industrial study(1,2,4)
concrete incasement of raceways
12 in
3 phase windings are ___ apart.
120 degrees
fuse protection for transformers rated 1,000 volts or less current is less than 9 amps - set to no more than
167% of its value
most lightning standards required installation of
concrete base
plug- in busway fittings are _____ & ______
engineer and layed out well
fuse voltage ratings 2400 volts & up
true
for junction boxes and pulls
manholes
another term for pothead
stress cone
1/2 " conduit
7/8 " hole
high voltage fuses rating N or E
True
in industrial everything is 3-phase
True
maximum rating of over-current devices for transformers rated 1000 volts or higher ( 450.3(A) )
True
power or distribution panelboards can feed transformers
True
LIGHTNING ARRESTER
Protective device for limitting surge voltage on equipment by discharging or by-passing surge current
disconnect attached for busway system
circuit breaker cubicle
can adjust taps to
compensate voltage
Grounding
connecting an object to a large body, like Earth, that is capable of effectively removing an electric charge that the object might have ; connecting a circuit to a common point of reference
are given on the site plan to indicate the existing and new grading levels
contour lines
strain relief cord grip are used in
cord drop
for plug-in ducts torque or _______.
double torque
_________ replaces large conduit wire rated more or at 1,000 amps
feeder busways
methods of connecting paneboards ___ or _____ based on the _____ ( tap boxes )
feeder through lugs, double lugs , load
panelboards have access from the ____ and switchboard have access from the ____.
front, back
Delta delta will produce a ___
high leg
unlimited license used to work on
high voltage
input, transformer, output
high voltage, transformer, low voltage
the level of the lower edge of a conduit entering the manhole
invert elevation (INV)
fittings for feeder bus systems are ______ & ______ ( elbow, flat tee)
layed out and order
where lightning storm strikes ; provides low-impedance to ground
lightning arrester
underground raceways terminate in underground
manholes
TAPS not over 10FT long; ampacity of tap conductors is not less than _______ of the overcurrent device protecting the feeder conductors.
one-tenth ( 1/10)
TAPS not over 25FT long; ampacity of tap conductors is at least than _______ overcurrent device protecting the feeder conductors.
one-third ( 1/3)
can be installed directly in the soil
rigid metal conduit
open delta with ground will produce both ___ & ___. (usually out power 240 V)
singles phase and 3 phase
the connecting must be made in the _____ of each of the panelboard
subfeeder
the panelboard shall have a rating not less than _________.
the minimum feeder capacity
pothead
to terminate high voltage cables
plug-in ducts are to be properly ______ in a good manner
torque
getting power to places you need
trolley busway
busbar enclosed in ________ ducts ( busway, bus duct)
ventilated
Line current and phase current are the same in the _____ configuration.
wye
phase voltage is less than the line voltage by a factor of square root of 3 ( 1.732)
wye
taps provide ____ changes above/ below standard voltages.
2 1/2 %
panelboards available rating
225, 400, 600, 800, 1200 amps
for direct burial cables, minimum burial depth
24 inch
breakers usually rated at ____ or ____ volts
250, 600 volts
fuse protection for transformers rated 1,000 volts or less current is less than 2 amps - set no more than
300 % of its value
AIC
Ampere Interrupting Capacity
rating of the panelboard is determine by the ____
buses
panelboards with more than ____ of its overcurrent devices are rated at 30 amps or less, neutral connection provided are called ____ .
10 % , lightning panelboards
Most common type of connection is
Delta Delta
low impedance symbol
Z
substation
a set of equipment reducing the high voltage of electrical power transmission to that suitable for supply to consumers.
bonding
all metal parts connected, electrical continuity
is a reference point from which all elevations are located.
benchmark (BM)
the trip rating of the circuit breaker cannot exceed the ampacity of the ____ in the panelboard
busbar
Line voltage and phase voltage are the same in the _____ connection.
delta
the phase current is less than the line current by a factor of square root of 3 ( 1.732)
delta
panelboard must be protected using an protective device with a trip setting not exceeding the rating of the ____
panelboard