Midterm final questions
Circuit breakers and switches containing fuses shall be readily accessible and installed so the center of the grip of the operating handle of the switch or circuit breaker , when in its highest position , is not more than ===== above the floor or working platform .
6 ft 7 in .
Reconditioned circuit breakers shall be listed as âreconditionedâ and the original listing mark shall be
Removed
Overcurrent devices are not permitted to be located in the bathrooms of
dwelling units dormitories guest rooms or guest suites of hotels or motels
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
Where the circuit breaker handles are operated vertically , the " up " position of the handle shall be the __ " position .
on
A building or structure shall be supplied by a maximum of__________ service ( s ) , unless specifically permitted otherwise .
one
Circuit breakers shall ________________all ungrounded conductors of the circuit both manually and automatically unless specifically permitted otherwise .
open
If exposed structural metal that is interconnected to form the building frame exists in the area served by the separately derived system , it shall be bonded to the grounded conductor of each separately derived system and each bonding jumper shall be sized in accordance with Table 250.102 ( C ) ( 1 ) based on the largest grounded conductor of the service .
False
Where isolated metal water piping systems are installed in a multiple - occupancy building , the water pipes can be bonded with bonding jumpers sized in accordance with 250.104 ( D ) .
False
The frame of a vehicle - mounted generator shall not be required to be connected to a ( an ) if the generator only supplies equipment mounted on the vehicle or cord - and - plug - connected equipment , using receptacles mounted on the vehicle .
Ogrounding electrode
A grounding electrode conductor shall be permitted to be run to any convenient grounding electrode available in the grounding electrode system where the other electrode ( s ) , if any , is connected by bonding jumpers that are installed in accordance with 250.53 ( C ) .
True
A grounding electrode shall be required if a building or structure is supplied by a feeder . True false ?
True
A service disconnecting means shall not be installed in bathrooms . True or false?
True
Alternating - current systems of 50V to 1,000V that supply premises wiring systems shall be grounded where the system is three - phase , 4 - wire , wye connected , with the neutral conductor used as a circuit conductor . True or false
True
If the voltage between overhead service conductors does not exceed 300V and the roof area is guarded or isolated , a reduction in clearance to 3 ft is permitted .
True
Service conductors shall not be installed beneath openings through which materials may be moved and shall not be installed where they will obstruct entrance to these buildings ' openings .
True
Supplementary overcurrent devices used in luminaires or appliances are not required to be readily accessible True false?
True
Two or more common grounding electrodes that are bonded together shall be considered as a single grounding electrode system in this sense .
True
When installing auxiliary electrodes , the earth shall not be used as an effective ground - fault current path .
True
Where a building or structure is supplied by more than one service , a permanent plaque or directory shall be installed at each service disconnect location denoting all other services supplying that building or structure and the area served by each . True or false?
True
Where a mast is used for overhead branch - circuit or feeder conductor support , it shall have adequate strength or be supported by braces or guys to safely withstand the strain imposed by the conductors .
True
Where circuit conductors are installed in parallel in multiple raceways or cables and include an EGC of the wire type , the equipment grounding conductor shall be installed in parallel in each raceway or cable , sized in compliance with 250.122 based on the overcurrent protective device for the feeder or branch circuit .
True
Where dwelling unit service equipment is replaced , a surge protective device ( SPD ) shall be installed . True or false?
True
Wiring methods permitted for service - entrance conductors include rigid metal conduit electrical metallic tubing PVC conduit all of these
all of these
Fuses shall be marked with their
ampere and voltage rating interrupting rating where other than 10,000A name or trademark of the manufacturer
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
A listed exposed work cover shall be permitted to be the grounding and bonding means for a surface - mounted metal box if the ---
device is attached to the cover with at least two fasteners that are permanent ( such as a rivet ) or have a thread locking or screw or nut locking means , and the cover mounting holes are located on a flat non raised portion of the cover
A circuit breaker with a slash rating , such as 120 / 240V or 480Y / 277V , shall be permitted to be applied in a solidly grounded circuit where the nominal voltage of any conductor to ground the lower of the two values of the circuit breaker's voltage rating and the nominal voltage between any two conductors the higher value of the circuit breaker's voltage rating .
does not exceed
Expansion , expansion - deflection , or deflection fittings and telescoping sections of metal raceways shall be made_________ continuous by equipment bonding jumpers or other means .
electrically
Overcurrent protection for conductors and equipment is provided to___________ the circuit if the current reaches a value that will cause an excessive or dangerous temperature in conductors or conductor insulation .
open
Exposed structural metal interconnected to form a metal building frame that is not intentionally grounded or bonded and is likely to become energized , shall be bonded to the
service equipment enclosure or building disconnecting means grounded conductor at the service grounding electrode conductor where of sufficient size
There shall be no more than________________ disconnects installed for each service or for each set of service - entrance conductors as permitted in 230.2 and 230.40
six
A circuit breaker with a voltage rating , such as 240V or 480V , can be used where the nominal voltage between any two conductors does not exceed the circuit breaker voltage rating .
straight
Service - drop conductors shall have___________________
sufficient ampacity to carry the load and adequate mechanical strength
A conductor , other than a service conductor , that has overcurrent protection ahead of its point of supply that exceeds the ampacity permitted for similar conductors is known as a
tap conductor
The requirement to maintain a 3 - ft vertical clearance from the edge of a roof does not apply to the final conductor span where the service drop is attached to_________________
the side of a building
Ungrounded alternating - current systems from 50V to less than 1,000V shall be legibly marked " Caution : Ungrounded System - Operating ___ Volts Between Conductors " at of the system , with sufficient durability to withstand the environment involved .
the source or the first disconnecting means
In grounded systems , normally noncurrent - carrying electrically conductive materials that are likely to become energized shall be connected__________ in a manner that establishes an effective ground - fault current path .
together and to the electrical supply source
When sizing grounded conductors for parallel raceways installed for a separately derived ac system and the system bonding jumper is not located at the source , they shall also be installed in parallel and not smaller than___________
1/0 AWG
When taps are not over 10 ft in length for field installations , and they leave the enclosure or vault in which the tap is made , the ampacity of the tap conductors cannot be less than __________the rating of the device protecting the feeder .
1/10
Grounding electrodes of bare or electrically conductive coated iron or steel plates shall be at least ‒‒‒‒ — in . thick .
1/4
One or more metal in - ground support structure ( s ) in direct contact with the earth vertically for __________ ft or more , with or without concrete encasement is permitted to be a grounding electrode in accordance with 250.52 .
10
Overhead service conductors shall have a horizontal clearance of not less than_______ ft from a pool .
10
The point of attachment of overhead premises wiring to a building shall in no case be less than_____ ft above finished grade .
10
A building disconnecting means that supplies only limited loads of a single branch circuit shall have a rating of not less than
15A
Overcurrent protection shall not exceed______________?
15A for 14 AWG copper 20A for 12 AWG copper 30A for 10 AWG copper
Listed FMC can be used as the equipment grounding conductor if the length in any ground return path does not exceed 6 ft and the circuit conductors contained in the conduit are protected by overcurrent devices rated at _____________or less .
20A
Each tap conductor to a common grounding electrode conductor for multiple separately derived systems shall be sized in accordance with based on the derived ungrounded conductors of separately derived system it serves .
250.66
Overhead feeder and branch circuit clearance from chimneys , radio and television antennas tanks , and other nonbuilding or nonbridge structures , shall not be less than _____________ ft .
3
The vertical clearance of final spans of overhead conductors above or within 11 ft measured horizontally of platforms , projections or surfaces that will permit personal contact shall be maintained in accordance with 225.18 .
3
The vertical clearance of final spans of overhead service conductors above , or within _______________ ft measured horizontally of platforms , projections , or surfaces that will permit personal contact shall be maintained in accordance with 230.24 ( B ) .
3
The largest size grounding electrode conductor required is ===== copper .
3/0 AWG
Underground service conductors shall be protected from damage in accordance with ----- including minimum cover requirements .
300.5
Interior metal water piping that is electrically continuous with a metal underground water pipe electrode and is located not more than_____________ ft from the point of entrance to the building shall be permitted to extend the connection to an electrode ( s ) .
5
A ( An ) . AWG or larger copper or aluminum grounding electrode conductor exposed to physical damage shall be protected in rigid metal conduit , IMC , Schedule 80 PVC conduit , reinforced thermosetting resin conduit Type XW ( RTRC - XW ) , EMT , or cable armor
6
Overhead service conductors installed over roofs shall have a vertical clearance of not less than __________________ft above the roof surface , unless a lesser distance is permitted by an exception .
8
A rod or pipe electrode shall be installed such that at least __________of length is in contact with the soil .
8 ft
Conductors supplied under the tap rules are allowed to supply another conductor using the tap rules . True false?
False
Listed liquidtight flexible metal conduit ( LFMC ) is acceptable as an equipment grounding conductor when it terminates in listed fittings and is protected by an overcurrent device rated 60A or less for trade sizes 3/8 through 1/2 .
False
Circuit breakers used to switch 120V and 277V fluorescent lighting circuits shall be listed and marked____________
SWD or HID
A grounding electrode conductor , sized in accordance with 250.66 , shall be used to connect the equipment grounding conductors , the service - equipment enclosures , and , where the system is grounded , the grounded service conductor to the grounding electrode ( s ) . True False?
True
Grounding electrode conductor taps from a separately derived system to a common grounding electrode conductor are permitted when a building or structure has multiple separately derived systems , provided that the taps terminate at the same point as the system bonding jumper . True false?
True
Mechanical elements used to terminate a grounding electrode conductor to a grounding electrode shall be accessible .
True
Where more than one concrete - encased electrode is present at a building or structure , it shall be permitted to bond only one into the grounding electrode system . True false ?
True
Service heads on raceways or service - entrance cables and goosenecks in service - entrance cables shall be located ___________the point of attachment , unless impracticable .
above
The bonding jumper used to bond the metal water piping system shall be installed in accordance with 250.64 ( A ) , 250.64 ( B ) , and 250.64 ( E ) and the points of attachment of the bonding jumper ( s ) shall be
accessible
Outside feeder tap conductors can be of unlimited length without overcurrent protection at the point they receive their supply if the tap conductors
all of these
For adjustable - trip circuit breakers , restricted access is defined as
any of these
Service - entrance cables which are not installed underground , where subject to physical damage , shall be protected by rigid metal conduit IMC Schedule 80 PVC conduit any of these
any of these
Plug fuses of the Edison - base type shall be used only
as a replacement in existing installations
The intersystem bonding termination shall ---
be accessible for connection and inspection consist of a set of terminals with the capacity for connection of not less than three intersystem bonding conductors not interfere with opening the enclosure for a service , building / structure disconnecting means , or metering equipment
Where practicable rod , pipe , and plate electrodes shall be installed
below permanent moisture level
Electrical continuity at service equipment , service raceways , and service conductor enclosures shall be ensured by ____
bonding equipment to the grounded service conductor connections utilizing threaded couplings on enclosures if made up wrenchtight other listed bonding devices , such as bonding - type locknuts , bushings , or bushings with bonding jumpers
Short sections of metal enclosures or raceways used to provide support or protection of ______________from physical damage shall not be required to be connected to the equipment grounding conductor .
cable assemblies
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
Bare or covered aluminum or copper - clad aluminum grounding electrode conductors without an extruded polymeric covering shall not be installed where subject to corrosive conditions or be installed in direct contact with
concrete
The next higher standard rating overcurrent device above the ampacity of the ungrounded conductors being protected shall be permitted to be used , provided the
conductors being protected are not part of a branch circuit supplying more than one receptacle for cord and - plug - connected portable loads ampacity of the conductors does not correspond with the standard ampere rating of a fuse or circuit breaker next higher standard rating selected does not exceed 800A All of these
Electrical equipment secured to and in contact with a metal rack or structure provided for its support shall be permitted to be considered as being connected to an equipment grounding conductor if the metal rack or structure is connected to an equipment grounding conductor by one of the means indicated in 250.134 .
electrical
Conductors with insulation or individual covering that is _________ or otherwise identified by this section shall not be used for ungrounded or grounded circuit conductors .
green or green with one or more yellow stripes
Circuit breaker enclosures shall be permitted to be installed ----- where the circuit breaker is installed in accordance with 240.81
horizontally
Where conduits are used as service masts , hubs shall be ______________ for use with service - entrance equipment .
identified
A rebar - type concrete - encased electrode installed in accordance with 250.52 ( A ) ( 3 ) with an additional rebar section extended from its location within the concrete foundation or footing to an accessible location that is not subject to corrosion is permitted for connection of grounding electrode conductors and bonding jumpers providing the rebar
is continuous or effectively connected to the grounding electrode rebar extension is not in direct contact with the earth without corrosion protection is not used as a conductor to interconnect the grounding electrode system
Meter sockets supplied by and under the exclusive control of an electric utility shall not be required to be______________
listed
The service disconnecting means rated 1,000V or less shall be marked to identify it as being suitable for use as service equipment and shall be
listed or field evaluated
Equipment grounding conductors , grounding electrode conductors , and bonding jumpers shall be connected by
listed pressure connectors terminal bars exothermic welding
Grounded electrical systems shall be connected to earth . in a manner that will
límit voltages due to lightning , line surges , or unintentional contact with higher - voltage lines and stabilize the voltage - to - ground during normal operation
Where an ac system operating at 1,000V or less is grounded at any point , a ( an ) shall connect the grounded conductor ( s ) to each service disconnecting means enclosure .
main bonding jumper
For the continuity of equipment grounding conductors and attachment in boxes , a connection used for ___________ shall be made between the metal box and the equipment grounding conductor ( s ) in accordance with 250.8 .
no other purpose
Where the supply conductors are larger than 1,100 kcmil copper or 1,750 kcmil aluminum , the main bonding jumper shall have an area that is the area of the largest phase conductor when of the same material .
not less than 12 1/2 percent of
If a building or structure is supplied by a feeder from an outdoor separately derived system , a system bonding jumper at both the source and the first disconnecting means shall be permitted if doing so does not establish a ( an ) path for the grounded conductor .
parallel
Where multiple feeder conductors to a building originate in the same panelboard , switchboard , or other distribution equipment , and each feeder terminates in a single disconnecting means , not more than feeders shall be permitted .
six
For ungrounded systems , noncurrent - carrying conductive materials enclosing electrical conductors or equipment , or forming part of such equipment , shall be connected together and to the supply system grounded equipment in a manner that creates a low - impedance path for ground - fault current that is capable of carrying_____________________
the maximum fault current likely to be imposed on it
If a building or structure is supplied by a service or feeder with or more disconnecting means in separate enclosures , the grounding electrode connections shall be made in accordance with 250.64 ( D ) ( 1 ) , 250.64 ( D ) ( 2 ) , or 250.64 ( D ) ( 3 ) .
two
Where ungrounded supply conductors are paralleled in two or more raceways or cables , the bonding jumper for each raceway or cable shall be based on the size of the in each raceway or cable .
ungrounded supply conductors
Where a metal underground water pipe is used as a grounding electrode , the continuity of the grounding path or the bonding connection to interior piping shall not rely on and similar equipment .
water meters or filtering devices