Philippine Electrical Code Part 1/Chapter 2. Wiring and Protection/Article 2.15 - Feeders

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Article 2.15 - 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.


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2.15.1.1 Scope.

This article covers the installation requirements, overcurrent protection requirements, minimum size, and ampacity of conductors for feeders supplying branch-circuit loads. Exception: Feeders for electrolytic cells as covered in 6.68.1.3(c)(1) and (c)(4).

2.15.1.2 Minimum Rating and Size.

(a) Feeders Not More Than 600 Volts.
(1) General.

Feeder conductors shall have an ampacity not less than required to supply the load as calculated in Parts 2.20.3, 2.20.4, and 2.20.5. The minimum feeder-circuit conductor size, before the application of any adjustment or correction factors, shall have an allowable ampacity not less than the noncontinuous load plus 125 percent of the continuous load.

Exception: Where the assembly, including the overcurrent devices protecting the feeder(s), is listed for operation at 100 percent of its rating, the allowable ampacity of the feeder conductors shall be permitted to be not less than the sum of the continuous load plus the noncontinuous load.

The size of the feeder circuit grounded conductor shall not be smaller than that required by 2.50.6.13, except that 2.50.6.13(f) shall not apply where grounded conductors are run in parallel. Additional minimum sizes shall be as specified in 2.15.1.2(a)(2) and (a)(3) under the conditions stipulated.

(2) Ampacity Relative to Service Conductors.

The feeder conductor ampacity shall not be less than that of the service conductors where the feeder conductors carry the total load supplied by service conductors with an ampacity of 55 amperes or less.

(3) Individual Dwelling Unit or Mobile Home Conductors.

Feeder conductors for individual dwelling units or mobile homes need not be larger than service conductors. Paragraph 3.10.1.15(b)(6) shall be permitted to be used for conductor size

FPN No. 1: See Examples D1 through D12 in Appendix D.

FPN No. 2: Conductors for feeders as defined in Article 1.0, sized to prevent a voltage drop exceeding 3 percent at the farthest outlet of power, heating, and lighting loads, or combinations of such loads, and where the maximum total voltage drop on both feeders and branch circuits to the farthest outlet does not exceed 5 percent, will provide reasonable efficiency of operation.

FPN No. 3: See 2.10.2.1(a), FPN No. 4, for voltage drop for branch circuits.

(b) Feeders Over 600 Volts.

The ampacity of conductors shall be in accordance with 3.10.1.15 and 3.10.1.60 as applicable. Where installed, the size of the feeder circuit grounded conductor shall not be smaller than that required by 2.50.6.13, except that 2.50.6.13(f) shall not apply where grounded conductors are run in parallel. Feeder conductors over 600 volts shall be sized in accordance with 2.15.1.2(b)(1), (b)(2), or (b)(3).

(1) Feeders Supplying Transformers.

The ampacity of feeder conductors shall not be less than the sum of the nameplate ratings of the transformers supplied when only transformers are supplied.

(2) Feeders Supplying Transformers and Utilization Equipment.

The ampacity of feeders supplying a combination of transformers and utilization equipment shall not be less than the sum of the nameplate ratings of the transformers and 125 percent of the designed potential load of the utilization equipment that will be operated simultaneously.

(3) Supervised Installations.

For supervised installations, feeder conductor sizing shall be permitted to be determined by licensed electrical practitioner or non licensed electrical practitioner under the supervision of a licensed electrical practitioner. Supervised installations are defined as those portions of a facility where all of the following conditions are met:

a. Conditions of design and installation are provided under engineering supervision.
b. Licensed electrical practitioner or non licensed electrical practitioner under the supervision of a licensed electrical practitioner with documented training and experience in over 600-volt systems provide maintenance, monitoring, and servicing of the system.

2.15.1.3 Overcurrent Protection.

Feeders shall be protected against overcurrent in accordance with the provisions of Part 2.40.1. Where a feeder supplies continuous loads or any combination of continuous and noncontinuous loads, the rating of the overcurrent device shall not be less than the noncontinuous load plus 125 percent of the continuous load.

Exception No. 1: Where the assembly, including the overcurrent devices protecting the feeder(s), is listed for operation at 100 percent of its rating, the ampere rating of the overcurrent device shall be permitted to be not less than the sum of the continuous load plus the noncontinuous load.

Exception No. 2: Overcurrent protection for feeders over 600 volts, nominal, shall comply with Part 2.40.11.

2.15.1.4 Feeders with Common Neutral.

(a) Feeders with Common Neutral.

Two or three sets of 3-wire feeders or two sets of 4-wire or 5-wire feeders shall be permitted to utilize a common neutral.

(b) In Metal Raceway or Enclosure.

Where installed in a metal raceway or other metal enclosure, all conductors of all feeders using a common neutral shall be enclosed within the same raceway or other enclosure as required in 3.0.1.20.

2.15.1.5 Diagrams of Feeders.

If required by the authority having jurisdiction, a diagram showing feeder details shall be provided prior to the installation of the feeders. Such a diagram shall show the area in square feet of the building or other structure supplied by each feeder, the total calculated load before applying demand factors, the demand factors used, the calculated load after applying demand factors, and the size and type of conductors to be used.

2.15.1.6 Feeder Conductor Grounding Means.

Where a feeder supplies branch circuits in which equipment grounding conductors are required, the feeder shall include or provide a grounding means, in accordance with the provisions of 2.50.7.5, to which the equipment grounding conductors of the branch circuits shall be connected.

2.15.1.7 Ungrounded Conductors Tapped from Grounded Systems.

Two-wire dc circuits and ac circuits of two or more ungrounded conductors shall be permitted to be tapped from the ungrounded conductors of circuits having a grounded neutral conductor. Switching devices in each tapped circuit shall have a pole in each ungrounded conductor.

2.15.1.9 Ground-Fault Circuit-Interrupter Protection for Personnel.

Feeders supplying 15- and 20-ampere receptacle branch circuits shall be permitted to be protected by a ground-fault circuit interrupter in lieu of the provisions for such interrupters as specified in 2.10.1.8 and 5.90.1.6(a).

2.15.1.10 Ground-Fault Protection of Equipment.

Each feeder disconnect rated 1000 amperes or more and installed on solidly grounded wye electrical systems of more than 150 volts to ground, but not exceeding 600 volts phase-to-phase, shall be provided with ground-fault protection of equipment in accordance with the provisions of 2.30.7.6.

FPN: For buildings that contain healthcare occupancies, see the requirements of 5.17.2.8.

Exception No. 1: The provisions of this section shall not apply to a disconnecting means for a continuous industrial process where a nonorderly shutdown will introduce additional or increased hazards.

Exception No. 2: The provisions of this section shall not apply to fire pumps.

Exception No. 3: The provisions of this section shall not apply if ground-fault protection of equipment is provided on the supply side of the feeder.

2.15.1.11 Circuits Derived from Autotransformers.

Feeders shall not be derived from autotransformers unless the system supplied has a grounded conductor that is electrically connected to a grounded conductor of the system supplying the autotransformer.

Exception No. 1: An autotransformer shall be permitted without the connection to a grounded conductor where transforming from a nominal 208 volts to a nominal 240-volt supply or similarly from 240 volts to 208 volts.

Exception No. 2: In industrial occupancies, where conditions of maintenance and supervision ensure that only licensed electrical practitioner or non licensed electrical practitioner under the supervision of a licensed electrical practitioner service the installation, autotransformers shall be permitted to supply nominal 600-volt loads from nominal 480-volt systems, and 480-volt loads from nominal 600-volt systems, without the connection to a similar grounded conductor.

2.15.1.12 Identification for Feeders.

(a) Grounded Conductor.

The grounded conductor of a feeder shall be identified in accordance with 2.0.1.6.

(b) Equipment Grounding Conductor.

The equipment grounding conductor shall be identified in accordance with 2.50.6.10.

(c) Ungrounded Conductors.

Where the premises wiring system has feeders supplied from more than one nominal voltage system, each ungrounded conductor of a feeder, where accessible, shall be identified by system. The means of identification shall be permitted to be by separate color coding, marking tape, tagging, or other approved means and shall be permanently posted at each feeder panelboard or similar feeder distribution equipment.


Other Pages in this Category: Chapter 2. Wiring and Protection

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