CDC 3E051A Vol.2 Unit 2

What number is the maximum ohmic reading for static grounds according to current Air Force directives?

A) 10
B) 1,000
C) 10,000
D) 100,000

An equipment ground is a grounding system that

A) Connects to earth all nonconcurrent carrying metal parts of an electrical wiring system.
B) Remove excess voltage from current carrying metallic objects
C) Drains off static electricity before a sparking potential is a reached.
D) Stabilizes voltage between two or more metallic objects.

What maximum ground resistance is the value for an electrical system with a voltage of 600 volts alternating current (VAC) or less?

A) 5 ohms
B) 25 ohms
C) 10 ohms
D) 1 ohms

During which season could you expect to measure the lowest ground reading?

A) Fall
B) Winter
C) Spring
D) Summer

Which location is the correct location for grounding a system neutral?

A) Source side of service entrance
B) Load side of service entrance and outlets
C) Load side of service entrance
D) Source side of service entrance and outlets

A system neutral conductor is likely grounded improperly (grounded on the load side of the service entrance disconnect), if the ohmic value is less than

A) 20K
B) 30K
C) 40K
D) 10K

At what intervals should a wye-connected distribution system neutral be grounded?

A) This system neutral is not grounded.
B) At a distance not to exceed 1 mile.
C) At a distance not to exceed 1/4 mile.
D) At a distance not to exceed 1/2 mile.

What recommended depth is the top of a ground rod driven for distribution pole grounding?

A) At ground level.
B) 2 feet below ground level.
C) Below ground level.
D) 1 foot above ground level.

The metal frame of a building can be used as a facility ground

A) only if the braces are separately bonded to the ground loop.
B) if the building is equipped with air terminals.
C) only when it is supported by insulated flanges.
D) if the frame is effectively grounded.

What are the requirements for a facility ground rod?

A) 4 feet long; copper-clad steel, solid copper, or stainless steel.
B) 8 feet long; copper-clad steel, solid copper, or stainless steel.
C) 4 feet long; copper-clad steel, solid copper, or galvanized steel.
D) 8 feet long; copper-clad steel, solid copper or galvanized steel.

Which is the maximum allowed resistance for an electrode used for communications network grounds?

A) 5 ohms
B) 10 ohms
C) 20 ohms
D) 25 ohms

Isolated ground (IG) receptacles are used in circuits feeding electronic devices to

A) minimize noise.
B) filter voltage spikes.
C) block high voltage generated from lightning strikes.
D) stabilize current draw.

In an isolated ground (IG) receptacle, the

A) IG must have its own lighting arrester.
B) grounding pin is purposely insulated from the outlet box.
C) IG must have its own driven ground rod.
D) IG will be bonded to other grounds in the immediate area.

What happens if a bare grounding wire touches the hot conductor terminal of a receptacle inside of a properly grounded outlet box?

A) The neutrals for the entire facility become hot conductors.
B) The outlet voltage is doubled.
C) The circuit breaker for that circuit trips.
D) Equipment plugged in the receptacle receives excessive current and overheats.

Physical failure of grounding systems usually occurs in which portion of the system?

A) In the service panel.
B) The ground electrode.
C) At the point where it attaches to the equipment.
D) Just above and below ground level.

In an interior wiring system with metallic conduit, through how many possible paths can return ground fault flow?

A) Zero
B) Two
C) One
D) Three

What test can you perform to ensure that the above grade components in a grounding system have a low resistance path to ground?

A) Vibroground test.
B) Continuity test.
C) Clamp-on test.
D) Earth resistance test.