Electricity level 2, section 9

Where a main bonding jumper is required by the NEC, the jumper cannot be less than what percentage of the area of the largest phase conductor?

12.5%

A transformer-supplied system operating at less than 50v must be grounded if the supply voltage to the transformer exceeds

150V

Rod, pipe, and plate electrodes must have a resistance to ground of at least

25 ohms or less

The minimum diameter of galvanized pipe allowed allowed for a grounding electrode is

3/4"

The minimum length allowed for driven ground rods under normal conditions is

8'

Which type of system is required to be grounded?

Ac systems over 1kV that supply mobile or portable equipment

When a ground rod is installed, the top of the rod must be positioned

Below permanent moisture level is practicable

A ground fault is described as an unintentional

Electrically conducting connection between an ungrounded conductor of an electrical circuit and the normally non-current-carrying conductors

Which of the following is true of the neutral in a grounded system?

It provides a low-impedance return path for the flow of fault current to the source.

The requirements for grounding of services are located in

NEC sections 250.24(A), (B), (C), and (D)

If single-gang, Nail-on, nonmetallic boxes are used with NM cable, which of the following is true?

No connection to the box is required.

Which of the following must have at least 2 square feet of surface area exposed to the surrounding earth?

Plate electrode

Which of the following is true when installing grounding at more than one building?

The grounded circuit conductor and the equipment grounding conductor must both be extended to the second building

Which of the following is an NEC requirement for grounding and bonding?

The path to ground from circuits, equipment, and metal enclosures shall be continuous.

To be effective, a grounding system must limit the voltage on the electrical system and protect it from

Voltage surges

A short circuit is a conducting connection between

any of the conductors of an electrical system

The continuity between service equipment and enclosures is maintained by

bonding

The fall-of-potential method is used to measure

earth resistance

The bonding jumper for multiple disconnecting means is located

on the supply side of the service disconnect

A separately derived system is a premises wiring system that is

powered from a source other than a service

System grounding relates to the

service-entrance equipment

The size of the equipment grounding conductor (EGC) is determined by the

size of the over current device protecting the system

In a separately derived system, the equipment bonding jumper connects the

system housing to the neutral bus bar

A ground test utilizing an auxiliary current electrode and an auxiliary potential electrode is known as the

three-point test

The maximum value of a short circuit current from line-to-neutral (grounded)

will vary depending on the distance from the source to the fault