rating of a silicon carbide-type surge arrester shall not be less than 125% of the maximum continuous phase-to-ground voltage. TRANSIENT VOLTAGE SURGE SUPPRESSOR (TVSS) Transient Voltage Surge Suppressor (TVSS) - A protective device for limiting transient voltages by diverting or limiting surge current; it also prevents continued flow of follow current while remaining capable of repeating these functions. Uses Not Permitted - A transient voltage surge suppressor shall not be installed in the following: 1. Circuits exceeding 600 volts. 2. On ungrounded systems, impedance grounded systems, or corner grounded delta systems unless listed specifically for use on these systems. 3. Where the rating of the TVSS is less than the maximum continuous phase-to-ground power frequency voltage available at the point of application. Conductor Size - Line and ground connecting conductors shall not be smaller than 2.0 mm2 (1.6 mm dia.) copper or 3.5 mm2 (2.0 mm dia.) aluminum. 29 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 34 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) PROTECTION AGAINST LIGHTING Definition: Lighting Protection System - A complete system of air terminals, conductors, ground terminals, interconnecting conductors, arresters, and other connectors or fittings required to complete the system. Rods and Points - Generic terms for the component parts. Air Terminal - Capable to drawing lighting discharge to it in preference to vulnerable parts of the protected area. It may consist of a pointed, solid, or tubular rod or one with special design and material provided with a mounting base having a proper conductor connection. Class I Materials - All conductors, fittings, and fixture for protection not exceeding 23 m in height. Class II Materials - All conductors, fittings and fixtures for protection exceeding 23 m in height; or one which has a structural steel frame, of any height. Copper-Clad Steel - Steel with a coating of copper to bond it Counterpoise (ground) - A conductor encircling a building and inter-connecting all ground terminals Fastener - An attachment to secure the conductor to the structure Flame Protection - Self-closing gage hatches, vapor seals, pressure-vacuum breather valves, flame arresters, or other reasonably effective means to minimize the possibility of flame entering the vapor space of a tank. Flammable Vapors - The vapors given from a flammable liquid at or above its flash point. Flash Point - The minimum temperature at which it gives off vapor in sufficient concentration to form an ignitable mixture with air near the surface of the liquid within the vessel. High-Rise Building - A building over 23m in height. Metal Body of Conductance - Metal objects at the flat roof level subject to direct lighting stroke. Metal Body of Inductance - Metal objects located 2000 mm of a conductor subject to buildup of potential. Metal-Clad Building - Building with either sides or roof made of or covered with sheet metal. Metal-Framed Building - Building with electrically continuous framing of sufficient size and conductivity. Sideflash - A spark between nearby metallic objects to lighting protection system or to ground. Spark Gap - Any short air space between two conductors electrically insulated to each other. Stack, Heavy-Duty - A smoke/vent stack with greater than 0.32 m2 and the height is greater than 23 m. Vapor Openings - Openings for tank breathing, tank gaging, and fire fighting. Zone of Protection - Provided by a grounded air terminal or mast or overhead ground wire which is immune to direct strokes of lighting. Protection for Ordinary Buildings - An ordinary building is one of common or conventional design and construction used for ordinary purposes, whether commercial, farm, industrial, institutional, or residential. a) Classifications 1. Class I ordinary buildings - Less than 23 m in height. 2. Class II ordinary buildings - More than 23 m in height. b) Materials - The materials of which protection systems are made shall be resistant to corrosion or shall be acceptably protected against corrosion. 1. Copper - It shall be grade ordinarily designed with 98% conductivity when annealed. 2. Copper Alloys - It shall be substantially resistant to corrosion as copper. 3. Aluminum - When aluminum is used, care shall be taken not to use it in contact with the earth or elsewhere where it will rapidly deteriorate. c) Configuration  Gable, Hip, Broken Gable, Flat, Mansard, Gambrel 30 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 35 of 106  PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) Terminals on Roofs a) Flat or Gently Sloping Roofs - Additional air terminals at intervals not exceeding 15m. Gently sloping are roofs having a span of 12m/less and a pitch of 1/8 or less or exceeding 12m with 1/4 pitch or less. b) Lower Roofs - One-to-one zone protection for buildings which exceed 15m above grade. One-to-two zone protection for buildings not exceeding 15m. c) Dormers - Higher than the main roof shall be protected with air terminals along end ridges. d) Roofs with Intermediate Ridges - Air terminals not exceeding 7600mm for roofs with parallel ridges. e) Irregular Roof Lines - Air terminals located within 600mm of the outermost projection of the roof edge. f) Open Areas in Flat Roofs - Shall be protected if their perimeter exceeds 92 m provided either rectangular dimension exceeds 15 m. g) Doomed Or Curved Structures - Air terminal located at the apex of the curve or dome. h) Chimneys - Air terminals shall be placed with 4.8 mm thick. Chimney air terminals shall be attached to the chimney so that no outside corner of the chimney is more than 600 mm from an air terminal. Gradual Bends - No bend of angle of less than 90 degrees nor shall have a radius of bend less than 230 mm Two Way Path Exceptions 1. One-Way Drops - Permitted w/o an extra downlead provided lower roof conductor not more than 12m. 2. Dead Ends - Air terminals may be ―dead ended‖ with only one path provided the conductor run from the air terminal to a main conductor is not more than 4900 mm in total length. Down Conductors - At least two down conductors shall be provided of any kind of structure, including steeples. 1. Number of Down Conductor - Average distance between conductors shall not exceed 30m. Irregularly shaped structures may require extra down conductors to provide a two-way path to ground. 2. Protecting Down Conductors - Down conductors located in runways, driveways, school playgrounds, cattle yards, public walks shall be guarded to prevent from physical damage. Grounding 1. Ground Terminal (Rods) - Shall be not less than 12.7 mm in dia. and 2400 mm long. Rods shall be copper-clad steel, solid copper or stainless steel. 2. Ground Rod Clamps - Clamps shall make contact with the ground rod for a distance of 38 mm. Clamps shall be secured with at least two bolts or cap screws. Common Grounds - All grounding mediums shall be bonded together which includes electric, telephone, antenna. Piping system including water service, well casings within 7600 mm, gas piping, underground conduits, underground liquefied petroleum-gas piping systems. Metal Bodies a) Bonding Requirements for Metal Bodies of Conductance - Bonded to the system having a surface contact area of not less than 0.0019 m2 b) Bonding Requirements for Metal Bodies of Inductance - Bonded to their closes point using secondary bonding conductors and fittings. Connections made within 1800 mm. Anchors - Masonry anchors shall have a diameter of not less than 6.4 mm and shall be set with care. Fit shall be tight against moisture and the effect of frost and capable of withstanding a pull test of 445N. Splicers and Clamps - Splicers and clamps shall be permitted to be connected to ―end-to-end‖ ―tee‖ or ―Y‖ splices and shall withstand a pull test of 890N. 31 | PEC Reviewer - Property of Andryn Jill Dumbrique Beltran (REE) COPYRIGHT 2014 ANDRYN JILL D. BELTRAN, REE, VIGAN ILOCOS SUR, [email protected] Page 36 of 106