1
CFESA ELECTRICAL PRACTICAL EXAMS WITH CORRECT
QUESTIONS AND ANSWERS 100% CERTIFIED/APPROVED BEST
GRADED A+
What is special about SO or SJO cord that makes it desirable in the commercial food service
industry? - answers-Grease and oil resistant
Ground wires must always be what color(s)? - answers-Green, green with yellow tracer, or bare
metal
Neutral wire(s) must always be what color? - answers-White
what size THHN wire should be used for a 20 amp load? - answers-12 gauge
What size TGGT wire should be used for a 30 amp load? - answers-12 gauge
What size SO cord should be used for a 40 amp load? - answers-8 gauge
Give three common reasons for wire failures - answers-undersized, temp rating too low, poor
connections
Why must burned or discolored wire be replaced? - answers-once burned or discolored the current
carrying capacity drops significantly. Also connections will overheat.
If you put new terminals on discolored wire what will happen? - answers-they will burn off again
Many high temp wire insulations will turn dark, or brown after a short period of use in high ambient
temps. What does this color change indicate? - answers-That the wax coating on the wire has
become hot from ambient conditions. this wire is usually still clean and fully functional.
Standard electric terminal clips are made of what materials? - answers-Copper or brass
, 2
What happens to standard terminals when used in high temp applications? - answers-they oxidize,
weaken, and burn off
High temp terminals are made of what materials? - answers-nickel, nickel tinned steel, or plain steel
what is the disadvantage of using high temp female quick disconnect terminals? - answers-they have
no memory. Once put on they loose their tension, if pulled of again and reinstalled they will be
loose.
Should insulated terminal clips be used in higher temp applications? - answers-No
What is the main difference between crimping tools used to crimp insulated terminals versus non-
insulated terminals? - answers-non insulated crimpers have sharper teeth to bite into the barrel of
the terminal
how far back should the wire insulation be stripped when using terminal clips? - answers-just
enough to fill the barrel of the terminal completely
how many crimps should be made in each terminal? - answers-2 if possible
how do you find the total resistance of a parallel circuit? - answers-1/RT = 1/R1 + 1/R2 + 1/R3 ...
If a circuit is wired parallel, and the supply voltage is 120 volts, each load must be rated at what
voltage? - answers-120 volts
if a circuit has two elements wired in series, and each is rated at 120 volts, what voltage must be
supplied to the circuit in order for the elements to heat at full power? - answers-240 volts
What is the advantage of using higher voltages? - answers-Lower Current and wire size
Is there a negative and positive line in AC power supplies? - answers-No
What is the voltage between two hot lines in a 230-volt system? - answers-230V
, 3
What is the voltage between two hot lines in a 208-volt system? - answers-208V
What is the voltage between a hot line and a neutral in a 230-volt single phase supply? - answers-
115V
What is the voltage between a hot line and a neutral in a 208-volt single phase supply? - answers-
120V
What is the accepted maximum voltage difference between the name plate voltage and the supplied
voltage? - answers-+ or - 10%
What is the voltage between any two hot lines of a 230 volt delta power supply? - answers-230V
what is the voltage between a hot line and ground on a 240 volt delta power supply - answers-No
usable voltage
what is the voltage between any two hot lines of a 230 volt grounded delta power supply - answers-
230V
draw a diagram of a 230 volt grounded delta power supply. label all of the voltages and the wild leg -
answers-
what is the wild leg? - answers-leg with higher than 120v to ground or neutral
what danger is the wild leg? - answers-high voltage that will damage 120v component in the circuit
what is the voltage between either of the non wild leg hot lines and neutral in a 230 volt grounded
delta system? - answers-115v
how do you determine which hot line is the wild leg in a 250 volt grounded delta power supply? -
answers-the one that does not measure 120 volts to neutral or ground
, 4
what danger is there when replacing a three phase circuit breaker in a 230 volt grounded delta
power supply? - answers-crossing the hot lines and supplying the wild leg to the wrong terminal in
the unit.
Why is a "WYE" power supply so versatile - answers-can get 120v and 208v as well as single and
three phase
What is the voltage between any two hot lines in a 208 volt WYE power supply? - answers-208v
What is the voltage between any hot line and neutral or ground in a 208 volt WYE power supply? -
answers-120v
What is the voltage from any hot line to ground or neutral, on a 480 volt WYE power supply? -
answers-277v
if you had a commercial building and you had a three phase supply to your building how many
different incoming power supplies would you need if the incoming three phase supply was three
phase delta? - answers-2
if you had a commercial building and you had a three phase supply to your building, how many
different incoming power supplies would you need if the incoming three phase supply was three
phase grounded delta? - answers-1
if you had a commercial building and you had a three phase supply to your building how many
different incoming power supplies would you need if the incoming three phase supply was three
phase WYE 208v? - answers-1
approximately how much will the wattage increase on a 208v piece of equipment if it is connected
to 240v supply? - answers-33%
approximately how much will the rated wattage decrease if a 240v unit is connected to a 208v
power supply? - answers-25%
what damage could potentially be caused to the supply wiring if 208v unit is connected to a 240v
supply? - answers-higher wattage created will damage heaters or other components
CFESA ELECTRICAL PRACTICAL EXAMS WITH CORRECT
QUESTIONS AND ANSWERS 100% CERTIFIED/APPROVED BEST
GRADED A+
What is special about SO or SJO cord that makes it desirable in the commercial food service
industry? - answers-Grease and oil resistant
Ground wires must always be what color(s)? - answers-Green, green with yellow tracer, or bare
metal
Neutral wire(s) must always be what color? - answers-White
what size THHN wire should be used for a 20 amp load? - answers-12 gauge
What size TGGT wire should be used for a 30 amp load? - answers-12 gauge
What size SO cord should be used for a 40 amp load? - answers-8 gauge
Give three common reasons for wire failures - answers-undersized, temp rating too low, poor
connections
Why must burned or discolored wire be replaced? - answers-once burned or discolored the current
carrying capacity drops significantly. Also connections will overheat.
If you put new terminals on discolored wire what will happen? - answers-they will burn off again
Many high temp wire insulations will turn dark, or brown after a short period of use in high ambient
temps. What does this color change indicate? - answers-That the wax coating on the wire has
become hot from ambient conditions. this wire is usually still clean and fully functional.
Standard electric terminal clips are made of what materials? - answers-Copper or brass
, 2
What happens to standard terminals when used in high temp applications? - answers-they oxidize,
weaken, and burn off
High temp terminals are made of what materials? - answers-nickel, nickel tinned steel, or plain steel
what is the disadvantage of using high temp female quick disconnect terminals? - answers-they have
no memory. Once put on they loose their tension, if pulled of again and reinstalled they will be
loose.
Should insulated terminal clips be used in higher temp applications? - answers-No
What is the main difference between crimping tools used to crimp insulated terminals versus non-
insulated terminals? - answers-non insulated crimpers have sharper teeth to bite into the barrel of
the terminal
how far back should the wire insulation be stripped when using terminal clips? - answers-just
enough to fill the barrel of the terminal completely
how many crimps should be made in each terminal? - answers-2 if possible
how do you find the total resistance of a parallel circuit? - answers-1/RT = 1/R1 + 1/R2 + 1/R3 ...
If a circuit is wired parallel, and the supply voltage is 120 volts, each load must be rated at what
voltage? - answers-120 volts
if a circuit has two elements wired in series, and each is rated at 120 volts, what voltage must be
supplied to the circuit in order for the elements to heat at full power? - answers-240 volts
What is the advantage of using higher voltages? - answers-Lower Current and wire size
Is there a negative and positive line in AC power supplies? - answers-No
What is the voltage between two hot lines in a 230-volt system? - answers-230V
, 3
What is the voltage between two hot lines in a 208-volt system? - answers-208V
What is the voltage between a hot line and a neutral in a 230-volt single phase supply? - answers-
115V
What is the voltage between a hot line and a neutral in a 208-volt single phase supply? - answers-
120V
What is the accepted maximum voltage difference between the name plate voltage and the supplied
voltage? - answers-+ or - 10%
What is the voltage between any two hot lines of a 230 volt delta power supply? - answers-230V
what is the voltage between a hot line and ground on a 240 volt delta power supply - answers-No
usable voltage
what is the voltage between any two hot lines of a 230 volt grounded delta power supply - answers-
230V
draw a diagram of a 230 volt grounded delta power supply. label all of the voltages and the wild leg -
answers-
what is the wild leg? - answers-leg with higher than 120v to ground or neutral
what danger is the wild leg? - answers-high voltage that will damage 120v component in the circuit
what is the voltage between either of the non wild leg hot lines and neutral in a 230 volt grounded
delta system? - answers-115v
how do you determine which hot line is the wild leg in a 250 volt grounded delta power supply? -
answers-the one that does not measure 120 volts to neutral or ground
, 4
what danger is there when replacing a three phase circuit breaker in a 230 volt grounded delta
power supply? - answers-crossing the hot lines and supplying the wild leg to the wrong terminal in
the unit.
Why is a "WYE" power supply so versatile - answers-can get 120v and 208v as well as single and
three phase
What is the voltage between any two hot lines in a 208 volt WYE power supply? - answers-208v
What is the voltage between any hot line and neutral or ground in a 208 volt WYE power supply? -
answers-120v
What is the voltage from any hot line to ground or neutral, on a 480 volt WYE power supply? -
answers-277v
if you had a commercial building and you had a three phase supply to your building how many
different incoming power supplies would you need if the incoming three phase supply was three
phase delta? - answers-2
if you had a commercial building and you had a three phase supply to your building, how many
different incoming power supplies would you need if the incoming three phase supply was three
phase grounded delta? - answers-1
if you had a commercial building and you had a three phase supply to your building how many
different incoming power supplies would you need if the incoming three phase supply was three
phase WYE 208v? - answers-1
approximately how much will the wattage increase on a 208v piece of equipment if it is connected
to 240v supply? - answers-33%
approximately how much will the rated wattage decrease if a 240v unit is connected to a 208v
power supply? - answers-25%
what damage could potentially be caused to the supply wiring if 208v unit is connected to a 240v
supply? - answers-higher wattage created will damage heaters or other components
