CFESA ELECTRICAL EXAM
QUESTIONS WITH VERIFIED ANSWERS
2026/2027 LATEST UPDATE
What is the voltage between any two hot lines of a 230 volt delta power
supply? - CORRECT ANSWER>>>>230V
what is the voltage between a hot line and ground on a 240 volt delta
power supply - CORRECT ANSWER>>>>No usable voltage
what is the voltage between any two hot lines of a 230 volt grounded
delta power supply -
CORRECT ANSWER>>>>230V
draw a diagram of a 230 volt grounded delta power supply. label all of
the voltages and the wild
leg - CORRECT ANSWER>>>>
what is the wild leg? - CORRECT ANSWER>>>>leg with higher than
120v to ground or neutral
what danger is the wild leg? - CORRECT ANSWER>>>>high voltage
that will damage 120v component in the circuit
1|Page
,what is the voltage between either of the non wild leg hot lines and
neutral in a 230 volt grounded delta system? - CORRECT
ANSWER>>>>115v
how do you determine which hot line is the wild leg in a 250 volt
grounded delta power supply? - CORRECT ANSWER>>>>the one that
does not measure 120 volts to neutral or ground
what danger is there when replacing a three phase circuit breaker in a
230 volt grounded delta power supply? - CORRECT
ANSWER>>>>crossing the hot lines and supplying the wild leg to the
wrong terminal in the unit.
Why is a "WYE" power supply so versatile - CORRECT
ANSWER>>>>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? - CORRECT
ANSWER>>>>208v
What is the voltage between any hot line and neutral or ground in a 208
volt WYE power supply? - CORRECT ANSWER>>>>120v
What is the voltage from any hot line to ground or neutral, on a 480 volt
WYE power supply? - CORRECT ANSWER>>>>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? -
CORRECT ANSWER>>>>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? - CORRECT ANSWER>>>>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? -
CORRECT ANSWER>>>>1
approximately how much will the wattage increase on a 208v piece of
equipment if it is connected to 240v supply? - CORRECT
ANSWER>>>>33%
approximately how much will the rated wattage decrease if a 240v unit
is connected to a 208v power supply? - CORRECT ANSWER>>>>25%
what damage could potentially be caused to the supply wiring if 208v
unit is connected to a 240v supply? - CORRECT ANSWER>>>>higher
wattage created will damage heaters or other components
3|Page
, What do the following prefixes mean? Micro,Kilo,Mega,Milli -
CORRECT
ANSWER>>>>1/1,000,000, 1000, 1,000,000, 1/1000
If you know the wattage and voltage, how do you determine the current?
- CORRECT ANSWER>>>>Divide the wattage by the voltage
If you know the voltage and current how do you determine the wattage?
- CORRECT ANSWER>>>>Multiply voltage times current
If a circuit is supplied with 100 volts and the total resistance of the
circuit is 200 ohms, how much current will the circuit draw? -
CORRECT ANSWER>>>>.5 amps
If a piece of equipment is supplied 208 volts and the amp meter clamped
to the hot line reads 20 amps, what is the wattage of the load? -
CORRECT ANSWER>>>>4160 Watts
How much voltage is in one hot line? - CORRECT
ANSWER>>>>None
What happens to current in a parallel circuit? - CORRECT
ANSWER>>>>It divides across resistances
what happens to voltage across the loads in a parallel circuit? -
CORRECT ANSWER>>>>stays the same
what happens to the voltage across the loads in a series circuit? -
CORRECT ANSWER>>>>it divides across the resistances
QUESTIONS WITH VERIFIED ANSWERS
2026/2027 LATEST UPDATE
What is the voltage between any two hot lines of a 230 volt delta power
supply? - CORRECT ANSWER>>>>230V
what is the voltage between a hot line and ground on a 240 volt delta
power supply - CORRECT ANSWER>>>>No usable voltage
what is the voltage between any two hot lines of a 230 volt grounded
delta power supply -
CORRECT ANSWER>>>>230V
draw a diagram of a 230 volt grounded delta power supply. label all of
the voltages and the wild
leg - CORRECT ANSWER>>>>
what is the wild leg? - CORRECT ANSWER>>>>leg with higher than
120v to ground or neutral
what danger is the wild leg? - CORRECT ANSWER>>>>high voltage
that will damage 120v component in the circuit
1|Page
,what is the voltage between either of the non wild leg hot lines and
neutral in a 230 volt grounded delta system? - CORRECT
ANSWER>>>>115v
how do you determine which hot line is the wild leg in a 250 volt
grounded delta power supply? - CORRECT ANSWER>>>>the one that
does not measure 120 volts to neutral or ground
what danger is there when replacing a three phase circuit breaker in a
230 volt grounded delta power supply? - CORRECT
ANSWER>>>>crossing the hot lines and supplying the wild leg to the
wrong terminal in the unit.
Why is a "WYE" power supply so versatile - CORRECT
ANSWER>>>>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? - CORRECT
ANSWER>>>>208v
What is the voltage between any hot line and neutral or ground in a 208
volt WYE power supply? - CORRECT ANSWER>>>>120v
What is the voltage from any hot line to ground or neutral, on a 480 volt
WYE power supply? - CORRECT ANSWER>>>>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? -
CORRECT ANSWER>>>>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? - CORRECT ANSWER>>>>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? -
CORRECT ANSWER>>>>1
approximately how much will the wattage increase on a 208v piece of
equipment if it is connected to 240v supply? - CORRECT
ANSWER>>>>33%
approximately how much will the rated wattage decrease if a 240v unit
is connected to a 208v power supply? - CORRECT ANSWER>>>>25%
what damage could potentially be caused to the supply wiring if 208v
unit is connected to a 240v supply? - CORRECT ANSWER>>>>higher
wattage created will damage heaters or other components
3|Page
, What do the following prefixes mean? Micro,Kilo,Mega,Milli -
CORRECT
ANSWER>>>>1/1,000,000, 1000, 1,000,000, 1/1000
If you know the wattage and voltage, how do you determine the current?
- CORRECT ANSWER>>>>Divide the wattage by the voltage
If you know the voltage and current how do you determine the wattage?
- CORRECT ANSWER>>>>Multiply voltage times current
If a circuit is supplied with 100 volts and the total resistance of the
circuit is 200 ohms, how much current will the circuit draw? -
CORRECT ANSWER>>>>.5 amps
If a piece of equipment is supplied 208 volts and the amp meter clamped
to the hot line reads 20 amps, what is the wattage of the load? -
CORRECT ANSWER>>>>4160 Watts
How much voltage is in one hot line? - CORRECT
ANSWER>>>>None
What happens to current in a parallel circuit? - CORRECT
ANSWER>>>>It divides across resistances
what happens to voltage across the loads in a parallel circuit? -
CORRECT ANSWER>>>>stays the same
what happens to the voltage across the loads in a series circuit? -
CORRECT ANSWER>>>>it divides across the resistances
