Branch-circuit-4.pptx

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1. Branch circuit

2. Wire Ampacity and Size Maximum loading for any branch circuit is 80% of rating of circuit for ampacity of wire for any load If circuit is loaded up to ampacity and distance to load is around 100 feet, then voltage drop will govern and will require larger wire size.

3. Wire Ampacity and Size

4. Circuit Breaker Size Maximum loading of any circuit breaker is 80% of rating for non-motor loads with exceptions as noted below. Breaker cannot be larger than ampacity of wire, except for motors and a few other loads.

5. Circuit Breaker Size

6. wire Size

7. Circuiting Guidelines (NEC) Sufficient circuitry to supply residential load of 30 watts per square meter in buildings excluding porches, garages and basements The requirement of 30 watts per square meter is up to 80 sq.m . for a 20 amperes circuit (2,400 watts) or 60 sq.m . for 15 amperes circuit (1,800 watts)

8. The load should ne exceed 1,600 watts for 20 amperes circuit and 1,200 watts for a 15 amperes circuit. Observe a minimum load of 1,200 watts on a 15 ampere circuit with a maximum area of 40 square meters. A maximum load of 1,600 watts on a 20 amperes circuit with a maximum area of 53 square meters Circuiting Guidelines (NEC)

9. A minimum of 20 amperes appliance branch circuit to feed all small appliance outlets in the kitchen, pantry, dining and family room The general purpose branch circuit shall be rated at 20 amperes circuit, wired with no. 12 AWG as minimum size of conductors required for all convenience outlet Circuiting Guidelines (NEC)

10. Circuit load on a 15 ampere circuit shall be limited to values given below Branch Circuit Capacity – Electric Heater Circuiting Guidelines (NEC) Circuit Breaker size Maximum Wattage 120 Volts Supply 240 volts Supply 15 amps 1440 2880 20 amps 1920 3840 30 amps 2880 5760

11. Branch Circuit Requirements   15 amps 20 amps 30 amps 40 amps 50 amps Maximum size of conductors # 14 # 12 # 10 # 8 # 6 Maximum size taps 14 14 14 12 12 Over current device rating 15 amps 20 amps 30 amps 40 amps 50 amps Lamp Holders permitted Any type Any type H-Duty H-Duty H-duty Receptacle rating permitted 15 amps 15-20 amps 30 amps 40-50 amps 50 amps Maximum Load 15 amps 20 amps 30 amps 40 amps 50 amps

12. Plug outlets or convenience outlet shall be counted in computing the load if it is not included in the load for general lighting circuit.  For 15 amps circuit = 9/1.5 = 6 outlets  For 20 amps circuit = 12/1.5 = 8 outlets  Convenience receptacles should be planned properly so that in case of failure by any one of the circuitry, the entire area will not be deprive of power supply. Each area should be provided alternately with different circuits. Circuiting Guidelines (NEC)

13. All kitchen outlets should be fed from at least two of convenience receptacles. Certain outlets in the room should be designed as appliance outlet like; All kitchen receptacles Dining room receptacles One in the living room Circuiting Guidelines (NEC)

14. At least one 20 amps circuit supplies the laundry outlets Provide a separate circuit for an air conditioning unit Lighting and receptacles should not be combined in a single circuit Avoid connecting all building lights on a single circuit Circuiting Guidelines (NEC)

15. Lighting and receptacles should be supplied with current from at least two circuits so that, if a single line is out, the entire area in not deprived of power Do not allow combination switch and receptacle outlets Provide at least 1 receptacle in the bathroom, and outside the house with GFCI type. Circuiting Guidelines (NEC)

16. Provide switch control for closet lights. Convenience outlet must be limited to 6 C.O on a 15 ampere circuit and 8 C.O on a 20 amperes circuit At least one 20 Amperes circuit supply shall be installed to the laundry outlets C.O shall be laid out in such a manner that no point on a wall is more than 2 meters from an outlet with GFCI type used. Circuiting Guidelines (NEC)

17. Other guidelines

18. Spaces About Electrical Equipment – Entrance to and Egress from Working Space – Personnel Doors Dedicated equipment space shall be provided for switchboards, switchgear, panel boards, and motor control centers installed in outdoor locations. The space shall be equal to the width and depth of the equipment and extend from grade to a height of 6 ft above the equipment .

19. What are the working space and dedicated equipment space requirements for outdoor electrical equipment? 3-4 ft deep, depending on the voltage and other conditions; the greater of 30 in. or the width of the equipment; and the greater of 6½ ft or the height of the equipment

20. Neutral Conductors – Multiple Circuits Significance Neutral conductors are generally not protected by overcurrent devices . It is necessary to be able to correctly identify circuit conductor pairs (grounded and ungrounded conductors of the same circuit) when splicing and terminating conductors to prevent overloading and mis-wiring.

21. Is there a neutral conductor in a 2-wire DC circuit (positive and negative polarity) that is not “earthed” at any point No, regardless of whether the circuit has either polarity connected to earth. A conductor connected to earth is a grounded conductor. A 3-wire, DC system contains a neutral point (at its mid-point).

22. Ground-Fault Circuit-Interrupter Protection for Personnel – Dwelling Units – Bathtubs or shower stalls In dwelling units, all 125-220 volt, single-phase, 15- and 20-ampere receptacle outlets installed within 6ft of the outside edge of a bathtub or shower stall shall be GFCI protected.

23. Ground-Fault Circuit-Interrupter Protection for Personnel – Dwelling Units – Laundry areas All 125-240 volt, single-phase, 15- and 20-ampere receptacle outlets installed in dwelling unit laundry rooms or areas shall be GFCI protected.

24. Ground-Fault Circuit-Interrupter Protection for Personnel – Other Than Dwelling Units All 125-250 volt, single-phase, 15- and 20-ampere receptacles installed in nondwelling garages, service bays, and similar areas shall have GFCI protection for personnel. Vehicle showrooms and exhibition halls are exempt from the GFCI requirement.

25. Ground-Fault Circuit-Interrupter Protection for Personnel – Kitchen Dishwasher Branch Circuit Dishwashers in dwelling units shall be GFCI protected.

26. The requirement for AFCI protection for 120-250 volt, single phase, 15- and 20-ampere branch circuits in dwelling units has been expanded to include all such circuits in kitchens and laundry areas. The only branch circuits that are exempt from AFCI protection: bathrooms, garages, outdoors, and basements Arc Fault Circuit-Interrupter (AFCI) Protection – Dwelling Units

27. Arc-Fault Circuit-Interrupter Protection – Branch Circuit Extensions or Modifications — Dwelling Units AFCI requirements are not applicable to dwelling unit branch circuit extensions, where the circuit extension is not more than 6′ in length and no additional outlets or devices are added to the existing branch circuit.

28. Arc Fault Circuit-Interrupter (AFCI) Protection – Dwelling Units

29. Arc Fault Circuit-Interrupter (AFCI) Protection – Dwelling Units