|
1. |
240.21(C)(3) Industrial Installation Secondary Conductors not Over 25 feet Long. New item 1 added as condition as one of the conditions that must be met in order for this section to applied to field installations.
For industrial installations only, where the length of the secondary conductors does not exceed 7.5 m (25 ft) and complies with all of the following:
(1) [Added] Conditions of maintenance and supervision ensure that only qualified persons service the systems.
(2) The ampacity of the secondary conductors is not less than the secondary current rating of the transformer, and the sum of the ratings of the overcurrent devices does not exceed the ampacity of the secondary conductors.
(3) All overcurrent devices are grouped.
(4) The secondary conductors are protected from physical damage by being enclosed in by other approved means.
Question: One of the conditions for applying the 25 foot transformer tap rule is that only _________ persons service the installation.
|
|
|
|
|
|
|
|
|
a)
|
licensed electricians
|
|
b)
|
qualified
|
|
c)
|
engineers
|
|
|
|
|
|
|
|
2. |
240.21(H) Battery Conductors. This is a new requirement to allow the overcurrent protection for battery conductors to be located as close a practicable to the battery terminals but in an unclassified location.
The new rule states: Overcurrent protection shall be permitted to be installed as close as practicable to the storage battery terminals in a non-hazardous location. Installation of overcurrent protection within a hazardous location shall also be permitted.
Question: The new rule for locating battery overcurrent protection ______ contains a requirement for maximum length of battery conductors.
|
|
|
|
|
|
|
|
|
a)
|
does
|
|
b)
|
does not
|
|
|
|
|
|
|
|
3. |
240.24(F) Not Located Over Steps. This is a new requirement that makes it perfectly clear that "overcureent devices shall not be located over steps of a stairway."
Question: Overcurrent devices shall not be located over _____________ .
|
|
|
|
|
|
|
|
|
a)
|
steps
|
|
b)
|
porch way
|
|
c)
|
stairway landing
|
|
d)
|
steps of a stairway
|
|
|
|
|
|
|
|
4. |
240.86(A) Selected Under Egineering Supervison in Exisitng Installations. A new sentence has been added that says, "For calculated applications, the engineer shall ensure that the downstream circuit breaker(s) that are part of the series combination remain passive during the interruption period of the line side fully rated current-limiting device."
Question: For calculated applications, the engineer shall ensure that the downstream circuit breaker(s) that are part of the series combination remain __________ during the interruption period of the line side fully rated current-limiting device.
|
|
|
|
|
|
|
|
|
a)
|
active
|
|
b)
|
passive
|
|
|
|
|
|
|
|
5. |
240.92(B) Feeder Taps [for supervised industrial locations] A new Table Table 240.92(B) has been added delineating formulas that can be used for sizing tap conductors. The new section states For feeder taps specified in 240.21(B)(2), (B)(3), and (B)(4), the tap conductors shall be permitted to be sized in accordance with Table 240.92(B).
Question: For feeder taps table 240.92(B) gives ______ for calculating short circuit current ratings.
|
|
|
|
|
|
|
|
|
a)
|
values
|
|
b)
|
formulas
|
|
|
|
|
|
|
|
6. |
250.4(B)(4) Path for Fault Current. A revision has been made to this section for ungrounded systems to address the problem of a second ground fault from a different phase.
Electrical equipment, wiring, and other electrically conductive material likely to become energized shall be installed in a manner that creates a low-impedance circuit from any point on the wiring system to the electrical supply source to facilitate the operation of overcurrent devices should a second ground fault from a different phase occur on the wiring system. The earth shall not be considered as an effective fault-current path.
Question: If a second phase to ground fault occurs in an ungrounded system the ground fault path shall be _____________ in order to facilitate the operation of overcurrent devices.
|
|
|
|
|
|
|
|
|
a)
|
through the grounding electrode system
|
|
b)
|
through the ground
|
|
c)
|
low impedance
|
|
|
|
|
|
|
|
7. |
250.8 has been revised into a list format and all references to sheet metal screws have been removed. Connection of Grounding and Bonding Equipment.
(A) Permitted Methods. Grounding conductors and bonding jumpers shall be connected by one of the following means:
(1) listed pressure connectors
(2) Terminal bars
(3) Pressure connectors listed as grounding and bonding equipment
(4) Exothermic welding process
(5) Machine screw-type fasteners that engage not less than two threads or are secured with a nut
(6) Thread-forming machine screws that engage not less than two threads in the enclosure
(7) Connections that are part of a listed assembly
(8) Other listed means
Question: Self threading machine screws that are used for grounding must engage no less than _______ threads in the enclosure or be secured with a nut.
|
|
|
|
|
|
|
|
|
a)
|
one
|
|
b)
|
two
|
|
c)
|
three
|
|
|
|
|
|
|
|
8. |
250.20 and FPN No. 1 This section has been revised to make it clear that when a neutral of an alternate source of power or generator(s) as shown in the diagram is transferred by the transfer switch then the generator(s) is a separately derived system and is required to have its separate grounding electrode and grounding electrode conductor. If the neutral is not switched but is solidly connected between the alternate source of power and the utility, the generator as shown would not be a separately derived ac system.
Question: Generators that are separately derived systems with a neutral conductor _________ to have a grounding electrode.
|
|
|
|
|
|
|
|
|
a)
|
are required
|
|
b)
|
are not required
|
|
|
|
|
|
|
|
9. |
250.30(A)(4) Grounding Electrode Conductor, Multiple Separately Derived Systems. A new sentence has been added to this section: The grounding electrode conductor tap connection shall be made at the same point on the separately derived system where the system bonding jumper is installed.
Question: The connection of a grounding electrode tap to a separately derived systems shall be made _____________________ .
|
|
|
|
|
|
|
|
|
a)
|
at the grounding electrode connection
|
|
b)
|
at the same point on the separately derived system where the system bonding jumper is installed.
|
|
c)
|
at the service
|
|
|
|
|
|
|
|
10. |
250.32(B) Exception. The permission to use the grounded conductor for grounding at a separate building or structure for existing installations has been placed into an exception. For new installations the grounding conductor shall be required to be run to separate buildings or structures.
Question: For existing installations the grounded conductor is permitted for grounding at a separate building or structure if _____________________________ .
|
|
|
|
|
|
|
|
|
a)
|
there is no equipment grounding conductor run to the separate building or structure.
|
|
b)
|
There is no continuous metallic paths between the first building of structure and the separate building or structure.
|
|
c)
|
The is no supply side GPE
|
|
d)
|
All of the above
|
|
|
|
|
|
|