Grounding and Bonding, Level I - 2023 Lesson 5: Requirements for Services and Grounded Conductors

The ? is/are defined as the conductors and equipment for connecting the serving utility to the wiring system of the premises served.

A. service

Where a system is grounded, the service must be supplied with a(n) ? conductor.

C. Grounded

What is the minimum-size aluminum or copper-clad aluminum main bonding jumper (wire-type) for a service if the largest ungrounded service conductor is 500 kcmil copper?

D. 3/0 AWG

The grounded conductor of a service must always be a neutral conductor.

False

Where the utility transformer supplying a service is located outside the building, a grounding connection is not required to be made outside a building or structure served by a grounded electrical service.

False

A grounding electrode connection is required to be made at a(n) ? location anywhere from the load end of the overhead service conductors, service drop, underground service conductors, or service lateral up to and including the terminal or bus to which the grounded conductor is connected in the service disconnecting means.

A. accessible

A meter socket enclosure sealed by the utility makes the enclosure inaccessible, by definition.

False

Which of the following is not one of the four conductors in the grounding and bonding scheme for a service supplied by a grounded system?

E. System bonding jumper

Where a service is supplied by an ungrounded system, the grounded conductor is required to be routed to the service disconnecting means enclosure and bonded to it.

False

Where a service is supplied by a grounded system, the grounded conductor is required to be routed to the service disconnecting means enclosure and bonded to it.

True

The grounded conductor is required to be routed to the service equipment along with its associated ungrounded service conductors.

False

The main bonding jumper in a service disconnecting means enclosure can be in which of the following forms?

D. Any of the above

If a service disconnecting means is made up of six disconnects in separate enclosures grouped in the same location, how many main bonding jumpers will be required for the service?

D. 6

Where the service disconnecting means is made up of two to six disconnects that are compartmentalized in a single listed service equipment assembly, how many main bonding jumpers are required within the listed assembly?

A. 1

If a main bonding jumper is a wire type, what NEC table is used to size it?

C. Table 250.102(C)(1)

The grounded neutral conductor serves which two purposes for a grounded service?

I. Carries the maximum load of the ungrounded conductors supplied

II. Carries the maximum unbalanced return neutral load

III. Connects the system directly to earth

IV. Provides a conductive path to the grounding electrode system

V. Serves as an effective ground-fault current path in ground-fault events

C. II. and V.

If a main bonding jumper is a screw, the screw is required to be identified using the color green.

True

The ? is a conductor connected to the neutral point of a system that is intended to carry current under normal conditions.

D. neutral conductor

For a grounded service, the ? is the intentionally constructed, low-impedance, effective ground-fault current path connecting to the electrical supply source, and is addressed in 250.4(A)(5).

B. grounded conductor

If the ungrounded service conductors for a service are 600 kcmil copper, what is the minimum size required for the grounded conductor supplying the same service?

C. 1/0 AWG

If a service is supplied from a corner-grounded delta system and the ungrounded conductors are sized at 750 kcmil copper, what is the minimum size required for the grounded conductor?

D. 750 kcmil copper

Where a grounded service is supplied using two 500-kcmil copper conductors in parallel (in two separate raceways) for each ungrounded service conductor, what is the minimum size required for the grounded conductor in each raceway supplying the service?

C. 1/0AWG

Which of the following characteristics are required for ungrounded conductors installed in parallel?

I. Must be not smaller than 1/0 AWG (generally)

II. Must be the same color

III. Must be the same conductor material

IV. Must be the same insulation type

V. Must be the same length

VI. Must be the same size

VII. Must be terminated in the same manner

B. I., III., IV., V., VI., and VII.

Grounding connections to the grounded conductor are generally not permitted on the load side of the service equipment enclosure.

True

The insulation of a grounded conductor (often the neutral) that is 4 AWG or larger is required to be identified by which of the following methods?

E. Any of the above

The service disconnecting means used for a grounded supply system is required to be listed as suitable for use as service equipment.

True

Service equipment that is listed as suitable for use only as service equipment always includes a main bonding jumper.

False

The NEC requires that a(n) ? be provided in the grounded conductor for service equipment.

B. disconnecting means

If a service switchboard is supplied from an ungrounded 240-volt system, which of the following markings are required on the switchboard?

B. Caution: Ungrounded System Operating 240 Volts Between Conductors

The NEC generally requires all metal enclosures and raceways for service conductors to be grounded except for metal components such as metal elbows in a run of nonmetallic service raceway that are isolated from contact by persons by not less than ? of cover to any part of the elbow.

B. 18"

Ground detectors are required to be installed on services supplied by ungrounded systems, and the ground detection sensing equipment must be connected as close as practicable to the service or source.

True

If the size of the largest ungrounded service conductor for a service is 3,600 kcmil (six 600 kcmil conductors in parallel per phase), what is the minimum-size copper wire-type main bonding jumper required?

D. 500 kcmil copper

Referring to the drawing, drag and drop the six grounding and bonding components that correspond to the correct location in this service installation.

Starting From Top Box Going Down On Picture:

Supply-side bonding jumper

Grounded conductor

Main bonding jumper

Grounding electrode conductor

Grounding electrode

Equipment grounding conductor

Referring to the drawing, what is the minimum size required for a copper wire-type main bonding jumper for this service?

A. 2 AWG

What is the minimum size required for a copper grounded conductor of a 3-phase, 3-wire, corner-grounded delta system if the ungrounded phase conductors are sized at 500 kcmil copper?

D. 500 kcmil

The sizing of grounding electrode conductors for alternating current (AC) systems is generally addressed in 250.66, and the sizing of equipment grounding conductors is generally addressed in 250.122. The sizing of grounded conductors, such as those covered by 250.24(D) where sized for a single raceway or cable, are generally addressed in which of the following?

C. 250.102

Where the utility transformer supplying the service is located outside the building or structure served, at least one additional grounding connection shall be made from the grounded service conductor to a grounding electrode at which of the following locations?

D. Either a. or b.

If the largest ungrounded derived phase conductor for an AC generator is 750 kcmil copper, what is the minimum size required for a wire-type system bonding jumper?

B. 2/0 AWG copper

The minimum size grounding electrode conductor for an energy storage system that has a 500-kcmil copper ungrounded supply-side derived phase conductor(s) must not be less than ? . The grounding electrode to be used is an underground metal water pipe electrode.

C. 1/0 AWG

Which of the following materials is/are permitted for use as main and system bonding jumpers?

D. All of the above