Chapter 12, Problem 24P

Fill in the chart and answer questions Answer problems 10, 11, and 12 using the following information:An addition is being planned to a school building. You have been asked to determine theload that will be added to the panelboard that will serve this addition.The addition will be a building 80 ft 3 50 ft. It will consist of four classrooms, every40 ft 3 20 ft and a corridor that is 10-ft wide The following loads will be installed:Each classroom:12 fluorescent luminaires, 2 ft 3 4 ft @ 85 VA each20 duplex receptaclesAC unit, 208-volt, 1-phase @ 5000 VACorridor:5 fluorescent luminaires, 1 ft 3 8 ft @ 85 VA each8 duplex receptaclesExterior:4 wall-mounted luminaires @ 125 VA each4 duplex receptacles 10. The calculated load is__________ VA.11. The connected load is__________ VA.12. The neutral load is_____________ VA.

A 1200-ampere service was installed, consisting of three sets of 600 kcmil THHN/THWN copper conductors per phase. The electrical contractor was careful to cut theconductors the same length. When the utility crew made up the connections at theservice heads, they cut the conductors to different lengths to make their connectionssimpler. The actual lengths of the service-entrance conductors in a given phase ended up being20 ft (6.1 m), 22 ft (6.7 m), and 24 ft (7.3 m). The maximum ampacity of a 600-kcmilTHHN/THWN copper conductor is 420 amperes using the 75°C column of Table310.16. This is more than adequate for the calculated 1200 amperes when three conductors are run in parallel. Determine how the load of 1200 amperes would divide in each of the three paralleledconductors in a phase.

Determine the conductor sizes for a feeder to a panelboard. It is a 120/240-volt,single-phase system. The OCPD has a rating of 100 amperes. The calculated load is15,600 VA. All the loads are 120 volts.