Philippine Electrical Code (PEC) standards

• Electrical design standards ensure safety for people and buildings.

Electrical Codes, Licenses, and Permits

• Electrical codes set minimum safety standards for electrical systems, covering manufacturing and installation.
• The main purpose of electrical codes is to ensure the safety of people and buildings.
• The Philippines uses the Philippine Electrical Code (PEC), which is nationally enforced.
• The National Electrical Code (NEC) is a model code that local governments can adopt into law. It was established in 1987.
• The National Fire Protection Association (NFPA) became the sponsor of the NEC in 1911.

Purpose of the Philippine Electrical Code (PEC)

• To protect people and property from electrical hazards.
• To establish standards for electrical materials and workmanship.
• The PEC aims to ensure electrical designs are safe for end-users and property.
• Hazards often arise from overloaded wiring systems or non-compliance with the code.
• Consulting a licensed electrical practitioner (RME, REE, PEE) is recommended for electrical work with updated, renewed credentials.
• Lack of maintenance or improper wiring can lead to fire, electrocution, injury, or death.
• PEC serves as a design specification and instruction manual for licensed professionals.

Licensing and Permits

• Most municipalities require licenses for anyone installing electrical systems.
• Municipalities typically require permits before any electrical installations begin.
• Under RA 7920, also knows as the National Electrical Engineering Law, licensed practitioners must get electrical permits for buildings.
• Complete electrical plans need review and approval before any installation starts.
• Municipal electrical inspectors check wiring during scheduled visits before construction materials conceal it.

Electrical Construction Drawings

• These show the layout and design of electrical installations.
• A complete set of drawings and specifications is required to convey design information to contractors
• Construction drawings should include:
  • Complete plans and specifications for all electrical work
  • Labeling criteria for all electrical equipment.
  • Lighting floor plans with electrical circuits, conduit, and wiring sizes.
  • Power floor plans that indicating conduit and wiring sizes, equipment, and disconnect switches
  • Details on exit sign and egress lighting locations with power supply
  • Panel board schedules.
  • Lighting fixture schedules.
  • Symbol schedule and diagrams.

Review of Design Requirements

• The location plan guides electrical design engineers, inspectors, bidders, and other interested parties.
• The electrical layout resembles the architectural layout but includes details on:
  • Service drop/lateral
  • Service entrance
  • Service equipment
  • Feeders
  • Subfeeders
  • Load centers
  • Panelboards
  • Branch circuits
  • Occupancy nomenclature

Legends and Symbols

• These aid in understanding electrical plans, with recommended symbols shown in Appendix A of PEC Part 1.
• Local symbols can be used if they are easily understood in the area.

General Notes and Specifications

• These outline the nature of electrical service:
  • Number of phases
  • Number of wires
  • Voltage
  • Frequency
• Common electrical service types:
  • 230V, 60Hz, single phase, 2W for domestic use.
  • 120/240V (split-phase), 60Hz, single phase, 3W+1N for cities.
  • 230V/400V, 60Hz, three phase for commercial buildings.

Types of Wiring

• Cleat wiring is a rarely used temporary system.
• Casing and capping wiring involves cables in a wooden enclosure.
• Batten wiring
• Lead sheathed wiring
• Conduit wiring is divided into:
  • Surface wiring (exposed conduits)
  • Concealed conduit wiring (hidden conduits).
• Special equipment ratings and classifications must be indicated, including:
  • Hertz
  • Number of poles
  • KAIC rating

Grounding Methods

• System grounding protects against electric shock, lightning, and fires through building electrical system.
• Equipment grounding uses a bare or green-colored conductor, seen in appliances like refrigerators and washing machines.
• Electrical panels should be installed a minimum of 4 feet off the ground but no higher than 6 feet, with allowance for 90-degree door opening.

Height of Electrical Fixtures

• Switches- 48 inches
• Outlets - 12 inches

Schedule of Loads and Diagrams

• A load tabulation details branch circuits, load ratings, power sources, and wiring information.
• A single line or riser diagram indicates the interconnection, size, and rating of service components for short circuit current and voltage drop calculations.
• The Title Block contains:
  • Installation name and location
  • Owner’s name, signature, and address
  • Professional Electrical Engineer details (PRC license, PTR number, TIN)
  • Sheet contents, scale, and drawing number

Design Analysis Considerations

• This includes computation or selection of:
  • Wire and conduit sizes for circuits, feeders, and service entrance.
  • Overload protective device types, ratings, and trip settings.
  • Short circuit current and interrupting capacity of protection devices.
• Electrical design principles for single-story residential buildings share similarities with those for high-rise structures.
• The electrical design starts from architectural layouts and drawings.
• Preparations involve initial arrangements which help determine the number of drawing sets required to avoid overcrowding.

Design Example

• Considers a 100 sq. m single-family home with specific appliance and circuit details.
• Includes branch circuits, lighting, appliances, laundry, electric range, clothes dryer, and air conditioning units.

Computation of Loads for a Typical Residential Unit (Example)

• General Lighting and Convenience Receptacle (Branch Circuit No. 1)
  • For a 100 sq. m unit, the load is 3,300 volt-amperes, resulting in a current of 14.35 Amperes
  • Utilizes 2.00mm² copper THHN conductors in 15mm rigid PVC conduit with a one 20A branch circuit.
• Small Appliances Load (Branch Circuit Nos. 2-4)
  • Each 20A circuit is rated at 1,500 volt-amperes, totaling 6.52 amperes.
  • Employs 3.5mm² copper THHN conductors in 15mm rigid PVC conduit with three 20A circuits. Laundry Circuit (Branch Circuit No. 5)
  • Rated at 1,500 volt-amperes, drawing 6.52 amperes.
  • Uses 3.5mm² copper THHN conductors in 15mm rigid PVC conduit with a three 20A circuit.
• 10kW Electric Range Load (Branch Circuit No. 6)
  • With a maximum demand of 8kW, the load current is 34.78 amperes.
  • Requires 8.00mm² copper THHN conductors in 15mm rigid PVC conduit with one 50A circuit.
• 5kW Clothes Dryer Load (Branch Circuit No. 7)
  • The load is 5kW with 100% demand factor, totaling 21.73 amperes.
  • It is Wired with 5.50mm² copper THHN conductors in 15mm rigid PVC conduit.
• Air Conditioning Units
  • 3/4 HP Air-Conditioning Unit (Branch Circuits Nos. 8 and 9)
    • The wire ampacity is 8.63A (125% of the motor full load current).
    • 3.5mm², copper THHN conductors need to be used in 15mm diamater rigid PVC conduit.
    • The Rating of branch circuit protective device is 17.25A (250% x 6.9A).
    • Two (2) 20A small appliance branch circuit is needed.
• 1.5HP Air-Conditioning Unit (Branch Circuits No. 10)
  • The wire ampacity is 12.50A (125% of the motor full load current).
  • 5.5mm², copper THHN conductors need to be used in 15mm diamater rigid PVC conduit.
  • The Rating of branch circuit protective device is 25A (250% x 10A)
  • One (1) 30A small appliance branch circuit is needed.
• General Lighting and General Use Receptacle is 3300VA. 2-3.5 mm² THHN copper wire is needed for general lightings.
• Small appliance load is 4500VA. 2- 3.5 mm² THHN copper wire is needed for small appliance.
• Laundry circuit load is 1500VA. 2- 3.5 mm² THHN copper wire is needed for laundry circuit load.
• Clothes dryer is 5000VA. 2-5.5 mm² THHN copper wire for clothes dryer is needed.

Application of Demand Factors

• Considers factors for general loads, demand factors for other loads, and service entrance.
• Demand Factors: First 3,000 Volt-Amperes @ 100% is 3,000VA. Remainder @ 35% Factor is 3,955VA. Total computed load is 6,955VA.

Other Loads Computation

• Range load requires one 50A circuit breaker and mm² THHN copper wire.
• ¾HP ACU load requires two 20A circuits, each using 3.5mm² THHN.
• 1.5HP ACU load needs one 30A circuit, using 5.5mm² THHN.
• Total net computed load stands at 21,129 VA, with a 3000VA protection level.

Service Entrance Conductor

• The maximum current rating of the protective device should be determined using a non-time delay fuse: 101.87 Amperes.
• The maximum current rating of the protective device should be determined using an inverse-time circuit breaker: 96.87 Amperes.

Service Equipment Recommendations

• Use a 200A, 2PST, 250V safety switch with 125A renewable fuses.
• Alternately, use one 125AT, 2 pole, 240V, molded case circuit breaker.
• A Project requires:
  • Lighting Layout
  • Power Layout
  • Schedule of Loads
  • Riser Diagram
  • Branch Circuit Computations
  • Service Entrance Computations
  • General Notes
  • Specifications
  • Legends
  • Location

General Lighting Loads by Occupancy

• Armories and auditoriums: 11
• Banks: 39b
• Barber shops and beauty parlors: 33
• Churches: 11
• Clubs: 22
• Court rooms: 22
• Dwelling units": 33
• Garages - commercial (storage): 6
• Hospitals: 22
• Hotels and motels, including apartment houses without provision for cooking by tenants": 22
• Industrial commercial (loft) buildings: 22
• Lodge rooms: 17
• Office buildings: 39b
• Restaurants: 22
• Schools: 33
• Stores: 33
• Warehouses (storage): 3
• In any of the preceding occupancies except one-family dwellings and individual dwelling units of two-family and multifamily dwellings
• Assembly halls and auditoriums: 11
• Halls, corridors, closets, stairways: 6
• Storage spaces: 3

Lighting Load Demand Factors

• Dwelling units -First 3000 or less at: 100%
• Hotels and motels, including apartment houses without provision for cooking by tenants* -Remainder over 100,000 at: 30%

Maximum Number of Conductors in Trade Sizes of Conduit Tubing

• Conduit Trade Size values and and measurements for the following types:
  • TW
  • T
  • THW
  • RUH (14-30)
  • RUW (14-30)
  • FEPB (14-30)
  • RHW and RHH

Demand Factors and Loads for Household Electric Ranges, Wall-Mounted Ovens, Counter-Mounted Cooking Units, and Other Household Cooking Appliances over 1½ kW Rating

• Column A (Less than 3½ kW Rating)
• Column B (3½ kW to 8% kW Rating) Maximum Demand (kW) (See Notes)
• Column C (Not over 12 kW Rating)

Full-Load Currents in Amperes, Single-Phase Alternating-Current Motors

• Shows 115 Volts, 200 Volts, 208 Volts, 230 Volts and how much horsepower is needed for each voltage setting.

Standard Ampere Ratings.

• Describes the standard ampere ratings for (a) Fuses and Fixed-Trip Circuit Breakers.

2.20.3.13 Small Appliance and Laundry Loads - Dwelling Unit.

• Describes the appliance circuit load in detail.
• The purpose of (b) Small Appliances and laundry circuit load.

Dwelling Units Circuit Details

• Details the (1) Small-Appliance Branch Circuits, (2) Laundry Branch Circuits and (3) Bathroom Branch Circuits.

Maximum Rating or Setting of Motor Branch-Circuit Short-Circuit and Ground-Fault Protective Devices

• Table describes certain types of Percentage of Full-Load current that apply to the electrical system.

Single Motor-Compressor

• Describes different parameters and uses of a single motor compressor.

Voltage System

• Lists voltage systems
• Describes Color and Identification Marking Code
• Explains Grounded neutral and what color to mark lines. -120VAC -120/240 VAC -208/120VAC -480/277VAC
  • 240/120VAC
  • 480VAC