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CME Motors, Controls & Industrial Wiring Flashcards

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

Read the first 6 CME Motors, Controls & Industrial Wiring flashcards as text

  1. Per NEC 501.10(A), what wiring methods are permitted in Class I, Division 1 hazardous locations?

    Answer: Threaded rigid metal conduit (RMC) or threaded steel intermediate metal conduit (IMC)

    NEC 501.10(A) requires threaded RMC or IMC in Class I Division 1 locations to maintain conduit system integrity and prevent ignition of flammable gases.

  2. What is the function of a conduit seal (sealing fitting) installed in a hazardous location per NEC 501.15?

    Answer: Prevent flame or explosion from propagating through the conduit system between hazardous and non-hazardous areas

    Conduit seals filled with approved compound prevent ignited gases inside an enclosure from traveling through the conduit and igniting gases in adjacent areas.

  3. Which NEC article covers the electrical installation requirements for industrial machinery?

    Answer: NEC Article 670

    NEC Article 670 covers industrial machinery, defining supply conductor sizing, disconnecting means, and overcurrent protection for machine tools and similar equipment.

  4. When sizing the supply conductors for an industrial machine per NEC 670.4(A), what is the minimum ampacity required relative to the machine's full-load current rating?

    Answer: 125% of the machine's full-load current rating

    NEC 670.4(A) requires supply conductors for industrial machinery to be sized at not less than 125% of the machine's nameplate full-load current.

  5. What safety function does a Category 3 safety relay provide in a machine control system per ISO 13849?

    Answer: A fault in any single component will not lead to loss of the safety function and the fault is detected

    ISO 13849 Category 3 requires that a single fault does not cause loss of safety function, and the fault must be detected at or before the next safety demand.

  6. Per NEC 110.26(C)(2), what is the minimum headroom required for electrical equipment rated 1,200A or more that is over 6 ft wide?

    Answer: 6.5 ft (2.0 m)

    NEC 110.26(C)(2) requires a minimum headroom of 6.5 ft for service equipment, switchboards, or panelboards rated 1,200A or more that exceed 6 ft in width.