FREE TN-LLE Service and Feeder Sizing Questions and Answers

Question 1

What is the minimum ampacity for feeder conductors supplying a continuous load of 90 amps and a noncontinuous load of 40 amps?

Accepted Answer

152.5A

Answer

130A

Answer

162.5A

Answer

175A

Question 2

Per NEC 230.71(B), what is the maximum number of service disconnects allowed to be grouped in a single location for each service?

Accepted Answer

Six

Answer

One

Answer

Two

Answer

Four

Question 3

According to NEC 230.70(A)(1), the service disconnecting means shall be installed at a readily accessible location:

Accepted Answer

Either outside or inside nearest the point of entrance

Answer

Inside a locked electrical room

Answer

Within 50 feet of the service point

Answer

In the attic space above the garage

Question 4

A 120/240V single-phase service for a dwelling unit has a calculated load of 95 amps. What is the minimum standard service size that can be installed according to NEC 230.79(C)?

Accepted Answer

100A

Answer

90A

Answer

95A

Answer

125A

Question 5

A feeder is installed to supply a subpanel in a detached garage. Which of the following is required for the feeder?

Accepted Answer

It must include an equipment grounding conductor.

Answer

It must be installed in rigid metal conduit only.

Answer

It must have a disconnect within sight of the main panel.

Answer

It must be protected by a GFCI breaker at the source.

Question 6

The ungrounded service-entrance conductors for a commercial building have a calculated load of 180A. What is the minimum standard size overcurrent device that can be used to protect this service?

Accepted Answer

200A

Answer

175A

Answer

180A

Answer

225A