26209-20 - Grounding & Bonding

When running a single 120v circuit from one building to another, how many ungrounded conductors will there be traveling to the second building?

1

NEC Section _____ describes grounding electrode conductor installations?

250.64

AC systems over _____ that supply mobile or portable equipment are required to be grounded?

1kV

According to figure 10 in 2.0.0, a plate electrode must expose not less than _____ square feet of surface to exterior soil?

2

Rod, pipe, and plate electrodes must have a resistance to ground of ______ or less?

25 Ohms

According to NEC Section _____, only six types of circuits shall not be grounded?

250.22

Referring to figure 13 in 2.0.0, what is the minimum length allowed for a ground rod?

8'

Rod and pipe electrodes shall not be less than _____ in length nor smaller than ______ trade size?

8' and 3/4"

Using NEC Sections 250.118(5), 348.60, and NEC Table 250.122, determine the size of the EGC for a flexible metal conduit connection to a motor supplied with a 30A circuit?

A No. 10 copper or No. 8 aluminum or copper-clad

NEC Section 250.102(C)(2) allows the use of _____ to bond two or more raceways or cables where the bonding jumper is sized in accordance with NEC Table 250.102(C)(1)?

A single conductor

A separately derived system can be defined as _____?

A system whose power is derived from a source other than a service

What is the name of the test that measures resistance of a grounding electrode utilizing an auxiliary current electrode and an auxiliary potential electrode?

A three-point test

Some examples of separately derived systems include_____?

All of the above

Which of the following are recognized by NEC Section 250.118 as being adequate for use as an equipment grounding conductor?

All of the above

NEC Table 250.66 gives the proper sizes of grounding electrode conuctors. The size of the service-entrance conductor is determined from the _____ of that system?

Ampacity

Bonding can be defined as _____?

Connected to establish electrical continuity and conductivity

What is the key to the successful clearing of ground fault currents?

Electrical continuity

A ground fault, as defined in NEC Article 100, is_____?

Electrically conducting connection between an ungrounded conductor in a circuit and the normally noncurrent-carrying conductors

NEC Section 250.53(D)(2) states that an underground water pipe must be supplemented by an additional _____ of a type specified in NEC Sections 250.52(A)(2) through 250.52(A)(8)?

Electrode

The _____ is the conductive path used to connect noncurrent-carrying metal parts of equipment, raceways and other enclosures?

Equipment grounding conductor

The _____ is used to interconnect and bond the noncurrent-carrying metal parts of equipment, raceways, and other enclosures to the system grounded conductor or the grounding electrode conductor, or both?

Equipment grounding conductor

The conductive path(s) that provide a ground-fault current path and connect normally noncurrent-carrying metal parts of equipment together can be defined as _____?

Equipment grounding conductor

True or False: By connecting a third wire (neutral) on the primary windings of a 240v transformer, you then have 120v between either leg A or leg B and the neutral conductor?

False

True or False: Electrical systems must be grounded in a manner perscribed by the NEC, but are not required to be Bonded?

False

True or False: If a neutral is not needed for voltage requirements, it is not required to be used in most applications?

False

True or False: NEC article 250, Informational note No. 1 recognizes that the equipment grounding conductor (EGC) also performs bonding?

False

True or False: Per NEC Section 250.64(C)(1), wire type grounding electrode conductors may only be spliced a total of 2 times throughout the entire length of the conductor?

False

True or False: The bonding requirements for an installation only depend on system voltage for the service?

False

True or False: When no grounding electrodes are installed at an additional structure, a grounding electrode is not required to be installed, unless the structure is supplied by a single branch circuit?

False

Conductive materials are bonded to establish electrical continuity and conductivity. This facilitates the operation of overcurrent devices under _____ conditions?

Ground fault

When service conductors are paralleled in two or more raceways the equipment bonding jumper shall be run _____?

In parallel

What a generator is not a separately derived system, what must be done with the system bonding jumper?

It must be removed from the generator and the neutral must not be grounded.

Service-entrance conductors are routed between the meter housing and _____?

Main service switch or panel

Methods of grounding an electric service are covered in _____?

NEC Article 250, Part III

_____ discusses whether or not a separately derived system is required to be grounded?

NEC Section 250.30

If the grounding electrode's for a separately derived system is located outside it must be installed in accordance with _____?

NEC Section 250.30(C)

If nonmetallic boxes are used with Type NM cable, are you required to connect the EGC to the boxes?

No

The size of the EGC is determined from the _____ according to NEC Table 250.122?

Size of the overcurrent device that is protecting that particular system

The two general classifications of protective grounding are _____?

System grounding and equipment grounding

NEC ______ is used to determine the size of the service conductor from its ampacity?

Table 310.16

If metallic boxes are used how do you ensure proper bonding of the box as well as any devices that may be used?

The EGC must be attached to the box via a grounding clip or grounding screw

If more than one EGC enters a metallic box with a device what must be done to ensure proper bonding?

The EGC's must be spliced independently from the device then one conductor is attached to the device

According to NEC Section 250.32, when installing grounding at multiple buildings, which on the following statements are true?

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

The higher the impedance on an equipment grounding conductor the _____?

The more opposition there is for current flow

NEC Table 250.102(C)(1) is used to determine the size of the main bonding jumper based on what?

The rating of the service conductors that supply the service

Why must all metallic noncurrent-carrying parts such as conduit, outlet boxes and enclosures of an electrical system be bonded together?

To ensure operation of overcurrent devices in case of ground faults

What is a ground tester used for?

To measure the resistance of the installed grounding electrode system to earth

One of the main purposes of a grounded conductor in an electrical circuit is_____?

To provide a low-impedance return path for fault current

Why must an effective ground fault path be established in an electrical circuit?

To provide a properly sized path to safely facilitate operation of the circuit protective devices

A supply-side bonding jumper is routed with the feeder conductors from the transformer to the equipment grounding bar in the panel when the bonding jumper is in the transformer?

True

True or False: A short cicuit is a conducting connection between any of the conductors of an electrical system, whether it is from line-to-line or from line-to-neutral (grounded)?

True

True or False: By connecting only 240v loads on a single phase 240v transformer the neutral would carry no current?

True

True or False: Equpment bonding jumpers are permitted to be installed either inside or outside of a raceway or enclosure?

True

True or False: If a ground rod, pipe or plate electrode has a resistance higher than 25 ohms to ground it must be augmented by an additional electrode spaced not less than 6' from the first?

True

True or False: NEC Article 250 is the primary governing article for the proper use and installation of grounding and bonding?

True

True or False: NEC Section 250.97 defines methods permitted to be used on circuits over 250v?

True

True or False: The bonding jumper is located on the supply of the service disconnect when bonding multiple service disconnects?

True

True or False: The fall-of-potential method is one of the most common methods used for measuring resistance to earth of a grounding electrode?

True

True or False: The grounding system's purpose is to protect life and equipment against various electrical faults that can occur?

True

True or False: The way to determine that a generator is a separately derived system is to examine the transfer switch. If the neutral and all phase conductors are switched, then the system is separately derived.

True

True or False: When installing a new grounding system it's recommended to perform three-point tests every season for the first year?

True

A grounded system must limit the voltage on the electrical system and protect it from all of the following except, Lightning, Voltage surges higher than that for which the circuit is designed, an increase in maximum potential to ground due to abnormal voltage, and vandalism?

Voltage surges higher than that for which the circuit is designed

When must you ground systems less than 50v?

Where supplied by transformers if the supply voltage to the transformer exceeds 150v to ground.

A wire used to connect a neutral conductor to a grounding electrode is referred to as a _____?

grounding electrode conductor