Article 250 (Cont')

Where used outside, aluminum or copper-clad aluminum grounding electrode conductors shall not be terminated within ____ in. of the earth.

18 in.

A bare 4 AWG copper conductor installed horizontally near the bottom or vertically, and within that portion of a concrete foundation or footing that is in direct contact with the earth, can be used as a grounding electrode when the conductor is at least _____ ft in length.

20

The largest size grounding electrode conductor required is ____ copper.

3/0 AWG

When a ground ring is used as a grounding electrode, it shall be installed at a depth below the earth's surface of not less than ____.

30 in. minimum

Grounding electrode conductors _____ AWG and larger that are not exposed to physical damage can be run along the surface of the building construction without metal covering or protection.

6

True or False: A grounding electrode at a separate bulding or structure shall be required where one multiwire branch circuit serves the building or structure.

False

True or False: A grounding electrode conductor shall be permitted to be run to any convenient grounding eletrode available in the grounding electrode system where the other electrode(s), if any, is connected by bonding jumpers that are installed in accordance with 250.53(C).

True

True or False: A grounding electrode shall be required if a building or structure is supplied by a feeder.

True

True or False: When supplying a grounded system at a separate building or structure, an equipment grounding conductor shall be run with the supply conductors and connected to the building or structure disconnecting means and to the grounding electrode(s).

True

A ground ring encircling the building or structure can be used as a grounding electrode when the _____.

ring is in direct contact with the earth, ring consists of at least 20 ft of bare copper conductor, and bare copper conductor is not smaller than 2 AWG