Deck 39: High Voltage Electricity

Question 1

What does the NEC consider to be the upper safe limit of electrical current that the average human body can sustain?

A) 50 mA
B) 10mA
C) 5mA
D) 2mA

Answer 1

5mA

Question 2

Which of the following voltage values is generally considered to fall under the definition of a high voltage circuit?

A) 600 volts or higher
B) 110 volts or higher
C) 50 volts or higher
D) 12.6 volts or higher

Answer 2

50 volts or higher

Question 3

When a person is electrocuted, which of the following best describes his/her physical condition?

A) The person has received an electric shock.
B) The person has been injured by an electric shock.
C) The person is dead.
D) All of the above.

Answer 3

The person is dead.

Question 4

What is said to be responsible for most deaths by electricity in the United States?

A) Lightning strikes
B) Workers trained in electricity, short-cutting basic safety procedures
C) House owners undertaking repairs on electrical equipment
D) Service technicians not wearing appropriate footwear

Question 5

Technician A says that a hydrogen fuel cell powertrain contains HV circuits. Technician B says that a hybrid electric powertrain contains HV circuits. Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 6

What CAT designation does a household refrigerator cleaner fall under?

A) CAT I
B) CAT II
C) CAT III
D) CAT IV

Question 7

What CAT designation is applied to grid electrical voltages?

A) CAT I
B) CAT II
C) CAT III
D) CAT IV

Question 8

When working on HV vehicle electrical systems what minimum category of tooling and PPE protection gear should be used?

A) CAT I
B) CAT II
C) CAT III
D) CAT IV

Question 9

What MUST be displayed on footwear tested and certified for use on HV vehicle electrical systems?

A) An orange omega symbol
B) A green UL certification symbol
C) A steel toe
D) All of the above

Question 10

When working on HV circuits, what is the reason for working one-handed and keeping one hand in a pocket behind your back?

A) The back pocket of a pair of coveralls is a good ground point.
B) In the event of a HV shock, it minimizes the chance of the current passing through the heart.
C) The spare hand can be used to grab an iron safety rail in the event of an electric shock.
D) If one hand gets burned off, you'll still have one good hanD.

Question 11

Which of the following is the best reason to always wear CAT III PPE when working on HV vehicle systems even after the electrical circuits have been tested to be neutral?

A) Lighting might strike the vehicle
B) Distributed capacitance
C) A thermal runway event could occur
D) It impresses supervisors

Question 12

What is ventricular fibrillation?

A) a heart murmur
B) the result of an electrical shock that stops a heart from beating
C) a medical tool designed to reactivate a heart that has stopped beating
D) the consequence of an electrical short circuit

Question 13

What does the acronym AED spell out to in the context of a shop repairing HV vehicles?

A) Automated external defibrillator
B) Alternating current discharge
C) Accidental electrical discharge
D) Automatic eddy dissipation

Question 14

For what purpose is an AED used?

A) energizing a dead battery cell
B) heart bypass surgery
C) heart defibrillation
D) heart fibrillation

Question 15

What is the most common root cause of a thermal runaway event in a li-ion battery?

A) deficit of electrolyte in a cell
B) exposure to external high temperatures
C) breakdown of the battery bank cooling system
D) manufacturing defect in the cell chemistry of a single cell

Question 16

Technician A says that arc blast can be deadly because it releases massive amounts of electrical energy that can vaporize metals. Technician B says that an arc flash event is relatively harmless because electrical energy is released mainly as light. Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 17

Technician A says that it is safe to hose down LV batteries using a steam washer. Technician B says that it is safe to clean LV batteries with a power washer providing the wand nozzle remains at least 6 feet (2 meters) away from the batteries. Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 18

Technician A uses shop air pressure regulated at 75 psi (500 kPa) to clean HV battery packs. Technician B cleans li-ion battery banks using a power washer but makes sure the wand is not brought closer than 6 feet (2 meters) from the orange bank terminals. Who is correct?

A) Technician A Only
B) Technician B Only
C) Both A and B
D) Neither A nor B

Question 19

Which of the following is the appropriate hand protection when working with HV circuits?

A) Class E rated gloves.
B) Class 0 rated gloves.
C) Corrosive-protected rubber gloves.
D) Uncured cowhide welding gloves.

Question 20

How does the CEV battery management system (BMS) respond when it detects an overheated li-ion cell?

A) Increases coolant flow around the cell jacket
B) Shorts out the overheating cell
C) Deletes the overheating cell
D) Rests the overheating cell

Question 21

When selecting a wrench to work on an HV electrical component, which of the following specifications should be correct?

A) Insulated, and CAT III rated
B) Insulated, and UL certified
C) ASTM certified
D) OSHA certified