Reference Electrode Practice Questions

These questions test reference electrode use, reporting, placement, and interpretation in cathodic protection testing.

Study Focus

Focus on reference electrode type, placement, condition, reporting, permanent reference cell reliability, and why readings on different reference scales are not interchangeable.

Practice Questions

  1. What is the purpose of a reference electrode in CP testing?

    1. To provide a stable comparison point for potential measurements
    2. To discharge CP current into the soil
    3. To convert AC to DC
    4. To replace the protected structure lead

    Answer: A. A reference electrode provides a stable comparison point for potential measurements.

  2. Which reference electrode is commonly used for buried steel in soil?

    1. Silver-silver chloride
    2. Copper-copper sulfate
    3. Dry wood electrode
    4. Thermocouple only

    Answer: B. CSE is commonly used for buried steel in soil.

  3. Which reference electrode is commonly used in seawater?

    1. Silver-silver chloride
    2. Dry copper wire only
    3. Paint probe
    4. Insulating flange kit

    Answer: A. Silver-silver chloride reference electrodes are commonly used in seawater.

  4. Why is “−860 mV” incomplete by itself?

    1. It does not identify the reference electrode or test condition
    2. It is always AC
    3. It proves all structures are protected
    4. It means no electrolyte exists

    Answer: A. A potential value must identify the reference electrode and test condition.

  5. Why can poor reference electrode placement cause misleading readings?

    1. The electrode may not represent the electrolyte near the structure being evaluated
    2. Placement never matters
    3. Reference electrodes only measure pipe wall thickness
    4. Reference electrodes supply AC power

    Answer: A. Placement affects what the reading represents.

  6. Which condition can make a portable reference electrode unreliable?

    1. Contamination, poor contact, drying, or damage
    2. Correct placement
    3. Proper documentation
    4. Stable contact with electrolyte

    Answer: A. Electrode condition affects measurement reliability.

  7. Why should permanent reference cells be reviewed critically?

    1. They can drift, fail, dry out, or lose reliable contact
    2. They never fail
    3. They eliminate all survey requirements
    4. They are not affected by installation conditions

    Answer: A. Permanent reference electrodes can become unreliable.

  8. Can CSE, silver-silver chloride, and zinc readings be treated as identical?

    1. No, they use different reference scales
    2. Yes, all reference electrodes have the same potential
    3. Yes, if the rectifier is off
    4. Yes, for all structures and environments

    Answer: A. Different reference electrodes are not numerically interchangeable without proper interpretation.

  9. What should be included when reporting a CP potential?

    1. Value, polarity, reference electrode, location, and test condition
    2. Only the number
    3. Only the weather
    4. Only the pipe color

    Answer: A. The reading must be reported with enough context to interpret it.

  10. Why can a failed fixed reference cell create a false CP conclusion?

    1. It may report potentials that do not represent the actual structure condition
    2. It always improves accuracy
    3. It repairs coating holidays
    4. It increases anode mass

    Answer: A. Bad reference data can make CP appear better or worse than it is.

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