FREE Licensed Electrical Contractor Services, Feeders, and Branch Circuits Questions and Answers

Question 1

According to NEC 215.2(A)(1), what is the minimum allowable ampacity for feeder conductors supplying a combination of continuous and noncontinuous loads?

Accepted Answer

125% of the continuous load plus 100% of the noncontinuous load.

Answer

100% of the continuous load plus 100% of the noncontinuous load.

Answer

125% of the continuous load plus 125% of the noncontinuous load.

Answer

100% of the continuous load plus 125% of the noncontinuous load.

Question 2

A contractor is installing a new service and plans to use multiple disconnects. Per NEC 230.71 (2020 and later editions), which of the following arrangements for two to six service disconnects is permissible?

Accepted Answer

Two separate enclosures, each containing a main service disconnecting means.

Answer

Six circuit breakers installed within a single panelboard enclosure without a main breaker.

Answer

A panelboard with a main service disconnect and another five disconnects in a separate trough.

Answer

Three disconnects in one enclosure and three in another enclosure on the opposite side of the building.

Question 3

A multi-family dwelling has five individual apartment units, each with a 14 kW electric range. What is the calculated demand load for these cooking appliances on the service-entrance conductors according to NEC Table 220.55?

Accepted Answer

23.1 kW

Answer

70 kW

Answer

22 kW

Answer

20 kW

Question 4

Which of the following is a mandatory requirement for a multi-wire branch circuit (MWBC) according to NEC Article 210?

Accepted Answer

A means must be provided to simultaneously disconnect all ungrounded conductors at their origin.

Answer

The neutral conductor must be one size larger than the ungrounded conductors.

Answer

It can only supply line-to-line loads.

Answer

All conductors of the circuit must be enclosed in a metallic raceway.

Question 5

An electrician needs to tap from a 200A feeder protected by a 200A circuit breaker to supply a 60A panelboard. The total length of the tap conductors will be 18 feet. According to the 25-foot tap rule in NEC 240.21(B)(2), what is the minimum required ampacity of the tap conductors?

Accepted Answer

67A

Answer

60A

Answer

20A

Answer

100A

Question 6

When is it required to establish a new grounding electrode system for a transformer installation?

Accepted Answer

When the transformer is classified as a separately derived system.

Answer

For all step-up transformer installations.

Answer

Only when the transformer is installed outdoors.

Answer

For all transformers exceeding 50 kVA.