Load Calculations & Branch Circuits Flashcards

Under the optional calculation method (NEC 220.82), what demand factor applies to the portion of the load over 10 kVA?

Answer: 40%

The optional method takes the first 10 kVA at 100% and the remainder at 40%.

In the optional method, the general lighting and small-appliance loads are combined with other loads and the first 10 kVA is taken at what percent?

Answer: 100%

The first 10 kVA of the combined general loads is taken at 100% in the optional calculation.

Using the optional method, which load is taken at the larger of 100% of A/C or 65% of central electric heating?

Answer: Heating/cooling

NEC 220.82(C) selects the largest among several heating/cooling scenarios, including 100% A/C or 65% of central heat.

What is the maximum number of 120-volt general-use receptacles considered acceptable on a 20-ampere residential circuit (no fixed limit, but rule of thumb)?

Answer: No NEC limit for dwellings

The NEC sets no numerical receptacle limit on general-purpose branch circuits in dwellings.

For non-dwelling occupancies, each general-use receptacle outlet is calculated at what VA per NEC 220.14(I)?

Answer: 180 VA

NEC 220.14(I) assigns 180 VA per single or multiple receptacle on one strap in non-dwelling occupancies.

A 1.5-ton residential A/C draws 24 A at 240 V. What VA is this for the optional calc?

Answer: 5760 VA

240 V x 24 A = 5760 VA.

Under the optional method, a household range nameplate of 12 kW is included at what value?

Answer: Nameplate 12 kW

The optional calculation uses the nameplate rating of appliances, so the full 12 kW is used in the combined load.