Philippine Electrical Code Part 1/Chapter 2. Wiring and Protection/Article 2.25 - Outside Branch Circuits And Feeders

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Article 2.25 - Outside Branch Circuits And Feeders

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This is not an official copy of the Philippine Electrical Code. This is a Design Guide according to the provisions of the Philippine Electrical Code. It also provides interpretation and annotations of the clauses of the Philippine Electrical Code. Any information, interpretation and/or annotation presented herein are based on personal opinion of the authors and does not represent the official interpretation of the Philippine Electrical Code.


While the authors have used good faith and efforts to ensure that the information and instructions contained in this work are accurate, the authors disclaim all responsibility for errors or omissions, including without limitation responsibility for damages resulting from the use of or reliance on this work. Use of the information and instructions contained in this work is at your own risk. If any contents or other technology this work contains or describes is subject to open source licenses or the intellectual property rights of others, it is your responsibility to ensure that your use thereof complies with such licenses and/or rights

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Contents


2.25.1 General.

2.25.1.1 Scope.

This article covers requirements for outside branch circuits and feeders run on or between buildings, structures, or poles on the premises; and electric equipment and wiring for the supply of utilization equipment that is located on or attached to the outside of buildings, structures, or poles.

FPN: For additional information on wiring over 600 volts, see ANSI C2-2002, National Electrical Safety Code.

2.25.1.2 Other Articles.

Application of other articles, including additional requirements to specific cases of equipment and conductors, is shown in Table 2.25.1.2.

2.25.1.3 Calculation of Loads 600 Volts, Nominal, or Less.

(a) Branch Circuits.

The load on outdoor branch circuits shall be as determined by 2.20.2.1.

(b) Feeders.

The load on outdoor feeders shall be as determined by Part 2.20.3.

2.25.1.4 Conductor Covering.

Where within 3 000 mm of any building or structure other than supporting poles or towers, open individual (aerial) overhead conductors shall be insulated or covered. Conductors in cables or raceways, except Type MI cable, shall be of the rubber-covered type or thermoplastic type and, in wet locations, shall comply with 3.10.1.8. Conductors for festoon lighting shall be of the rubber-covered or thermoplastic type.

Exception: Equipment grounding conductors and grounded circuit conductors shall be permitted to be bare or covered as specifically permitted elsewhere in this Code.

Table 2.25.1.2 Other Articles
Equipment/Conductors Article
Branch circuits 2.1
Class 1, Class 2, and Class 3 remote-control, signaling, and power-limited circuits 7.25
Communications circuits 8.0
Community antenna television and radio distribution systems 8.20
Conductors for general wiring 3.10
Electrically driven or controlled irrigation machines 6.75
Electric signs and outline lighting 6.0
Feeders 2.15
Fire alarm systems 7.60
Fixed outdoor electric deicing and snow-melting equipment 4.26
Floating buildings 5.53
Grounding 2.50
Hazardous (classified) locations 5.0
Hazardous (classified) locations — specific 5.10
Marinas and boatyards 5.55
Messenger supported wiring 3.96
Mobile homes, manufactured homes, and mobile home parks 5.50
Open wiring on insulators 3.98
Over 600 volts, general 4.90
Overcurrent protection 2.40
Radio and television equipment 8.10
Services 2.30
Solar photovoltaic systems 6.90
Swimming pools, fountains, and similar installations 6.80
Use and identification of grounded conductors 2.0


2.25.1.5 Size of Conductors 600 Volts, Nominal, or Less.

The ampacity of outdoor branch-circuit and feeder conductors shall be in accordance with 3.10.1.15 based on loads as determined under 2.20.2.1 and Part 2.20.3.

2.25.1.6 Conductor Size and Support.

(a) Overhead Spans.

Open individual conductors shall not be smaller than the following:

(1) For 600 volts, nominal, or less, 5.5 mm 2 (2.6 mm dia.) copper or 8.0 mm 2 (3.2 mm dia.) aluminum for spans up to 15 m in length, and 8.0 mm 2 (3.2 mm dia.) copper or 14 mm 2 aluminum for a longer span unless supported by a messenger wire
(2) For over 600 volts, nominal, 14 mm 2 copper or 22 mm 2 aluminum where open individual conductors, and 8.0 mm 2 (3.2 mm dia.) copper or 14 mm 2 aluminum where in cable.
(b) Festoon Lighting.

Overhead conductors for festoon lighting shall not be smaller than 3.5 mm 2 (2.0 mm dia.) unless the conductors are supported by messenger wires. In all spans exceeding 12 m, the conductors shall be supported by messenger wire. The messenger wire shall be supported by strain insulators. Conductors or messenger wires shall not be attached to any fire escape, downspout, or plumbing equipment.

2.25.1.7 Lighting Equipment Installed Outdoors.

(a) General.

For the supply of lighting equipment installed outdoors, the branch circuits shall comply with Article 2.10 and 2.25.1.7(b) through (d).

(b) Common Neutral.

The ampacity of the neutral conductor shall not be less than the maximum net computed load current between the neutral and all ungrounded conductors connected to any one phase of the circuit.

(c) 277 Volts to Ground.

Circuits exceeding 120 volts, nominal, between conductors and not exceeding 277 volts, nominal, to ground shall be permitted to supply luminaires (lighting fixtures) for illumination of outdoor areas of industrial establishments, office buildings, schools, stores, and other commercial or public buildings where the luminaires (fixtures) are not less than 900 mm from windows, platforms, fire escapes, and the like.

(d) 600 Volts Between Conductors.

Circuits exceeding 277 volts, nominal, to ground and not exceeding 600 volts, nominal, between conductors shall be permitted to supply the auxiliary equipment of electric-discharge lamps in accordance with 2.10.1.6(d)(1).

2.25.1.10 Wiring on Buildings.

The installation of outside wiring on surfaces of buildings shall be permitted for circuits of not over 600 volts, nominal, as open wiring on insulators, as multiconductor cable, as Type MC cable, as Type MI cable, as messenger supported wiring, in rigid metal conduit, in intermediate metal conduit, in rigid nonmetallic conduit, in cable trays, as cablebus, in wireways, in auxiliary gutters, in electrical metallic tubing, in flexible metal conduit, in liquidtight flexible metal conduit, in liquidtight flexible nonmetallic conduit, and in busways. Circuits of over 600 volts, nominal, shall be installed as provided in 3.0.2.7.

2.25.1.11 Circuit Exits and Entrances.

Where outside branch and feeder circuits leave or enter a building, the requirements of 2.30.4.13 and 2.30.4.15 shall apply.

2.25.1.12 Open-Conductor Supports.

Open conductors shall be supported on glass or porcelain knobs, racks, brackets, or strain insulators.

2.25.1.14 Open-Conductor Spacings.

(a) 600 Volts, Nominal, or Less.

Conductors of 600 volts, nominal, or less, shall comply with the spacings provided in Table 2.30.4.12(c).

(b) Over 600 Volts, Nominal.

Conductors of over 600 volts, nominal, shall comply with the spacings provided in Sections 1.10.3.7 and 4.90.2.4.

(c) Separation from Other Circuits.

Open conductors shall be separated from open conductors of other circuits or systems by not less than 100 mm.

(d) Conductors on Poles.

Conductors on poles shall have a separation of not less than 300 mm where not placed on racks or brackets. Conductors supported on poles shall provide a horizontal climbing space not less than the following:

(1) Power conductors below communications conductors — 750 mm
(2) Power conductors alone or above communications conductors:
a. 300 volts or less — 600 mm
b. Over 300 volts — 750 mm
(3) Communications conductors below power conductors — same as power conductors
(4) Communications conductors alone — no requirement

2.25.1.15 Supports over Buildings.

Supports over a building shall be in accordance with 2.30.2.8.

2.25.1.16 Attachment to Buildings.

(a) Point of Attachment.

The point of attachment to a building shall be in accordance with 2.30.2.5.

(b) Means of Attachment.

The means of attachment to a building shall be in accordance with 2.30.2.6.

2.25.1.17 Masts as Supports.

Where a mast is used for the support of final spans of feeders or branch circuits, it shall be of adequate strength or be supported by braces or guys to withstand safely the strain imposed by the overhead drop. Where raceway-type masts are used, all raceway fittings shall be identified for use with masts. Only the feeder or branch circuit conductors specified within this section shall be permitted to be attached to the feeder and/or branch circuit mast.

2.25.1.18 Clearance from Ground.

Overhead spans of open conductors and open multiconductor cables of not over 600 volts, nominal, shall have a clearance of not less than the following:

(1) 3 000 mm — above finished grade, sidewalks, or from any platform or projection from which they might be reached where the voltage does not exceed 150 volts to ground and accessible to pedestrians only

(2) 3 600 mm — over residential property and driveways, and those commercial areas not subject to truck traffic where the voltage does not exceed 300 volts to ground

(3) 4 500 mm — for those areas listed in the 3 600 mm classification where the voltage exceeds 300 volts to ground

(4) 5 500 mm — over public streets, alleys, roads, parking areas subject to truck traffic, driveways on other than residential property, and other land traversed by vehicles, such as cultivated, grazing, forest, and orchard

2.25.1.19 Clearances from Buildings for Conductors of Not Over 600 Volts, Nominal.

(a) Above Roofs.

Overhead spans of open conductors and open multiconductor cables shall have a vertical clearance of not less than 2 400 mm above the roof surface. The vertical clearance above the roof level shall be maintained for a distance not less than 900 mm in all directions from the edge of the roof.

Exception No. 1: The area above a roof surface subject to pedestrian or vehicular traffic shall have a vertical clearance from the roof surface in accordance with the clearance requirements of 2.25.1.18.

Exception No. 2: Where the voltage between conductors does not exceed 300, and the roof has a slope of 100 mm in 300 mm or greater, a reduction in clearance to 900 mm shall be permitted.

Exception No. 3: Where the voltage between conductors does not exceed 300, a reduction in clearance above only the overhanging portion of the roof to not less than 450 mm shall be permitted if (1) not more than 1 800 mm of the conductors, 1 200 mm horizontally, pass above the roof overhang and (2) they are terminated at a through-the- roof raceway or approved support.

Exception No. 4: The requirement for maintaining the vertical clearance 900 mm from the edge of the roof shall not apply to the final conductor span where the conductors are attached to the side of a building.

(b) From Nonbuilding or Nonbridge Structures.

From signs, chimneys, radio and television antennas, tanks, and other nonbuilding or nonbridge structures, clearances — vertical, diagonal, and horizontal — shall not be less than 900 mm.

(c) Horizontal Clearances.

Clearances shall not be less than 900 mm.

(d) Final Spans.

Final spans of feeders or branch circuits shall comply with 2.25.1.19(d)(1), (d)(2), and (d)(3).

(1) Clearance from Windows.

Final spans to the building they supply, or from which they are fed, shall be permitted to be attached to the building, but they shall be kept not less than 900 mm from windows that are designed to be opened, and from doors, porches, balconies, ladders, stairs, fire escapes, or similar locations. Exception: Conductors run above the top level of a window shall be permitted to be less than the 900 mm requirement.

(2) Vertical Clearance.

The vertical clearance of final spans above, or within 900 mm measured horizontally of, platforms, projections, or surfaces from which they might be reached shall be maintained in accordance with 2.25.1.18.

(3) Building Openings.

The overhead branch-circuit and feeder conductors shall not be installed beneath openings through which materials may be moved, such as openings in farm and commercial buildings, and shall not be installed where they obstruct entrance to these buildings’ openings.

(e) Zone for Fire Ladders.

Where buildings exceed three stories or 15 m in height, overhead lines shall be arranged, where practicable, so that a clear space (or zone) at least 1 800 mm wide will be left either adjacent to the buildings or beginning not over 2 400 mm from them to facilitate the raising of ladders when necessary for fire fighting.

2.25.1.20 Mechanical Protection of Conductors.

Mechanical protection of conductors on buildings, structures, or poles shall be as provided for services in 2.30.4.11.

2.25.1.21 Multiconductor Cables on Exterior Surfaces of Buildings.

Supports for multiconductor cables on exterior surfaces of buildings shall be as provided in 2.30.4.12.

2.25.1.22 Raceways on Exterior Surfaces of Buildings or Other Structures.

Raceways on exteriors of buildings or other structures shall be arranged to drain and shall be raintight in wet locations. Exception: Flexible metal conduit, where permitted in 3.48.2.3(1), shall not be required to be raintight.

2.25.1.24 Outdoor Lampholders.

Where outdoor lampholders are attached as pendants, the connections to the circuit wires shall be staggered. Where such lampholders have terminals of a type that puncture the insulation and make contact with the conductors, they shall be attached only to conductors of the stranded type.

2.25.1.25 Location of Outdoor Lamps.

Locations of lamps for outdoor lighting shall be below all energized conductors, transformers, or other electric utilization equipment, unless either of the following apply:

(1) Clearances or other safeguards are provided for relamping operations.

(2) Equipment is controlled by a disconnecting means that can be locked in the open position.

2.25.1.26 Vegetation as Support.

Vegetation such as trees shall not be used for support of overhead conductor spans.

2.25.2 More Than One Building or Other Structure

2.25.2.1 Number of Supplies.

Where more than one building or other structure is on the same property and under single management, each additional building or other structure that is served by a branch circuit or feeder on the load side of the service disconnecting means shall be supplied by only one feeder or branch circuit unless permitted in 2.25.2.1(a) through (e). For the purpose of this section, a multiwire branch circuit shall be considered a single circuit.

(a) Special Conditions

Additional feeders or branch circuits shall be permitted to supply the following:

(1) Fire pumps
(2) Emergency systems
(3) Legally required standby systems
(4) Optional standby systems
(5) Parallel power production systems
(6) Systems designed for connection to multiple sources of supply for the purpose of enhanced reliability
(b) Special Occupancies.

By special permission, additional feeders or branch circuits shall be permitted for either of the following:

(1) Multiple-occupancy buildings where there is no space available for supply equipment accessible to all occupants
(2) A single building or other structure sufficiently large to make two or more supplies necessary
(c) Capacity Requirements.

Additional feeders or branch circuits shall be permitted where the capacity requirements are in excess of 2000 amperes at a supply voltage of 600 volts or less.

(d) Different Characteristics.

Additional feeders or branch circuits shall be permitted for different voltages, frequencies, or phases or for different uses, such as control of outside lighting from multiple locations.

(e) Documented Switching Procedures.

Additional feeders or branch circuits shall be permitted to supply installations under single management where documented safe switching procedures are established and maintained for disconnection.

2.25.2.2 Disconnecting Means.

Means shall be provided for disconnecting all ungrounded conductors that supply or pass through the building or structure.

2.25.2.3 Location.

The disconnecting means shall be installed either inside or outside of the building or structure served or where the conductors pass through the building or structure. The disconnecting means shall be at a readily accessible location nearest the point of entrance of the conductors. For the purposes of this section, the requirements in 2.30.1.6 shall be utilized.

Exception No. 1: For installations under single management, where documented safe switching procedures are established and maintained for disconnection, and where the installation is monitored by qualified individuals, the disconnecting means shall be permitted to be located elsewhere on the premises.

Exception No. 2: For buildings or other structures qualifying under the provisions of Article 6.85, the disconnecting means shall be permitted to be located elsewhere on the premises.

Exception No. 3: For towers or poles used as lighting standards, the disconnecting means shall be permitted to be located elsewhere on the premises.

Exception No. 4: For poles or similar structures used only for support of signs installed in accordance with Article 6.0, the disconnecting means shall be permitted to be located elsewhere on the premises.

2.25.2.4 Maximum Number of Disconnects.

(a) General.

The disconnecting means for each supply permitted by 2.25.2.1 shall consist of not more than six switches or six circuit breakers mounted in a single enclosure, in a group of separate enclosures, or in or on a switchboard. There shall be no more than six disconnects per supply grouped in any one location.

Exception: For the purposes of this section, disconnecting means used solely for the control circuit of the ground-fault protection system, or the control circuit of the power-operated supply disconnecting means, installed as part of the listed equipment, shall not be considered a supply disconnecting means.

(b) Single-Pole Units.

Two or three single-pole switches or breakers capable of individual operation shall be permitted on multiwire circuits, one pole for each ungrounded conductor, as one multipole disconnect, provided they are equipped with handle ties or a master handle to disconnect all ungrounded conductors with no more than six operations of the hand.

2.25.2.5 Grouping of Disconnects.

(a) General.

The two to six disconnects as permitted in 2.25.2.4 shall be grouped. Each disconnect shall be marked to indicate the load served.

Exception: One of the two to six disconnecting means permitted in 2.25.2.4, where used only for a water pump also intended to provide fire protection, shall be permitted to be located remote from the other disconnecting means.

(b) Additional Disconnecting Means.

The one or more additional disconnecting means for fire pumps or for emergency, legally required standby or optional standby system permitted by 2.25.2.1 shall be installed sufficiently remote from the one to six disconnecting means for normal supply to minimize the possibility of simultaneous interruption of supply.

2.25.2.6 Access to Occupants.

In a multiple-occupancy building, each occupant shall have access to the occupant’s supply disconnecting means.

Exception: In a multiple-occupancy building where electric supply and electrical maintenance are provided by the building management and where these are under continuous building management supervision, the supply disconnecting means supplying more than one occupancy shall be permitted to be accessible to authorized management personnel only.

2.25.2.7 Suitable for Service Equipment.

The disconnecting means specified in 2.25.2.2 shall be suitable for use as service equipment. Exception: For garages and outbuildings on residential property, a snap switch or a set of 3-way or 4-way snap switches shall be permitted as the disconnecting means.

2.25.2.8 Identification.

Where a building or structure has any combination of feeders, branch circuits, or services passing through it or supplying it, a permanent plaque or directory shall be installed at each feeder and branch-circuit disconnect location denoting all other services, feeders, or branch circuits supplying that building or structure or passing through that building or structure and the area served by each.

Exception No. 1: A plaque or directory shall not be required for large-capacity multibuilding industrial installations under single management, where it is ensured that disconnection can be accomplished by establishing and maintaining safe switching procedures.

Exception No. 2: This identification shall not be required for branch circuits installed from a dwelling unit to a second building or structure.

2.25.2.9 Disconnect Construction.

Disconnecting means shall meet the requirements of 2.25.2.9(a) through (d).

Exception: For garages and outbuildings on residential property, snap switches or sets of 3-way or 4-way snap switches shall be permitted as the disconnecting means.

(a) Manually or Power Operable.

The disconnecting means shall consist of either (1) a manually operable switch or a circuit breaker equipped with a handle or other suitable operating means or (2) a power-operable switch or circuit breaker, provided the switch or circuit breaker can be opened by hand in the event of a power failure.

(b) Simultaneous Opening of Poles.

Each building or structure disconnecting means shall simultaneously disconnect all ungrounded supply conductors that it controls from the building or structure wiring system.

(c) Disconnection of Grounded Conductor.

Where the building or structure disconnecting means does not disconnect the grounded conductor from the grounded conductors in the building or structure wiring, other means shall be provided for this purpose at the location of disconnecting means. A terminal or bus to which all grounded conductors can be attached by means of pressure connectors shall be permitted for this purpose.

In a multisection switchboard, disconnects for the grounded conductor shall be permitted to be in any of the switchboard, provided any such switchboard is marked.

(d) Indicating.

The building or structure disconnecting means shall plainly indicate whether it is in the open or closed position.

2.25.2.10 Rating of Disconnect.

The feeder or branch-circuit disconnecting means shall have a rating of not less than the load to be supplied, determined in accordance with Parts 2.20.1 and 2.20.2 for branch circuits, Parts 2.20.3 or 2.20.4 for feeders, or Part 2.20.5 for farm loads. In no case shall the rating be lower than specified in 2.25.2.10(a), (b), (c), or (d).

(a) One-Circuit Installation.

For installations to supply only limited loads of a single branch circuit, the branch circuit disconnecting means shall have a rating of not less than 15 amperes.

(b) Two-Circuit Installations.

For installations consisting of not more than two 2-wire branch circuits, the feeder or branch-circuit disconnecting means shall have a rating of not less than 30 amperes.

(c) One-Family Dwelling.

For a one-family dwelling, the feeder disconnecting means shall have a rating of not less than 100 amperes, 3-wire.

(d) All Others.

For all other installations, the feeder or branch- circuit disconnecting means shall have a rating of not less than 60 amperes.

2.25.2.11 Access to Overcurrent Protective Devices.

Where a feeder overcurrent device is not readily accessible, branch-circuit overcurrent devices shall be installed on the load side, shall be mounted in a readily accessible location, and shall be of a lower ampere rating than the feeder overcurrent device.

2.25.3 Over 600 Volts

2.25.3.1 Sizing of Conductors.

The sizing of conductors over 600 volts shall be in accordance with 2.10.2.1(b) for branch circuits and 2.15.1.2(b) for feeders.

2.25.3.2 Isolating Switches.

Where oil switches or air, oil, vacuum, or sulfur hexafluoride circuit breakers constitute a building disconnecting means, an isolating switch with visible break contacts and meeting the requirements of 2.30.8.5(b), (c), and (d) shall be installed on the supply side of the disconnecting means and all associated equipment.

Exception: The isolating switch shall not be required where the disconnecting means is mounted on removable truck panels or metal- enclosed switchgear units that cannot be opened unless the circuit is disconnected and that, when removed from the normal operating position, automatically disconnect the circuit breaker or switch from all energized parts.

2.25.3.3 Location.

A building or structure disconnecting means shall be located in accordance with 2.25.2.3, or it shall be electrically operated by a similarly located remote-control device.

2.25.3.4 Type.

Each building or structure disconnect shall simultaneously disconnect all ungrounded supply conductors it controls and shall have a fault-closing rating not less than the maximum available short-circuit current available at its supply terminals.

Where fused switches or separately mounted fuses are installed, the fuse characteristics shall be permitted to contribute to the fault closing rating of the disconnecting means.

2.25.3.11 Clearances over Roadways, Walkways, Rail, Water, and Open Land.

(a) 22 kV Nominal to Ground or Less.

The clearances over roadways, walkways, rail, water, and open land for conductors and live parts up to 22 kV nominal to ground or less shall be not less than the values shown in Table 2.25.3.11.

(b) Over 22 kV Nominal to Ground.

Clearances for the categories shown in Table 2.25.3.11 shall be increased by 10 mm (0.4 in.) per kV above 22,000 volts.

(c) Special Cases.

For special cases, such as where crossings will be made over lakes, rivers, or areas using large vehicles such as mining operations, specific designs shall be engineered considering the special circumstances and shall be approved by the authority having jurisdiction.

FPN: For additional information, see ANSI C2-2002, National Electrical Safety Code.

2.25.3.12 Clearances over Buildings and Other Structures.

(a) 22 kV Nominal to Ground or Less.

The clearances over buildings and other structures for conductors and live parts up to 22 kV, nominal, to ground or less shall be not less than the values shown in Table 2.25.3.12.

(b) Over 22 kV Nominal to Ground.

Clearances for the categories shown in Table 2.25.3.12 shall be increased by 10 mm (0.4 in.) per kV above 22,000 volts.

FPN: For additional information, see ANSI C2-2002, National Electrical Safety Code.

Table 2.25.3.11 Clearances over Roadways, Walkways, Rail, Water, and Open Land
Location Clearance (m)
Open land subject to vehicles, cultivation, or grazing 5.6
Roadways, driveways, parking lots, and alleys 5.6
Walkways 4.1
Rails 8.1
Spaces and ways for pedestrians and restricted traffic 4.4
Water areas not suitable for boating 5.2


Table 2.25.3.12 Clearances over Buildings and Other Structures
Clearance from Conductors or Live Parts from: Horizontal (m) Vertical (m)
Building walls, projections, and windows 2.3 -
Balconies, catwalks, and similar areas accessible to people 2.3 4.1
Over or under roofs or projections not readily accessible to people - 3.8
Over roofs accessible to vehicles but not trucks - 4.1
Over roofs accessible to trucks 2.3 5.6
Other structures 2.3 -


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