Journeyman Electrician's Load Calculations Flashcards

A 2,000 sq ft dwelling has two small appliance circuits and one laundry circuit. What is the total general load before demand factors?

Answer: 10,500 VA

2,000 sq ft × 3 VA = 6,000 VA lighting, plus 2 × 1,500 VA = 3,000 VA small appliance, plus 1,500 VA laundry = 10,500 VA.

Using the NEC 220.82 optional calculation method for dwelling units, what percentage applies to all general loads above 10 kVA?

Answer: 40%

NEC 220.82(B) applies 100% to the first 10 kVA of general loads and 40% to all remaining general loads above that.

Per NEC Table 220.42, what demand factor applies to dwelling unit lighting loads that exceed 120,000 VA?

Answer: 25%

NEC Table 220.42 applies a 25% demand factor to the portion of dwelling unit lighting loads exceeding 120,000 VA.

A commercial space has 50 duplex receptacle outlets. Per NEC 220.14(I), what is the total calculated receptacle load?

Answer: 9,000 VA

Per NEC 220.14(I), each duplex receptacle counts as one outlet at 180 VA, so 50 × 180 VA = 9,000 VA.

Per NEC 220.54, what is the minimum demand load that must be used for a household electric clothes dryer when the nameplate rating is less than 5,000 watts?

Answer: 5,000 W

NEC 220.54 states the demand load for electric clothes dryers shall be 5,000 W or the nameplate rating, whichever is larger.

Per NEC Table 220.55, what is the maximum allowable demand load for a single 10 kW household electric range?

Answer: 8 kW

NEC Table 220.55, Column C allows 8 kW demand for a single range rated over 8¾ kW through 12 kW, which includes a 10 kW unit.

What is the calculated demand load for a dwelling unit's general lighting if the total connected lighting load is 9,000 VA?

Answer: 5,100 VA

Per NEC Table 220.42: first 3,000 VA × 100% = 3,000 VA, plus remaining 6,000 VA × 35% = 2,100 VA, totaling 5,100 VA.