CSLB Class A — General Engineering (Trade Exam) — All Questions

What is the purpose of removing the pressure source during a Method A test?

• a.So the test shows what the pipe holds on its own✓
• b.So the pump can cool down between the test periods
• c.So the line can be flushed out before the next test
• d.So air can be added to the line before the next test

The source of pressure is removed and the line left under the required pressure, so any leak shows as a drop on the gauge. Not "So the pump can cool down between the test periods": pump temperature is not the reason. Not "So air can be added to the line before the next test": air is not added. Not "So the line can be flushed out before the next test": flushing is a separate step.Caltrans Standard Specifications (2025) 20-2.01A(4)(b)(ii)

Who must certify each backflow preventer assembly on Caltrans work?

• a.The pipe supplier's sales representative, if the brand is listed in the submittal
• b.The soils engineer, who also certifies the pipe bedding and compaction
• c.A licensed electrician who is working on the irrigation controller
• d.A tester whose credential is current with the water purveyor✓

Each assembly must be certified by a tester with active and valid certification from the water purveyor having jurisdiction. Not "A licensed electrician who is working on the irrigation controller": electrical licenses are not the qualification. Not "The pipe supplier's sales representative, if the brand is listed in the submittal": certification comes from the purveyor or AWWA. Not "The soils engineer, who also certifies the pipe bedding and compaction": soils engineers do not certify backflow assemblies.Caltrans Standard Specifications (2025) 20-2.02A(4)

What is a backflow preventer assembly installed to prevent?

• a.System water flowing back into the public supply✓
• b.Loss of pressure at the end of the line during peak use
• c.Water hammer in the main
• d.Frost damage to the pipe during a winter shutdown of the system

A backflow preventer keeps water in a connected system from flowing back into the potable supply. Not "Water hammer in the main": surge protection is a different device. Not "Frost damage to the pipe during a winter shutdown of the system": insulation or depth handles frost. Not "Loss of pressure at the end of the line during peak use": pressure loss is not what the assembly stops.Caltrans Standard Specifications (2025) 20-2.02

Which Method B test condition applies to the upstream portion of a supply line before backfilling?

• a.Pressure held for 5 minutes with the valves closed and the gauge on the line
• b.Full water pressure held for not less than 8 consecutive hours after air is expelled✓
• c.A visual check, made after the trench is opened up
• d.Pressure of 125 psi held for 1 hour, then released at once

Method B maintains full pressure from the source for not less than 8 consecutive hours after air is expelled. Not "Pressure held for 5 minutes with the valves closed and the gauge on the line": far shorter than the stated period. Not "A visual check, made after the trench is opened up": Method B requires a timed full-pressure test. Not "Pressure of 125 psi held for 1 hour, then released at once": that describes Method A.Caltrans Standard Specifications (2025) 20-2.01A(4)(b)(iii)

Where does Caltrans require a thrust block on an irrigation main supply line?

• a.At each change in direction, at the terminus run and at other locations shown✓
• b.Nowhere on plastic pipe, which flexes and holds itself in place
• c.After the pressure test is finished and the line is backfilled
• d.On straight runs under 100 feet that have no fittings at all

A thrust block is installed at each change in direction on the main supply line, terminus run and other locations shown. Not "On straight runs under 100 feet that have no fittings at all": straight runs do not push outward on a fitting. Not "Nowhere on plastic pipe, which flexes and holds itself in place": pressure pushes outward at bends whatever the pipe material. Not "After the pressure test is finished and the line is backfilled": anchorage must resist thrust during testing.Caltrans Standard Specifications (2025) 20-2.08C(1)

A conduit trench is backfilled under Caltrans section 87-1.03. What goes directly under the conduit?

• a.Nothing, since conduit sits on native soil
• b.12 inches of rock under the conduit
• c.A layer of bare clay
• d.A minimum of 2 inches of sand bedding✓

Trench backfill begins with a minimum of 2 inches of sand bedding before installing the conduit. Not "A layer of bare clay": clay does not give uniform bedding. Not "12 inches of rock under the conduit": the specification calls for sand bedding. Not "Nothing, since conduit sits on native soil": the specification requires bedding.Caltrans Standard Specifications (2025) 87-1.03B(3)(b)(i)

How much slurry concrete goes over a conduit in that trench detail?

• a.6 inches
• b.5 feet
• c.18 inches✓
• d.2 inches

The detail is 18 inches of slurry concrete over the conduit, then native material. Not "2 inches": that is the sand bedding. Not "6 inches": that is the depth of the warning tape below grade. Not "5 feet": far more than the detail calls for.Caltrans Standard Specifications (2025) 87-1.03B(3)(b)(i)

What minimum bend radius applies to HDPE conduit sweeps on Caltrans electrical work?

• a.100 times the inside diameter of the conduit
• b.1 times the outside diameter of the conduit
• c.10 times the outside diameter of the conduit✓
• d.A fixed 2 inches for the conduit

Sweeps maintain a bend radius of a minimum of 10 times the outside diameter. Not "1 times the outside diameter of the conduit": a tight bend damages cable on pulling. Not "A fixed 2 inches for the conduit": radius depends on the conduit size. Not "100 times the inside diameter of the conduit": a far larger radius than the specification asks.Caltrans Standard Specifications (2025) 87-1.03B(3)(b)(ii)

How many degrees of bends may a conduit run have between pull points under the Caltrans electrical specification?

• a.As many as needed
• b.No more than 360 degrees✓
• c.No more than 720 degrees
• d.No more than 90 degrees

The number of bends in a conduit run is limited to no more than 360 degrees between pull points. Not "No more than 90 degrees": the limit is larger than a single bend. Not "As many as needed": the number of bends is limited. Not "No more than 720 degrees": this exceeds the stated total.Caltrans Standard Specifications (2025) 87-1.03B(1)

An existing Caltrans underground facility lies within 2 feet of a planned excavation. What must be done before power equipment is used?

• a.Use a backhoe carefully with a spotter watching
• b.Assume it lies 5 feet deeper than the plan shows
• c.Determine its exact location by hand excavation✓
• d.Skip locating it if it is not marked on the site plans

If an existing facility is within 2 feet of an excavation, the exact location is determined by hand tools before power-operated equipment is used. Not "Use a backhoe carefully with a spotter watching": power equipment is not allowed first inside the zone. Not "Assume it lies 5 feet deeper than the plan shows": assumptions are not a substitute for locating it. Not "Skip locating it if it is not marked on the site plans": the facility shown must be located.Caltrans Standard Specifications (2025) 87-1.03A

Where must an existing Caltrans underground facility shown within 10 feet of an excavation be dealt with first?

• a.Located and field marked before work that could damage it✓
• b.Removed before the excavation starts by the crew
• c.Ignored if the plans lack its depth, since it cannot be located
• d.Painted pink by the crew, to show that it was found and logged

The contractor locates and field marks such a facility before performing work that could damage or interfere with it. Not "Removed before the excavation starts by the crew": removal is not required. Not "Ignored if the plans lack its depth, since it cannot be located": the plan's omission does not waive locating it. Not "Painted pink by the crew, to show that it was found and logged": locating is done before work, not by arbitrary marking.Caltrans Standard Specifications (2025) 87-1.03A

Irrigation conduit is run under a new pavement on Caltrans work. How far must it extend past the paving?

• a.2 feet beyond all paving, with unused ends capped✓
• b.It must stop 2 feet short of the paving
• c.Flush with the paving edge, with the ends left open
• d.20 feet beyond the paving, on both sides

The specification says to extend conduit 2 feet beyond all paving and cap the ends of unused conduit. Not "Flush with the paving edge, with the ends left open": future connections would require cutting new pavement. Not "20 feet beyond the paving, on both sides": more than the specification asks. Not "It must stop 2 feet short of the paving": this is backward.Caltrans Standard Specifications (2025) 20-2.07C(1)

For Caltrans electrical conduits, how far may conduit protrude inside a pull box or vault?

• a.No more than 2 inches✓
• b.No limit on how far it may protrude
• c.Exactly 12 inches past the wall
• d.At least 2 feet past the wall

Conduits must not protrude more than 2 inches inside the pull boxes and vaults. Not "At least 2 feet past the wall": conduit would block the box. Not "No limit on how far it may protrude": a limit is stated. Not "Exactly 12 inches past the wall": a larger figure than allowed.Caltrans Standard Specifications (2025) 87-1.03B(3)(b)(ii)