Module 26209-20 grounding and bonding
How many ungrounded conductors must be taken from the first structure to where the service is located in the second structure when running 120V between buildings?
1
if the voltage drop between a grounding electrode, and an auxiliary potential electrode is 10 V and a current of 10A is past between an auxiliary current electrode, and the grounding electrode, then the resistance is____?
1 ohm
Service conductors are sized using____?
NEC table 310.16
The EGC for a flexible metal conduit connection to a motor supplied with a 20A circuit is
12 AWG copper
A transformer supplied system operating out less than 50 V must be grounded if the supply voltage to the transformer exceeds_____?
150 V to ground
A ground ring consisting of 20' of No. 2 bare copper must be buried no less than _____.
2.5' below grade
If you are bonding multiple disconnects and the size of the service conductor is 1,000 kcmil in a wire way, the size of the bonding jumper is
2/0 copper
Assuming the use of 75 Celsius copper conductors, a 200A commercial service would require
3/0 service conductor
The main bonding jumper for 3/0 service conductors is
4 awg copper
A single phase system has two legs, Leg A and Leg B. If leg A is carrying 50A and Leg B is carrying 45A, the current being carried by the neutral is____?
5A
when an equipment bonding jumper is installed outside a raceway, the length is limited to not more than____?
6' (1.8m)
when completing a three-point test, the potential electrode is placed at_____?
62% of the current electrode distance
The minimum length allowed for driven ground rods under normal conditions is____
8'
Which type of system is required to be grounded
AC systems over 1kV that supply mobile or portable equipment
which of the following is considered a separately derived system?
An emergency standby system with an isolated neutral
A ground rod must be installed in a coastal location and can only be driven halfway before encountering a rock shelf. One alternative is to
Bury the rod in a trench at least 30" (750mm) deep
when using non-metallic boxes with type NM cable, the grounding wire ____?
Is not required to be connected to the box
Which of the following is true of the neutral in a grounded system
It provides a low-impedance return path for the flow of fault current to the source.
when grounding at more than one building, the GEC AT THE SECOND BUILDING IS SIZED____?
NEC table 250.66
The bonding jumper for multiple disconnecting means is located_____?
On the supply side of the service disconnect
The main bonding jumper is sized based on the size of the____?
Service conductors
The size of the equipment, grounding conductor is determined by the size of the____?
System over Current device
Which of the following is true when installing grounding at more than one building?
The grounded circuit conductor and the equipment grounding conductor must both be extended to the second building.
which of the following is true when two or more equipment grounding conductors enter an outlet box?
The grounding conductors are first connected using an approved method, then one wire is connected to the grounding terminal on the receptacle.
Equipment grounding refers to connecting the normally noncurrent carrying metal parts of equipment to the system, grounded conductor, and or____?
The grounding electrode conductor
to be affective, a grounding system must limit the voltage on the electrical system, and protect it from_____?
Voltage surges
The fall-of-potential method is used to measure _______?
earth resistance
The key to successfully clearing ground fault currents is _____.
electrical continuity
A ground fault is described as an unintentional
electrically conducting connection between an ungrounded conductor of an electrical circuit and the normally non-current-carrying conductors
Suppose a loose connection has an exposed bare conductor and it contacts the edge of a metal enclosure. Is this an example of a short circuit or ground fault
ground fault
If Single-Gang Nail-On non-metallic boxes are used with NM cable, which of the following is TRUE regarding grounding, conductor connections?
no grounding conductor connection to the box is required
According to the NEC, the path to ground from circuits, equipment, and metal enclosures must
provide a permanent and continuous path sized to safely conduct potential fault current
A ground tester can be used to measure the value of a grounding electrode's _____.
resistance
When a new grounding system has been installed, it is advisable to conduct baseline three-point tests every _____.
season for the first year
A generator system that supplies power where the neutral is NOT CONNECTED to the utility system, such as for carnivals, is known as a(n) _____.
separately derived system
A transformer bonding jumper is routed with the feeder conductors from the transformer to the equipment grounding bar in the panel and is known as a(n) _____.
supply-side bonding jumper
Metallic noncurrent-carrying parts of an electrical system are bonded together to ensure _____.
the proper operation of overcurrent devices in the event of a ground fault
A ground test utilizing an auxiliary current electrode and an auxiliary potential electrode is known as the _____.
three-point test
