Grounding and Bonding

____ shall not be used as grounding electrodes.

-Metal underground gas piping systems and -Aluminum

Grounding electrodes of the wire-type can be ____.

-solid or stranded -insulated or bare

Tap connections to a common grounding electrode for multiple separately derived systems shall be made at an accessible location by _____.

-a connector listed as grounding and bonding equipment -listed connections to aluminum or copper bushbars -the exothermic welding process

Where conditions of maintenance and supervision ensure only qualified persons service the installation in ____ buildings, the entire length of the metal water piping system can be used for grounding purposes provided the entire length.... is exposed.

-industrial -institutional -commercial

Where service equipment consists of more than one enclosure, grounding electrode connections shall be permitted to be ____.

-multiple individual grounding electrodes -one grounding electrode at a common location -a common grounding electrode and taps

In an area served by a separately derived system, the ____ shall be connected to the grounded conductor of the separately derived system.

-structural steel AND -metal piping

Bonding jumpers from grounding electrodes shall be permitted to be connected to an aluminum or copper busbar not less than ____ thick and ____ wide and of sufficient length to accommodate the number of terminations necessary for the installation.

1/4 inches thick; 2 inches wide

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

In an arc system, if the size of the grounding electrode or bonding jumper connected to a concrete-encased electrode does not extend on to other types of electrodes that require a larger size of conductor, the grounding electrode shall not be required to be larger than ____ AWG copper.

4

For a separate building or structure supplied by a separately derived system when overcurrent protection is provided where the conductors originate, the supply conductors shall contain an ____.

equipment grounding conductor

If conductors are installed in parallel in the same raceway, a single wire-type conductor shall be permitted as the equipment grounding conductor and sized based on the ____ or ____ .

feeder; branch circuit

It shall be permissible to ground meter enclosures immediately adjacent to the service disconnecting means to the ____ circuit conductor on the load side of the service disconnect, if service ground-fault protection is not provided.

grounded

The frame of a portable generator shall not be required to be connected to a ____ if the generator only supplies equipment mounted on the generator, cord-and-plug connected equipment, or both.

grounding electrode

The receptacle grounding terminal of an isolated ground receptacle shall be connected to an ____ equipment grounding conductor run with the circuit conductors.

insulated

When a permanently installed generator ____, the requirements of 250.30 shall apply.

is a separately derived system

The common grounding electrode conductor installed for multiple separately derived systems shall be permitted to be a ____ pipe.

metal water

Lightning protection system ground terminals ____ be bonded to the building or structure grounding electrode system.

shall

A listed exposed work cover can be the grounding and bonding means when the device is attached to the cover with at least ____ permanent fasteners and the cover mounting holes are located on a non-raised portion of the cover.

two

Except as provided in 250.122 for raceway or cable tray installations, the equipment grounding conductor in each multiconductor cable shall be sized based on the ____.

overcurrent protective device for the feeder or branch circuit

For a single separately derived system, the grounding electrode connects to the grounded conductor of the derived system to the grounding electrode at the same point on the separately derived system where the _____ is connected.

system bonding jumper

A separate bonding jumper to the building's structural metal shall not be required if the metal frame of a building or structure is used as the ____ for the separately derived system.

grounding electrode

When ungrounded circuit conductors are increased in size to account for voltage drop, the wire-type equipment grounding conductor shall be proportionately increased in size according to the increase in size of the ungrounded conductors using their ____.

circular mil area

Where the supply-side bonding jumper of the wire type is run with the derived phase conductors from the source of a separately derived system to the first disconnecting means, it shall be sized based on _____.

the size of the derived ungrounded conductors