Practice Test Geeks(EVT) Certified Electric Vehicle Technician Practice Test
← All EVT Flashcard Decks

High Voltage Electrical Systems & Wiring Flashcards

7 cards from real EVT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 High Voltage Electrical Systems & Wiring flashcards as text

  1. What is the standard color code for high-voltage wiring in electric vehicles according to SAE and FMVSS 305 standards?

    Answer: Orange

    SAE and FMVSS 305 standards require high-voltage wiring in electric vehicles to use an orange outer jacket to identify HV cables and warn technicians.

  2. At what minimum DC voltage level are electric vehicle systems generally classified as 'high voltage' under FMVSS 305?

    Answer: 60V DC

    FMVSS 305 and international safety standards classify any voltage above 60V DC (or 30V AC) as high voltage requiring special precautions.

  3. What is the primary purpose of the manual service disconnect (MSD) in an EV high-voltage system?

    Answer: To physically interrupt the HV circuit for safe servicing

    The MSD physically breaks the HV circuit, de-energizing the system and allowing technicians to safely service HV components.

  4. What is the purpose of the precharge circuit in a high-voltage EV system?

    Answer: To slowly charge large capacitors before main contactors close, limiting inrush current

    The precharge circuit limits inrush current by slowly charging inverter and DC/DC capacitors through a resistor before the main contactors close, preventing arcing and component damage.

  5. What minimum rubber insulating glove class is required when working on EV high-voltage systems operating up to 1000V?

    Answer: Class 0 (1000V rated)

    Class 0 rubber insulating gloves are rated for use on systems up to 1000V, making them the minimum class required for most EV high-voltage work.

  6. Which instrument must be used to verify the absence of high voltage before touching HV components after removing the MSD?

    Answer: A CAT III or CAT IV rated digital multimeter

    A CAT III or CAT IV rated digital multimeter is required because it is designed to withstand voltage transients present in high-voltage environments without failing dangerously.

  7. What is the minimum isolation resistance required per volt between the HV bus and vehicle chassis under FMVSS 305?

    Answer: 100 ohms per volt

    FMVSS 305 requires a minimum isolation resistance of 100 ohms per volt between the HV bus and vehicle chassis to protect occupants from electric shock.