FREE Journeyman Electrician’s Overcurrent Protection Questions and Answers

Question 1

According to NEC 240.4(D), what is the maximum standard overcurrent protective device (OCPD) rating for 10 AWG copper conductors that are not part of a multi-outlet branch circuit supplying receptacles?

Accepted Answer

30A

Answer

20A

Answer

25A

Answer

40A

Question 2

An electrician is installing a feeder tap that is 15 feet long. The feeder is protected by a 200A circuit breaker. What is the minimum required ampacity for these tap conductors?

Accepted Answer

67A

Answer

20A

Answer

100A

Answer

200A

Question 3

Which of the following locations is explicitly prohibited for the installation of overcurrent devices, according to NEC 240.24?

Accepted Answer

In the bathrooms of dwelling units

Answer

In a readily accessible basement

Answer

Above the ceiling in a commercial kitchen

Answer

Within a locked electrical room

Question 4

When is it permissible to use the next higher standard rating of an overcurrent protective device if the conductor's ampacity does not correspond to a standard size OCPD?

Accepted Answer

When the OCPD is rated 800A or less and other specific conditions are met

Answer

Only when the OCPD is rated 1000A or less

Answer

When the circuit supplies a single motor

Answer

It is never permissible to use the next higher standard rating

Question 5

A 480V to 208/120V, three-phase transformer has a primary full-load current of 60A and a secondary full-load current of 167A. If both primary and secondary protection is provided, what is the maximum standard size overcurrent device permitted on the primary side?

Accepted Answer

150A

Answer

60A

Answer

125A

Answer

70A

Question 6

For a continuous-duty motor with a nameplate full-load ampere (FLA) rating of 40A, a service factor of 1.15, and separate overload protection, what is the maximum rating for the overload device?

Accepted Answer

50A

Answer

40A

Answer

46A

Answer

60A