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The CP2 exam has 110 questions and runs 3 hours.
These 10 free CP2 questions are organized by exam domain, so you can see how each part of the Cathodic Protection 2 - Technician blueprint is tested. Reveal the answer and explanation under each question.
A coated steel pipe is accidentally bonded to a much larger bare copper grounding grid in moist soil. The pipe coating is intact except for a small holiday, and no CP current is being applied. What makes the exposed steel particularly vulnerable?
Correct answer: D - High anodic current density develops at the steel holiday.
At a dry-soil test point, a voltmeter reads -0.742 V with a 10 megohm input resistance and -0.806 V with a 100 megohm input resistance. Returning to 10 megohms restores a reading of -0.743 V. Reference-electrode position, lead connections, and CP output remain unchanged, and both settings pass a calibration check. What explains the repeatable change?
Correct answer: A - Loading of a high-resistance reference-electrode measurement circuit.
A buried steel pipeline is evaluated using the approved 100 mV polarization-decay criterion. With a stationary, verified saturated copper/copper-sulfate electrode, a technician records -1.190 V ON, -0.815 V immediately after the IR drop is removed, and -0.680 V at the end of the decay test. All contributing sources were interrupted, and the instant-OFF sample preceded appreciable depolarization. What result should be reported?
Correct answer: B - Meets the criterion: 135 mV of polarization decay.
The carrier pipe and casing at a road crossing both read -1.070 V versus the same fixed copper/copper-sulfate electrode. A contractor proposes a metallic-short repair because the two ON potentials match. Before that repair is specified, the CP technician should:
Correct answer: A - Compare controlled current responses and check for metallic bypass paths.
An AC current-attenuation survey identifies a pipeline segment with unusually high signal loss after branches and bonds have been accounted for. The next task is to pinpoint coating-current leakage locations along that segment. All contributing CP current sources can be interrupted, and surface access is available. Select the most direct follow-up method.
Correct answer: A - A DC voltage-gradient survey using synchronized pulsed current.
A manually tapped, single-phase full-wave CP rectifier normally delivers 28 V DC and 7 A. At the unchanged tap setting, calibrated measurements now show 34 V DC at the output terminals and less than 0.01 A in the output lead. The AC supply and transformer secondary voltage are normal. Which fault best fits this combination?
Correct answer: D - An open circuit in an anode lead or structure-return lead.
An acceptance check on a single-phase rectifier records 120 V RMS input, 5.0 A RMS input, a measured power factor of 0.80, and steady DC output of 24 V at 15 A. The owner flags efficiencies below 70% for investigation. Which entry belongs in the efficiency assessment?
Correct answer: B - 75% efficiency; this result does not trigger the owner's investigation threshold.
Packaged magnesium anodes match the purchase specification and pass receiving inspection. Each has an impermeable polyethylene shipping cover over an intact permeable bag of specified backfill. The approved installation procedure requires the backfill bag to remain with the buried anode. Which instruction should the foreman give before placement?
Correct answer: C - Remove the polyethylene cover and leave the permeable backfill bag intact.
A buried aluminum line is evaluated under the aluminum criteria in 49 CFR Part 192, Appendix D. Its verified IR-corrected potential is -1.310 V versus saturated copper/copper-sulfate, and the soil's natural pH is 8.7. No previous tests establish that this operating potential avoids appreciable corrosion in this environment. Which assessment is justified?
Correct answer: A - Investigate excessive cathodic polarization and alkaline attack before accepting this operating condition.
Before connecting test leads at a pipeline test station in a power-line corridor, a qualified technician measures 26 V RMS between the pipe and local earth. The CP rectifier is already off. The approved work plan prohibits contact work at 15 V RMS or higher. How should the crew proceed?
Correct answer: C - Suspend contact work and obtain the required AC hazard controls.
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