NACE CP1 Practical Exam 2026/2027 • Cathodic Protection Level 1 • Unofficial Study Aid
NACE CP1 – Exam 2026/2027 – Complete Practice Questions
& Answers
National Association of Corrosion Engineers (NACE) – now AMPP — Cathodic Protection Level 1 (CP1) • 90
Practice Questions with Rationales
IMPORTANT DISCLAIMER: This is an independent, original PRACTICE exam aligned to current NACE/AMPP CP1 standards and cathodic
protection principles for 2026/2027. It is NOT affiliated with, endorsed by, or sourced from NACE/AMPP, and does NOT contain actual
NACE/AMPP exam questions. Use solely for study and self-assessment. Always verify current NACE/AMPP standards (e.g., SP0169,
SP0285, TM0101) from official sources.
The NACE/AMPP CP1 Cathodic Protection Level 1 exam validates foundational competence in corrosion and
cathodic protection for buried and submerged structures. This practice exam mirrors 2026/2027 CP1
content, covering corrosion fundamentals, galvanic and impressed current systems, testing equipment,
criteria, interference, safety, and documentation to focus your practical review.
Instructions: Select the best answer for each scenario. The correct answer is highlighted in bold cyan. Each rationale cites
the relevant NACE/AMPP standard, CP principle, or industry practice and explains why distractors are incorrect. Simulate
CP1 exam conditions and review rationales thoroughly.
Section 1: Introduction
Section 2: The Complete Exam
Domains covered: Corrosion Fundamentals • Cathodic Protection Principles • Testing Equipment & Techniques • Galvanic Anodes •
Impressed Current Systems • Galvanic vs Impressed Current • Pipeline & Tank Protection • Interference • Safety • Documentation &
Record Keeping | Time: Simulate 3–4 hours | Guidance: Review rationales citing NACE/AMPP/ SP0169/SP0285/ SP0177, not just
scores.
1. A corrosion cell requires which four components to function?
A. Only anode and cathode
B. Only electrolyte
C. Only coating
D. Anode, cathode, electrolyte, and metallic/electronic path
Rationale: All four elements must be present for electrochemical corrosion; eliminating any one
stops the reaction. Partial lists or coating alone are incomplete per NACE CP theory.
2. At the anode, which reaction occurs?
A. Reduction: O₂ + 2H₂O + 4e⁻ → 4OH⁻
B. No reaction
C. Only hydrogen evolution always
D. Oxidation: Fe → Fe²⁺ + 2e⁻ (metal dissolution)
Rationale: The anode oxidizes and dissolves, releasing electrons. The oxygen/water reduction occurs
at the cathode; confusing anode/cathode reverses the cell. Hydrogen evolution dominates only in
acidic/deaerated conditions.
Confidential Study Use Only — Not Affiliated with or Endorsed by NACE/AMPP — Does Not Contain Actual Exam Content — Verify Current Standards
, NACE CP1 Practical Exam 2026/2027 • Cathodic Protection Level 1 • Unofficial Study Aid
3. In neutral aerated soil/water, the predominant cathodic reaction for steel is:
A. Fe → Fe²⁺
B. O₂ + 2H₂O + 4e⁻ → 4OH⁻ (oxygen reduction)
C. 2H⁺ + 2e⁻ → H₂ always
D. Zn → Zn²⁺
Rationale: In aerated neutral environments, oxygen reduction is the cathodic reaction. Iron
dissolution is anodic, hydrogen evolution dominates in acidic/low-pH, and zinc is for galvanic
anodes.
4. Galvanic corrosion occurs when:
A. Identical metals isolated
B. Only coating present
C. Dissimilar metals are electrically connected in a common electrolyte and the more
active metal becomes the anode
D. No electrolyte present
Rationale: Galvanic requires dissimilar metals + electrical connection + electrolyte; the more active
(more negative) corrodes preferentially. Identical/isolation/no electrolyte negate the cell.
5. Mill scale on pipeline steel is:
A. Same potential as steel
B. Cathodic to steel; holidays drive rapid pitting of exposed steel and must be removed
C. Inert and harmless
D. Anodic and protective
Rationale: Mill scale is cathodic to steel, creating a strong galvanic couple at defects, accelerating
anodic dissolution of steel. It must be removed per surface prep standards.
6. Crevice corrosion is driven by:
A. Only coating thickness
B. Uniform oxygen everywhere
C. Only high temperature
D. Differential aeration/oxygen concentration and restricted mass transfer inside the
crevice making it anodic
Rationale: Crevice geometry creates a differential aeration cell and ion concentration differences,
making the crevice anodic. Uniform oxygen or coating thickness alone does not explain the
mechanism.
7. Pitting corrosion is especially hazardous because:
A. It is uniform and easily measured by weight loss
B. It causes deep localized penetration with minimal weight loss, leading to leaks with
little warning
Confidential Study Use Only — Not Affiliated with or Endorsed by NACE/AMPP — Does Not Contain Actual Exam Content — Verify Current Standards
, NACE CP1 Practical Exam 2026/2027 • Cathodic Protection Level 1 • Unofficial Study Aid
C. It increases wall thickness
D. It only affects color
Rationale: Pitting's localization means weight loss underestimates damage; perforation occurs
quickly. Uniform/color/thickness increase mischaracterize the risk.
8. The galvanic series in seawater shows which metal is most active (most anodic)?
A. Steel most active
B. Magnesium (-1.6 V vs CSE) more active than zinc, aluminum, steel, copper
C. Titanium most active
D. Copper most active
Rationale: In the seawater galvanic series, Mg is most active/negative, then Zn, Al, mild steel, then
noble metals like Cu. Reversing the series misapplies sacrificial anode selection.
9. Passivation of stainless steel depends on:
A. Thin adherent chromium oxide film that reforms with oxygen; chlorides break it down
B. Thick rust layer
C. Zinc coating
D. No film at all
Rationale: Stainless relies on Cr₂O₃ passive film; chloride breaks it, causing pitting. Thick rust or zinc
describes carbon steel corrosion products or coatings, not passivation.
10. Cathodic protection protects steel by:
A. Removing electrolyte completely
B. Making structure an anode
C. Making the entire structure a cathode, suppressing anodic dissolution via supplied
electrons
D. Only adding coating
Rationale: CP supplies electrons so the structure is cathodic; oxidation is suppressed.
Anodic/impossible electrolyte removal only or coating alone without CP is not CP protection.
11. A galvanic (sacrificial anode) system works by:
A. A more active metal (Mg/Zn/Al) corrodes preferentially, delivering current through
electrolyte to protect steel
B. Only barrier
C. No current needed
D. Impressed current from rectifier only
Rationale: Galvanic systems rely on natural potential difference between active anode and steel, no
external power. Rectifier is impressed current, not galvanic.
Confidential Study Use Only — Not Affiliated with or Endorsed by NACE/AMPP — Does Not Contain Actual Exam Content — Verify Current Standards
NACE CP1 – Exam 2026/2027 – Complete Practice Questions
& Answers
National Association of Corrosion Engineers (NACE) – now AMPP — Cathodic Protection Level 1 (CP1) • 90
Practice Questions with Rationales
IMPORTANT DISCLAIMER: This is an independent, original PRACTICE exam aligned to current NACE/AMPP CP1 standards and cathodic
protection principles for 2026/2027. It is NOT affiliated with, endorsed by, or sourced from NACE/AMPP, and does NOT contain actual
NACE/AMPP exam questions. Use solely for study and self-assessment. Always verify current NACE/AMPP standards (e.g., SP0169,
SP0285, TM0101) from official sources.
The NACE/AMPP CP1 Cathodic Protection Level 1 exam validates foundational competence in corrosion and
cathodic protection for buried and submerged structures. This practice exam mirrors 2026/2027 CP1
content, covering corrosion fundamentals, galvanic and impressed current systems, testing equipment,
criteria, interference, safety, and documentation to focus your practical review.
Instructions: Select the best answer for each scenario. The correct answer is highlighted in bold cyan. Each rationale cites
the relevant NACE/AMPP standard, CP principle, or industry practice and explains why distractors are incorrect. Simulate
CP1 exam conditions and review rationales thoroughly.
Section 1: Introduction
Section 2: The Complete Exam
Domains covered: Corrosion Fundamentals • Cathodic Protection Principles • Testing Equipment & Techniques • Galvanic Anodes •
Impressed Current Systems • Galvanic vs Impressed Current • Pipeline & Tank Protection • Interference • Safety • Documentation &
Record Keeping | Time: Simulate 3–4 hours | Guidance: Review rationales citing NACE/AMPP/ SP0169/SP0285/ SP0177, not just
scores.
1. A corrosion cell requires which four components to function?
A. Only anode and cathode
B. Only electrolyte
C. Only coating
D. Anode, cathode, electrolyte, and metallic/electronic path
Rationale: All four elements must be present for electrochemical corrosion; eliminating any one
stops the reaction. Partial lists or coating alone are incomplete per NACE CP theory.
2. At the anode, which reaction occurs?
A. Reduction: O₂ + 2H₂O + 4e⁻ → 4OH⁻
B. No reaction
C. Only hydrogen evolution always
D. Oxidation: Fe → Fe²⁺ + 2e⁻ (metal dissolution)
Rationale: The anode oxidizes and dissolves, releasing electrons. The oxygen/water reduction occurs
at the cathode; confusing anode/cathode reverses the cell. Hydrogen evolution dominates only in
acidic/deaerated conditions.
Confidential Study Use Only — Not Affiliated with or Endorsed by NACE/AMPP — Does Not Contain Actual Exam Content — Verify Current Standards
, NACE CP1 Practical Exam 2026/2027 • Cathodic Protection Level 1 • Unofficial Study Aid
3. In neutral aerated soil/water, the predominant cathodic reaction for steel is:
A. Fe → Fe²⁺
B. O₂ + 2H₂O + 4e⁻ → 4OH⁻ (oxygen reduction)
C. 2H⁺ + 2e⁻ → H₂ always
D. Zn → Zn²⁺
Rationale: In aerated neutral environments, oxygen reduction is the cathodic reaction. Iron
dissolution is anodic, hydrogen evolution dominates in acidic/low-pH, and zinc is for galvanic
anodes.
4. Galvanic corrosion occurs when:
A. Identical metals isolated
B. Only coating present
C. Dissimilar metals are electrically connected in a common electrolyte and the more
active metal becomes the anode
D. No electrolyte present
Rationale: Galvanic requires dissimilar metals + electrical connection + electrolyte; the more active
(more negative) corrodes preferentially. Identical/isolation/no electrolyte negate the cell.
5. Mill scale on pipeline steel is:
A. Same potential as steel
B. Cathodic to steel; holidays drive rapid pitting of exposed steel and must be removed
C. Inert and harmless
D. Anodic and protective
Rationale: Mill scale is cathodic to steel, creating a strong galvanic couple at defects, accelerating
anodic dissolution of steel. It must be removed per surface prep standards.
6. Crevice corrosion is driven by:
A. Only coating thickness
B. Uniform oxygen everywhere
C. Only high temperature
D. Differential aeration/oxygen concentration and restricted mass transfer inside the
crevice making it anodic
Rationale: Crevice geometry creates a differential aeration cell and ion concentration differences,
making the crevice anodic. Uniform oxygen or coating thickness alone does not explain the
mechanism.
7. Pitting corrosion is especially hazardous because:
A. It is uniform and easily measured by weight loss
B. It causes deep localized penetration with minimal weight loss, leading to leaks with
little warning
Confidential Study Use Only — Not Affiliated with or Endorsed by NACE/AMPP — Does Not Contain Actual Exam Content — Verify Current Standards
, NACE CP1 Practical Exam 2026/2027 • Cathodic Protection Level 1 • Unofficial Study Aid
C. It increases wall thickness
D. It only affects color
Rationale: Pitting's localization means weight loss underestimates damage; perforation occurs
quickly. Uniform/color/thickness increase mischaracterize the risk.
8. The galvanic series in seawater shows which metal is most active (most anodic)?
A. Steel most active
B. Magnesium (-1.6 V vs CSE) more active than zinc, aluminum, steel, copper
C. Titanium most active
D. Copper most active
Rationale: In the seawater galvanic series, Mg is most active/negative, then Zn, Al, mild steel, then
noble metals like Cu. Reversing the series misapplies sacrificial anode selection.
9. Passivation of stainless steel depends on:
A. Thin adherent chromium oxide film that reforms with oxygen; chlorides break it down
B. Thick rust layer
C. Zinc coating
D. No film at all
Rationale: Stainless relies on Cr₂O₃ passive film; chloride breaks it, causing pitting. Thick rust or zinc
describes carbon steel corrosion products or coatings, not passivation.
10. Cathodic protection protects steel by:
A. Removing electrolyte completely
B. Making structure an anode
C. Making the entire structure a cathode, suppressing anodic dissolution via supplied
electrons
D. Only adding coating
Rationale: CP supplies electrons so the structure is cathodic; oxidation is suppressed.
Anodic/impossible electrolyte removal only or coating alone without CP is not CP protection.
11. A galvanic (sacrificial anode) system works by:
A. A more active metal (Mg/Zn/Al) corrodes preferentially, delivering current through
electrolyte to protect steel
B. Only barrier
C. No current needed
D. Impressed current from rectifier only
Rationale: Galvanic systems rely on natural potential difference between active anode and steel, no
external power. Rectifier is impressed current, not galvanic.
Confidential Study Use Only — Not Affiliated with or Endorsed by NACE/AMPP — Does Not Contain Actual Exam Content — Verify Current Standards
