Packet 2

According to Article 220, Part III, the total dryer load on a service (or feeder) load of a multifamily occupancy may be calculated at ___ of the ungrounded conductor volt ampere neutral load

70% (220.61(B))

What is the calculated load for the general lighting load of a 24,000-square-foot one family dwelling?

72,000 (24,000 x 3)

Determine the minimum size of copper grounding electrode conductor for a 120/208 volt three phase service consisting of three 250 THW aluminum conductors paralleled per phase. The grounding electrode is building steel

750 Alum 1/0 Copper (3 x 250 Table 250.66)

The small appliance branch circuits required in a dwelling unit are calculated at ___

1,500 VA (220.52(A))

A department store has 120 feet of show window lighting operating of 120 volt circuit of a 120/208 volt system. Calculate the number of 120 volt, 20 ampere branch circuits needed for the show window lighting. Calculate the number of circuits to the larger whole number

13 circuits (show windows = continuous load) (200VA per ft x 120 ft = 24,000A / 120V = 200A) (200A x 1.25 = 250 = continuous load) (250A / 20 = 12.5 round up to 13)

What is the minimum number of 120 volt 20 ampere lighting branch circuits needed for a 1,800 square foot dwelling unit?

145 (1,800 x 3 = 5400 / 120 = 45)

Using an ampere load of 165 amperes, determine the minimum size 120/240 volt, single phase 3 wire service.

175 Breaker (1/0 copper or 3/0 aluminum) (Table 310.12)

The customer has decided to use the minimum size service. Using type THWN copper for the service conductors, determine the proper conductor size for a new 175 ampere dwelling unit single phase service

2/0 (Table 310.12)

Calculate the line and neutral lighting feeder demand for a 16,000 square foot dwelling unit, including small-appliance and laundry loads

20,325 (16,000 x 3 = 48,000 = Lighting load = 220.14(J)) (Laundry load = 1,500VA = 220.52(B)) (Small Appliance = 1,500 x 2 = 3,000 = 210.11(C)(1)) (Total = 52,500 - 3,000 of load at 100% = 49,500 T220.42) (49,500 x .35 for demand factor = 17,325) (17,325 + 3000 = 20,325 for neutral lighting feeder demand)

A department store has 120 feet of show window lighting operating on 120 volt circuit of a 120/208 volt system. Calculate the feeder demand in volt ampere for the show window lighting

24,000A (200VA per foot = 220.43)

Determine the minimum burial depth for Type USE, direct buried cables, which operate at 13.8kV. The direct buried cables are installed on commercial property not subject to vehicular traffic or concrete protection or encasement is not provided

30in (300.5)

An appliance store has 32 feet of multioutlet assembly. Calculate the volt ampere load when all the outlets are to be used at the same time.

5,760VA (32 x 180 = 5760 = 220.14(J))

A multifamily complex has 30 units with a 120/240 volt, six kilowatt dryer in each unit. What is the dryer load feeder demand for the ungrounded (or line) conductors of this complex? Round your answer to the nearest whole number

56,700VA (Over 5kw use nameplate load = # of dryers x 6kw) (30 x 6,000 = 18,000VA) (35-(.5 x (#of dryers - 23) T220.54 = demand factor) (35-3.5 = 31.5 x 18,000)

Each unit of a 12 unit multifamily dwelling is 2,000 square feet and supplied by a 120/240 volt, 3 wire system. Calculate the lighting load for each unit. Round your answer to the nearest whole number

6,000 (2,000 x 3)

How many 120 volt, 15 ampere lighting circuits are required for a dwelling unit with a calculated lighting load of 16,000 VA?

9 circuits (120 x 15 = 1,800) (16,00/1,800 = 8.8 round up to 9)

Using the total ampere load shown for each feeder, determine the appropriate THWN copper wire size based upon three parallel conductors per phase A) 958A B) 858A C) 758A D) 558A

A = 400 B = 350 C = 250 D = 3/0 (T310.16 for wire size) (All values divided by 3 before using table)

On a 4 wire delta connected service where the midpoint of one phase winding is grounding, the service conductor having the higher phase voltage to the ground shall be durable and permanently marked by an outer finish which is ___ in color, or by other effective means at which termination or junction point

Orange (110.15 or 230.56)

Which of the following wiring methods is NOT permitted for service entrance conductors rated over 600 volts, nominal when installed above ground?

Type AC cable (230.202(B) or 300.37)

The plans for a one family dwelling show that a 5 horse power, 240 volt single phase air conditioning unit and five kilowatt fixed electric space heater are to be installed using the same feeder circuit. Calculate each load and determine which single load will be used for the feeder demand. (Hint: The code refers to these loads as non-coincidental loads)

What is the air conditioning load? 28A (T430.248(AC motor load) 5hp 240 = 28A) What is the heating load? 5kw (220.51 = use 100% of load) What is the feeder demand for the noncoincidental loads? 6,720 VA (240V x 28A = 6720VA 220.60 = Larger = AC)

The feeder demand (line) load for a 5.5 kilowatt, 120/240 volt electric dryer in a dwelling unit is 5,500VA. What is the feeder (neutral) demand load in volt amperes for this electric dryer?

3,850 (5500 x .7 = 3,850 (220.61(B))