BRANCH CIRCUITS 1 Ted Smitty Smith E Light

BRANCH CIRCUITS 1 © Ted “Smitty” Smith E Light Electric Services, Inc.

• • • Directions • The first several slides of this presentation are a review of calculations. Read them over and take some notes as they will help you on your journeyman’s exam as well as while doing this drill. Click the slide to advance to the next slide as you are ready. You will reach a slide which says “START”. This is the beginning of the timed portion of the drill. Click that slide and the questions slides will start running. Each slide will remain in place for 3 -5 minutes depending on the difficulty of the calculation. A sound will go off letting you that it has moved to the next slide. Attempt to answer the question. If you finish before the timer goes off, click the slide and it will go to the next question. If you do not finish, simply stop working that problem and start on the next. When you reach the end of the timed portion you will see a slide that says “STOP”. Click on that slide and each of the questions will reappear and this time you can click them to move to the next slide, which will have the answer. Please call me if you have any issues or questions and I will be happy to arrange a time for us to review.

Continuous and Non Continuous The definition of a continuous load is a load where the maximum current is expected to continue for 3 hours or more. Non Continuous • A non continuous load is a load that is not continuous.

Branch Circuit and Feeder Branch Circuit: The circuit conductors between the final overcurrent protective device and the outlets Feeder: The conductors from the service or transformer to the last overcurrent protective device

Key Articles • Branch Circuit Demands – Article 220 – Table 220. 12 for Lighting – 220. 14 for specific type loads • Article 210 for Branch Circuit Ratings – 210. 18 though 210. 25 • Branch Circuit Voltage Limitations – 210. 6 • GFCI Protection – 210. 8 • AFCI Protection – 210. 12 • Appliances – Article 422 • Electric Space Heating Equipment • -Article 424

Branch Circuit Ratings 210. 18 Branch circuit rating is based on the Overcurrent Protective Device Rating 210. 19 and 20 Branch circuits conductors must be sized based on 125% of the continuous loads and 100% of the non continuous loads 210. 20 Exception IF the OCPD is listed for operation at 100% of its rating, then the overcurrent device can be sized at 100% of all loads. Some Mins • Branch circuits supplying more than one receptacle for cord and plug loads shall have an ampacity equal to the branch circuit rating. • Branch circuits for ranges rated 8 ¾ k. W or greater shall have a minimum rating of 40 amperes.

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• A continuous load is a load where the maximum current is expected to continue for ______ or more. • A. 15 minutes • B. 1 hour • C. 2 hours • D. 3 hours

• D. 3 Hours • Article 100 • Definitions

• In general, branch circuit conductors serving continuous loads are required to have an allowable ampacity of at least _____ of the load(s) to be served. – A. 80% – B. 100% – C. 125% – D. 150%

• C 125% • 210. 19(A)(1)(a)

• A six story office building having an outside dimension of 100 feet by 150 will have a general lighting demand of _______. • A. 150 k. VA • B. 100 k. VA • C. 315 k. VA • D. 45 k. VA

• C. 315 k. VA T 220. 12 100 x 150=15, 000 x 6=90, 000 square feet 90, 000 x 3. 5=315, 000= 315 k. VA

Which of the following is not a standard sized overcurrent protective device? A.

• C. 1500 A • T 240. 6

• What is the minimum sized circuit breaker(s) required for a range cooking

• Power supply would need to be divided into two circuits of 240 V each. It would require (2) 35 A, two pole circuit breakers, one for each circuit. • T 220. 55 8000 W x 1. 85=14, 800 W of demand • 14, 800/240=61. 66 Amps • 422. 11(B) requires the ranges with over 60 A of demand be fed with two circuits and each circuit have an OCPD of not greater than 50 A.

• What is the demand for the 233 feet of 120 V, Track Lighting installed in a retail store if the track lighting will have fixtures installed every 36 inches and each fixture is 60 watts? – A. 117 k. W – B. 17. 55 k. W – C. 150 k. W – D. 17. 4 k. W

• B. 17. 55 k. W • 220. 43(B) • 233/2= 116. 5 • 150 watts per 2 feet or fraction. [ Any fraction] 117 2 foot sections • 117 x 150= 17, 550 watts • 17550= 17. 55 k. VA

• A 240 volt, single phase, 3600 watt electric water heater is to be installed in a residential garage? What is the maximum size circuit breaker which can be used for overcurrent protection for the water heater? – A. 15 A – B. 20 A – C. 30 A – D. 25 A

• D. 25 Amperes 422. 11(E)(3) 3600 W/240 V= 15 A 15 x 150%= 22. 5 Amperes

• The auxiliary equipment for electric discharge lights rated at 600 volts nominal which will be used for stadium lights and mounted poles shall be a minimum of _____ feet above the ground. –A. 10 feet –B. 15 feet –C. 22 feet –D. 18 feet

C. 22 feet 210. 6(D)

Receptacles located in a garage of a dwelling unit shall be supplied by a dedicated 120 volt, _____ ampere circuit with no other outlets. A. 10 A B. 15 A C. 30 A D. 20 A Copyright 2008 Ted "Smitty" Smith

• D. 20 A • 210. 11(C)(4)

• What is the minimum number of 20 ampere, 277 V branch circuits required to supply one hundred fluorescent fixtures if each fixture has a current rating of. 75 amperes? –A. 4 –B. 7 –C. 6 –D. 5

• D. 5 • 220. 18(D) 100 x 277 x. 75=20, 775 VA These will be continuous duty so 20, 775 x 1. 25= 25, 968. 75 VA / 277 V = 93. 75 A 93. 75 A /20 A= 4. 68 This will require a minimum of 5, 20 A circuits

What are the minimum number of 20 Ampere branch circuits required for a single family dwelling that has outside dimensions of 62 feet by 36 feet? A. 2 B. 3 C. 5 D. 7

• C. 5 • • • 210. 11(C) 2 small appliance branch circuits 1 laundry circuit 1 bathroom receptacle circuit 1 garage receptacle circuit

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