A worker needs to repair the HVAC in Francis Hall. He goes into the first floor mechanical room to shut off the power to the Air Handler. What will he place on the switch inside of the breaker box after he shuts power off to the system?
LOTO
Arc Flash
NEC
XFMR
LOTO can be placed on both Disconnects and Switches inside of Control Panels?
How many volts are in OH1 coming to a building?
12,000
600
240
408
Which unit is a Transformer altering?
Volts
VA
Amps
Watts
What does a transformer do?
Steps-up/steps-down voltage
Only steps-up voltage
Only steps-down voltage
Steps-up/Steps-down amperage
_____ come off of the transformer and go to the building.
OH1
OH2
Meter
Weather Head
what is the purpose of a Weather Head?
protects electrical wire from rainwater
the point of the conduit where wire sticks out
allows electrician to get head in bad weather
allows wire to bend
what is the purpose of a guy wire?
purely structural, no power going to them.
it is a ground wire for the overhead powerlines.
it feeds to the underground transformer.
it does not do anything.
what is the difference between OH 1-phase and OH 3-phase?
Nothing, they are the same.
OH 1-phase has 1 transformer and a OH 3-phase has 3 transformers
OH 1-phase has 3 transformer and a OH 3-phase has 1 transformers
OH 3-phase can only be mounted on concrete poles while OH 1-phase can only be placed on a wooden pole.
an OH power line needs to reach a pad mounted transformer underground, however a large light pole is in the way of travel. what electrical device will be installed to fix this issue?
a pull box - able to pull the line from the OH line, then can send wire to the pad mounted transformer.
another transformer - able to pull the line from the OH line, then cam send the wire to the pad mounted transformer.
a meter - an electrical meter is able to read the power leaving the OH line and sends that information to the transformer.
transfer to a single phase OH from a three phase OH
what is the difference between a Transformer and a Pull Box?
Pull Boxes make a humming noise.
Transformer makes a humming noise.
__________ is the pressure in wire.
voltage
amperage
power
__________ is the flow in wire.
volts x amps = __________
watts
current
an unsupervised open transformer is perfectly safe and nothing to worry about
what is the purpose of a disconnect switch?
able to shut off power
switches between AC and DC
pathway for wire
acts like a junction box
an electrician is indoors, in air-conditioned space, pulling wire through a conduit that is threaded. what is wrong with this scenario?
electrician is doing nothing wrong.
electrician is pulling wire through an IMC/RMC
electrician is pulling wire through EMT
electrician is pulling wire through PVC
EMT pipe is connected in two ways:
compression
set screws
threaded
cement/glue
Thickest pipe wall is _____
RMC
IMC
EMT
this conduit is better at taking physical damage, better than EMT at resisting corrosion.
IMC/RMC
PVC
Copper
Aluminum
this conduit is BEST at running conduit underground.
PVC is great at running conduit above ground
EMT Stands for Electrical Metallic Tubing
EMT can be ran underground
EMT comes in _____ lengths
10'
5'
20'
1'
from running conduit outside of the home to inside of the home, what is used to make the transition?
Line Box (LB)
Junction Box (J-Box)
Flex Conduit
Pull Box
What is the 360 degree rule?
when four 90 degree bends have been made for conduit, a junction box needs to be placed to reset the degree of bends to 0.
You can not twist wire more than 360 degrees when pulling wire.
flex conduit is only to be used when wire needs to go around an object
you have to have conduit on all four sides of the junction box
What is the purpose of a Pull Box?
usually outdoors - acts as a pull point for wire, wire connection protection, and able to change wire direction.
need to have it before any transformer.
acts the same as a transformer just larger. can be able to handle more voltage.
usually indoors - acts as a pull point for wire, wire connection protection, and able to change wire direction.
what is the purpose of a junction box?
Need to have it before any indoor transformer,
Replaces the need of flex-conduit.
What is the difference between In-Line Metering and CT Metering?
In-Line Metering - the meter and the disconnect box are inline. While CT Metering - the meter and the disconnect box are not inline.
In-Line Metering - the meter and the disconnect box are not inline. While CT Metering - the meter and the disconnect box are inline.
In-Line Metering - the meter and the disconnect box are inline. While CT Metering - the meter and the disconnect box are inline.
In-Line Metering - the meter and the disconnect box are not inline. While CT Metering - the meter and the disconnect box are not inline.
the breaker box is the beginning of the circuit
what is a switch board?
distributes loads to several smaller load circuits (breaker panels).
steps-down voltage from underground to building
reduces volts from 12000 to 600
board to switch between one-pole, two-pole, and three-pole
what are panelboards?
divides electrical power into branch circuits throughout a building.
feed power to transformers.
feed power to switchboards.
1-phase breaker box
what is a dead front?
covers the back of a panelboard. covers the wires.
a wire that has no charge. dead
a load (lightbulb) that has no power going to it.
a breaker switch that has been tripped.
What is a Main Circuit Breaker (MCB)
A circuit breaker that has a main switch on the dead front allowing to shut off all of the circuits within the breaker at one.
a circuit breaker that does not have a main switch on the dead front. have to shut off all of the circuits manually one at a time.
the main switch board that gets the power from the transformer.
if a building that only has one circuit breaker.
What is a Main Lug Only (MLO) breaker
An Electrician is running conduit from the slab to the MCB outside. What conduit will you need to make sure he is installing?
MC Cable
there are total of 3 phases. what are they?
1-phase, 3-phase low, 3-phase high.
1-phase, 3-phase medium, 3-phase high.
1-phase, 2-phase, 3-phase.
1-phase low, 1-phase high, 3-phase.
1-phase voltage has the combination of __________
120/240
120/208
277/480
110/220
3-phase voltage has the combination of __________
3-phase low voltage has the combination of __________
3-phase high voltage has the combination of __________
what is the difference between 1-phase and 3-phase?
1-phase has a 3-wire configuration and a 3-phase has a 4-wire configuration.
1-phase uses black, red, and blue as hot wires and 3-phase uses brown, orange (or purple), and yellow as hot wires.
1-phase can have 1 and 3 pole configurations while 3-phase can have 1, 2, or 3 poles.
1-phase can use either a pole mounted or a on-ground transformer while a 3-phase can only use a ground mounted.
3-phase high can use a pole mounted transformer.
you see an electrician installing a transformer and is installing wire that is black, red, blue and brown, orange, and yellow. what is happening?
the electrician is setting up an interior 3-phase transformer. going from high to low 3-phase.
the electrician is setting up an exterior 3-phase transformer. going from high to low 3-phase.
the electrician is setting up an interior 3-phase transformer. going from low to high 3-phase.
the electrician is setting up an exterior 3-phase transformer. going from low to high 3-phase.
120/240V is the same as 240/120V
the feeder is conduit and wire that enters a circuit panel and branches leave the circuit panel providing individual circuits to rooms/appliances.
feeders entering the circuit panels have __________
big wires (large amps)
small wires (small amps)
big wires (small amps)
small wires (large amps)
flex conduit is also known as metal clad cable
amps drive wires size. small wire = low amps large wire = high amps
which statement is true about the National Electric Code?
for equipment operating at 600 volts, electrical panels must have a minimum of 3 ft.
for equipment operating at 800 volts, electrical panels must have a minimum of 4 ft.
for equipment operating at 800 volts, electrical panels must have a minimum of 8 ft.
for equipment operating at 600 volts, electrical panels must have a minimum of 6 ft.
choose which statement is correct.
the NEC requires the area under and above a CB to be only for electrical items only. plumbing and other items are prohibited.
the NEC requires the area under a CB to be only for electrical items only. plumbing and other items are prohibited.
the NEC requires the area above a CB to be only for electrical items only. plumbing and other items are prohibited.
The NEC does not have any statements on whether you need a clear area above or below a CB
choose which statement is accurate.
the NEC requires a main disconnect switch if there are more than 6 mini-disconnects outside.
the NEC requires a main disconnect switch if there are more than 8 mini-disconnects outside.
the NEC requires a main disconnect switch if there are more than 4 mini-disconnects outside.
the NEC requires a main disconnect switch if there are more than 10 mini-disconnects outside.
There is a heavy storm in town and you're at home with your whining dog, rain and wind come and take your service power out, however, in seven seconds, your power is restored but now you hear a humming noise coming from the side of your house. what just happened?
your Automatic Transfer Switch (ATS) kicked into action and turned on the Generac to keep the house powered until Center Point can get power back on the grid.
Center Point lost power but it came back on in seven seconds.
Center Point lost power for seven seconds but it came back in seven seconds. The humming is the transformer making noise.
your Un-Interruptible Power Supplies (UPS) kicked into action and turned on the Generac to keep the house powered until Center Point can get power back on the grid.
Hospitals use this to have no interruption if power goes out. Do not even know power went out. A room that has batteries that can keep the building powered until an alternate source of energy is supplied to the building like a Generator or the Utility Company gets power back.
Un-Interruptible Power Supplies (UPS)
Automatic Transfer Switch (ATS)
Transformer
Main Circuit Breaker
1-phase systems are known as __________
3 wire system
1 wire system
2 wire system
4 wire system
3-phase systems are known as __________
which is true about a single phase?
240 is the line-to-line
120 is the line-to-neutral
480 is the line-to-line
277 is the line-to-neutral
208 is the line-to-line
which is true about a three phase high?
which is true about a three phase low?
how can you tell the difference between a three-phase low and a single-phase circuit panel?
three-phase circuit panel has a black, red, and blue hot, white neutral, and green ground.
single-phase circuit panel has a black, red, and blue hot, white neutral, and green ground.
single-phase circuit panel has a black, and red hot, white neutral, and green ground.
three-phase circuit panel has a black, and red hot, white neutral, and green ground.
three-phase high has brown, orange/purple, and yellow hot wires.
Romex is used primarily in commercial construction
The 6'7" rule is for what?
The maximum height of a breaker switch is 6'7"
The maximum distance any equipment near the breaker panel is 6'7"
The minimum height of a breaker switch is 6'7"
The minimum distance any equipment near the breaker panel is 6'7"
the National Electric Code has a 6 handle rule. Meaning, that if a building has less than 6 disconnect, it does not need a main disconnect.
__________ is the least efficient lighting.
Incandescent
LED
Fluorescent
__________ lighting is hazardous for disposal.
__________ lighting is the most efficient.
blue light is 10,000K
yellow light is 3000K
Warm Light ------------------------------------------------Cool Light 10,000K----------------------------------------------------------1,000K
This is an example of a lay-in fixture, troffer, or a grid mounted lighting fixture.
Pendant fixtures have one cable/support suspending from a surface.
High bay/suspended lighting fixtures are at least 15' from the FFE
Recessed fixtures are flush mounted
surface lighting fixtures are stuck to the surface of a ceiling.
track mounted lighting are adjustable in direction and can be removed from the track.
an inverter is only for emergency lighting.
__________ is a popular option for emergency lighting.
bug eye
frog eye
track mounted
surface mounted
structure mounted
sconce
the chevron(s) arrows frog eye bug eye( chevron(s), arrows, frog eye, bug eye ) on the EXIT signs indicate direction out in( out, in ) of the building
two options for controlling exterior lighting at night time.
photo cell
timer
light cell
wall packs
flag lights are usually placed at the top of a light pole
how can someone be electrocuted from a power line?
touching two lines at the same time.
touching the ground
no way to avoid it.
touching a single line
grounding is NOT needed on a building in order to function
grounding is simply a safety feature.
electrons travel underground when grounded
you can have a ground on a conduit inside of the building.
grounding moves the electrons from the load back to the __________ (final destination)
power source
ground
main distribution panel
electrical meter
answer based on if the information in the image is correct
leaders are put on top of buildings for __________________
lightning protection - path for lightning to go around the building rather than through the building
lightning protection - path for lightning to go in the building rather than around the building
electrocution protection - path for lightning to go around the building rather than through the building
electrocution protection - path for lightning to go in the building rather than around the building
3-pole breakers ONLY use 3 phase
only 1-pole and 2-pole breakers use a single phase.
Por favor espera - en proceso…