Graunding Flashcards
NEC 250.8 require that grounding must be?
Permanent reliable and continues graund
_______ is Connected together to establish electrical continuity and conductivity?
Bonding
System grounding and bonding relates to the?
Service-entrance equipment
A short circuit is a conducting connection whether intonational or accidental between any of the?
Conductor of an electrical system
Provide the grounding requirements for AC systems?
NEC 250.20 & 250.21
Grounding is require for systems
Less than 50v & if exceeds 150v
AC systems over 1000v must be grounded if the they supply?
Mobile or portable equipment
Separately derived system is a premises wiring system whose power is derived from a source of electrical energy other than a?
Service
Grounded system must limit the voltage on the electrical system and protect it from?
Lighting
Voltage surges
Requirements for grounding of service are found in?
NEC 250.24
Is made of at last 20 of no.2 or larger bare copper buried not less than 2.5 below grade
Grounding ring
Plates made of iron or steel must be at last?
1/4 thick
While nonferrous like copper only 0.06
Rod pipes and plates electrodes must have a resistance to ground of?
25 ohms or less
Plate electrode must expose not less than 2 square feet of surface to exterior soil must be bare or conductively coated iron or steel at least?
1/4 thick
Many locations require two electrodes and must be separate apart by?
No less than 6’ apart
is the sole connection between the grounding electrode and the ground system?
The grounding electrode conductor
Where the level of the rod has to be
Upper and of rod must be below permanent moisture level if practicable
Minimum pipe galvanize allow for used as grounding is?
3/4
Equipment grounding conductor refers to?
Connecting the no carrying metal parts of equipment or ground electrode conductor.
The size of EGC is determined by?
By the over current device
Metal boxes are grounded using a?
Grounding clip or green screw
Where the multiple conductors are larger than the maximum given in NEC 250.102 the main jumper cannot be less than?
12.5% of the area at the largest phase conductor.
Is the key to successful clearing of ground fault currents.
Electrical continuity
Continuity between services equipment and enclosures must be maintained by?
Bonding
Clearing ground faults Is protected by?
By opening of the over current device.
Maximum disconnect allow on a service?
6
Bonding jumper is locate on?
the supply side of the service disconnect.
Clearing ground fault the system will be protected by?
Overcurrent device
Grounded conductor it provides a?
low-impedance return path for the flow of fault current to the source to facilitate the operation of the overcurrent devices in the circuit.
Grounded conductor provides a
low-impedance return path for the flow of fault current to the source to facilitate the operation of the overcurrent devices in the circuit.
Neutral is not needed for voltage requirements it still must be run to the?
Service and connected to the grounded electrode conductor and equipment grounding conductor.
In a separated garage system the equipment bonding jumper is connected to?
System housing to Neutral bus bar
A grounding neutralizer earth ground resistance is known as?
Tree-point method
