NJATC Load Calculations 2

Question 1

Per NEC 220.44, what demand factor may be applied to receptacle loads in office buildings that exceed 10,000 VA?

Accepted Answer

50%

Answer

NEC 220.44 permits a 50% demand factor for receptacle loads in excess of 10,000 VA in commercial occupancies such as office buildings.

Question 2

What is the required calculated load per linear foot of show window lighting per NEC 220.14(G)?

Accepted Answer

200 VA

Answer

NEC 220.14(G) requires 200 VA per linear foot of show window when calculating lighting loads for retail display windows.

Question 3

At what percentage of the continuous load must branch circuit conductors and overcurrent devices be rated per NEC 210.20(A)?

Accepted Answer

125%

Answer

NEC 210.20(A) requires branch circuit conductors and OCPDs to be rated at not less than 125% of the continuous load.

Question 4

Which formula correctly calculates true power (watts) in a three-phase circuit?

Accepted Answer

P = V × I × 1.732 × PF

Answer

Three-phase true power equals line voltage × line current × √3 (1.732) × power factor.

Question 5

What simplified NEC calculation method can be used for dwelling unit service sizing as an alternative to the standard method?

Accepted Answer

Optional Calculation per NEC 220.82

Answer

NEC 220.82 provides an Optional Calculation that simplifies residential service sizing using a general load per square foot plus specific appliance loads.

NJATC - National Joint Apprenticeship and Training Committee Practice Test

NJATC - National Joint Apprenticeship and Training Committee Practice Test

NJATC Load Calculations 2