Page 1 of 164
COLLECTIONS SYSTEM MAINTENANCE
GRADE 3-STUDY GUIDE 2026|REAL EXAM
QUESTIONS AND ANSWERS|A+GRADE
ASSURED
1. Why are gasoline and volatile solvents objectionable when
present in a sewer?
A) They increase the biological oxygen demand
B) They produce an explosion hazard
C) They corrode concrete pipes
D) They generate hydrogen sulfide
Answer: B
Rationale: Gasoline and volatile solvents produce
flammable vapors that can accumulate in sewer
,Page 2 of 164
headspaces, creating a serious risk of fire or explosion
when combined with an ignition source. The vapors are
lighter than air and tend to collect in high points and
manholes.
2. You should never attempt to install, maintain, repair or replace
electrical equipment panels, controls, wiring or circuits unless:
A) You have been told to do so by a supervisor
B) You know what you are doing, are qualified and are
authorized
C) The power has been turned off at the main breaker
D) A second person is present as a safety observer
Answer: B
Rationale: Working on electrical equipment requires
specific training, qualification, and employer authorization.
Without these, the worker places themselves and others at
,Page 3 of 164
risk of electrocution, arc flash, or equipment damage, and
may violate OSHA regulations.
3. When working in confined spaces or sewers, what form of
lighting would you use?
A) Mirrors to direct sunlight or explosion-proof lighting
B) Ordinary electric lights with standard bulbs
C) Propane, gas or kerosene lanterns
D) Battery-operated headlamps only
Answer: A
Rationale: In confined spaces where explosive gases may
be present, only intrinsically safe or explosion-proof lighting
must be used to prevent ignition. Mirrors directing sunlight
are a historical alternative when electrical lighting cannot
be safely deployed.
, Page 4 of 164
4. What can happen if water-based substances are used to
extinguish electrical fires?
A) Nothing – water is effective on all fires
B) The fumes are not harmful
C) Receive an electrical shock
D) They will corrode the electrical contacts
Answer: C
Rationale: Water conducts electricity. Applying water to an
electrical fire creates a path for current to flow through the
water stream back to the operator, causing severe electrical
shock or electrocution.
5. When testing a manhole for explosive gases, when should the
first tests be made?
A) After removing the manhole cover
B) Before removing the manhole cover
COLLECTIONS SYSTEM MAINTENANCE
GRADE 3-STUDY GUIDE 2026|REAL EXAM
QUESTIONS AND ANSWERS|A+GRADE
ASSURED
1. Why are gasoline and volatile solvents objectionable when
present in a sewer?
A) They increase the biological oxygen demand
B) They produce an explosion hazard
C) They corrode concrete pipes
D) They generate hydrogen sulfide
Answer: B
Rationale: Gasoline and volatile solvents produce
flammable vapors that can accumulate in sewer
,Page 2 of 164
headspaces, creating a serious risk of fire or explosion
when combined with an ignition source. The vapors are
lighter than air and tend to collect in high points and
manholes.
2. You should never attempt to install, maintain, repair or replace
electrical equipment panels, controls, wiring or circuits unless:
A) You have been told to do so by a supervisor
B) You know what you are doing, are qualified and are
authorized
C) The power has been turned off at the main breaker
D) A second person is present as a safety observer
Answer: B
Rationale: Working on electrical equipment requires
specific training, qualification, and employer authorization.
Without these, the worker places themselves and others at
,Page 3 of 164
risk of electrocution, arc flash, or equipment damage, and
may violate OSHA regulations.
3. When working in confined spaces or sewers, what form of
lighting would you use?
A) Mirrors to direct sunlight or explosion-proof lighting
B) Ordinary electric lights with standard bulbs
C) Propane, gas or kerosene lanterns
D) Battery-operated headlamps only
Answer: A
Rationale: In confined spaces where explosive gases may
be present, only intrinsically safe or explosion-proof lighting
must be used to prevent ignition. Mirrors directing sunlight
are a historical alternative when electrical lighting cannot
be safely deployed.
, Page 4 of 164
4. What can happen if water-based substances are used to
extinguish electrical fires?
A) Nothing – water is effective on all fires
B) The fumes are not harmful
C) Receive an electrical shock
D) They will corrode the electrical contacts
Answer: C
Rationale: Water conducts electricity. Applying water to an
electrical fire creates a path for current to flow through the
water stream back to the operator, causing severe electrical
shock or electrocution.
5. When testing a manhole for explosive gases, when should the
first tests be made?
A) After removing the manhole cover
B) Before removing the manhole cover
