Licensed Electrical Contractor Branch Circuit Calculations 5

Question 1

A hotel room branch circuit supplies only receptacles. The NEC allows a demand factor for hotel receptacle loads above a certain threshold. What is the demand factor applied to hotel guest room receptacle loads exceeding the first 10 kVA?

Accepted Answer

50%

Answer

NEC Table 220.42 allows a 50% demand factor for hotel guest room receptacle loads above the first 10 kVA.

Question 2

What is the maximum rating of an individual branch circuit that can serve a single receptacle outlet per NEC 210.21(B)(1)?

Accepted Answer

The receptacle rating must equal the branch circuit rating

Answer

NEC 210.21(B)(1) states a single receptacle on an individual branch circuit must have an ampere rating equal to the branch circuit rating.

Question 3

A branch circuit in a school classroom is calculated at 3.5 VA per square foot for a 900 sq ft room. What is the total branch circuit load in VA?

Accepted Answer

3,150 VA

Answer

Total load = 3.5 VA/sq ft × 900 sq ft = 3,150 VA for the classroom branch circuit load.

Question 4

Which of the following best describes a multiwire branch circuit as defined in NEC Article 100?

Accepted Answer

A circuit with two or more ungrounded conductors sharing a common neutral, with voltage between ungrounded conductors

Answer

A multiwire branch circuit has two or more ungrounded conductors sharing a common neutral, with line-to-line voltage between the hot conductors.

Question 5

A 120/240V, 3-wire multiwire branch circuit must have its ungrounded conductors disconnected simultaneously per NEC 210.4(B). Which device accomplishes this?

Accepted Answer

A 2-pole breaker or handle-tied single-pole breakers

Answer

NEC 210.4(B) requires a means to simultaneously open all ungrounded conductors, accomplished by a 2-pole breaker or handle-tied single-pole breakers on opposite phases.

Licensed Electrical Contractor Practice Test

Licensed Electrical Contractor Practice Test

Licensed Electrical Contractor Branch Circuit Calculations 5