Oregon Contractor License Exam — All Questions

Under OSHA construction standards, at what height above a lower level does fall protection generally become required for workers on a construction site?

• a.2 feet
• b.4 feet
• c.6 feet✓
• d.20 feet

OSHA's construction fall-protection rule (29 CFR 1926.501) generally requires protection — such as guardrails, safety nets, or personal fall-arrest systems — when a worker is exposed to a fall of 6 feet or more to a lower level. (Note the general-industry trigger is 4 feet, but on construction sites the 6-foot rule applies.) Falls are consistently a leading cause of construction fatalities, which is why this threshold is heavily tested and enforced.

According to the hierarchy of controls, which method of protecting workers from a hazard is MOST effective and should be considered first?

• a.Eliminating the hazard entirely✓
• b.Providing personal protective equipment (PPE)
• c.Posting a warning sign
• d.Writing the hazard into a safety manual

The hierarchy of controls ranks protections from most to least effective: elimination, substitution, engineering controls, administrative controls, and finally PPE. Removing the hazard entirely is best because it does not depend on worker behavior or equipment holding up. PPE is the last line of defense — it only reduces exposure and relies on correct, consistent use, so it is the least reliable control on its own.

OSHA requires that a trench or excavation be protected by sloping, shoring, or a protective (trench) box once it reaches what depth?

• a.3 feet
• b.5 feet✓
• c.10 feet
• d.15 feet

Under OSHA's excavation standard (29 CFR 1926.652), a protective system — sloping/benching, shoring, or a trench box (shield) — is generally required for trenches 5 feet deep or greater (unless the excavation is entirely in stable rock). A registered professional engineer must design protection for trenches deeper than 20 feet. Cave-ins are frequently fatal, so a competent person must inspect excavations daily.

Who is responsible for providing a safe workplace and requiring the use of appropriate personal protective equipment on a job site?

• a.Each individual worker
• b.The equipment manufacturer
• c.The OSHA area office
• d.The employer✓

Under the OSH Act's General Duty Clause and OSHA standards, the employer has the primary legal duty to furnish a workplace free from recognized hazards, to assess the job for hazards, and to provide and require appropriate PPE (often at no cost to the employee). Workers must follow safety rules and use provided equipment, but the core obligation to create a safe workplace rests with the employer.

OSHA construction standards are found in which part of Title 29 of the Code of Federal Regulations?

• a.29 CFR Part 1910
• b.29 CFR Part 1904
• c.29 CFR Part 1926✓
• d.29 CFR Part 40

OSHA's safety and health standards for the construction industry are contained in 29 CFR Part 1926. (General industry standards are in Part 1910, and injury recordkeeping requirements are in Part 1904.) Knowing that construction work is governed by Part 1926 helps you locate specific rules — for example, fall protection at 1926.501 and excavations at 1926.651-652.

OSHA requires that a 'competent person' inspect excavations. What defines a competent person under 29 CFR 1926?

• a.One who can identify hazards and can correct them promptly✓
• b.The crew member with the most years on the job
• c.A worker who has completed OSHA safety training
• d.Any supervisor the employer puts in charge

OSHA defines a competent person as one who is capable of identifying existing and predictable hazards in the surroundings or working conditions and who has the authorization to take prompt corrective measures to eliminate them. For excavations (29 CFR 1926.651), a competent person must inspect the trench and protective systems daily and as conditions change. The role requires both knowledge and the authority to act.

Under OSHA's Hazard Communication Standard, what document must be available to workers to inform them about the hazards of a chemical product on site?

• a.A building permit
• b.A certificate of occupancy
• c.A mechanic's lien
• d.A Safety Data Sheet (SDS)✓

The Hazard Communication Standard (29 CFR 1926.59, adopting 1910.1200) requires that hazardous chemicals be labeled and that a Safety Data Sheet (SDS) be readily accessible to workers. The SDS describes the chemical's hazards, safe handling, protective measures, and first-aid and emergency response information. Workers have a 'right to know' the dangers of the materials they handle, and the SDS is the core document delivering that information.

OSHA identifies the 'Fatal Four' hazards responsible for the majority of construction worker deaths. Which of the following is one of them?

• a.Paperwork errors
• b.Falls to a lower level✓
• c.Parking violations
• d.Late material deliveries

OSHA's 'Fatal Four' (sometimes called the Focus Four) are the leading causes of construction fatalities: falls, struck-by incidents, electrocutions, and caught-in/between hazards. Falls are consistently the single largest category, which is why fall protection (29 CFR 1926.501) is so heavily emphasized and enforced. Focusing safety efforts on these four hazard types prevents the greatest share of deaths.

Before workers enter a permit-required confined space (such as a manhole or tank), a critical first step under OSHA is to:

• a.Test the atmosphere before and during entry✓
• b.Send in one worker briefly to check the air
• c.Ventilate the space and enter without testing
• d.Open the cover and let the space air out for an hour

Permit-required confined spaces can contain oxygen-deficient or toxic/flammable atmospheres that are not obvious. OSHA requires that the atmosphere be tested and monitored — for oxygen content, flammable gases, and toxic substances — before and during entry, along with a permit system, attendant, and rescue plan. Many confined-space deaths occur when would-be rescuers rush in; atmospheric testing and proper procedures prevent these tragedies.

The safety procedure of 'lockout/tagout' is primarily used to:

• a.Lock the job-site tool trailer at night
• b.Tag completed work as ready for inspection
• c.Control hazardous energy during servicing✓
• d.Restrict tool use to trained operators only

Lockout/tagout (LOTO) is the practice of isolating and de-energizing equipment and applying locks and tags so that machinery or electrical systems cannot be accidentally energized or started while a worker is servicing or repairing them. It protects against the sudden release of hazardous energy — electrical, mechanical, hydraulic — that could injure or kill the person working on the equipment. It is a key control against electrocution and caught-in hazards.

A personal fall-arrest system used on a construction site generally consists of which three basic components?

• a.A hard hat, safety glasses, and gloves
• b.A guardrail, a safety net, and a toeboard
• c.A body belt, a rope grab, and a warning line
• d.An anchorage, a full-body harness, and a connector✓

A personal fall-arrest system (PFAS) has three essential parts, sometimes remembered as the ABCs: an Anchorage point strong enough to hold the forces of a fall, a full-Body harness worn by the worker, and a Connector such as a shock-absorbing lanyard or self-retracting lifeline linking the harness to the anchor. All three must be present and properly rated; a harness alone provides no protection without a proper anchor and connector.

Under OSHA's steel erection standard, an ironworker on a walking/working surface with an unprotected edge must generally be protected from falling above what height?

• a.More than 10 feet above a lower level, the same trigger used for scaffold platforms
• b.More than 6 feet above a lower level, the same trigger used for most construction work
• c.More than 15 feet above a lower level, the trigger written for steel erection work✓
• d.More than 30 feet above a lower level, once two full floors have been decked

Subpart R (29 CFR 1926.760) sets the steel erection trigger at more than 15 feet, higher than the 6-foot rule Subpart M applies to most construction. Connectors working over 15 and up to 30 feet must be provided with fall arrest, positioning, or restraint equipment and be able to tie off, and must be protected from falls of more than two stories or 30 feet, whichever is less. The 10-foot figure belongs to scaffolds under Subpart L.

A mason works on a supported scaffold platform. Under OSHA's scaffold standard, fall protection is required once that platform is more than how high above a lower level?

• a.More than 10 feet, under the scaffold rules of Subpart L✓
• b.More than 6 feet, under the general construction rule of Subpart M
• c.More than 4 feet, under the general-industry walking-surface rule
• d.More than 20 feet, once the scaffold has been tied to the building

Scaffolds are governed by Subpart L, and 29 CFR 1926.451(g)(1) requires fall protection for each employee on a scaffold more than 10 feet above a lower level. The 6-foot figure is the Subpart M trigger for most other construction surfaces, and 4 feet is a general-industry threshold that does not govern construction work. Guardrails are the usual means on a supported scaffold; the height at which the scaffold must be tied off is a separate stability requirement.

A guardrail system is the fall protection along an open-sided floor. Besides sitting about 42 inches above the walking surface, what must the top rail do?

• a.Be marked with warning tape instead of being tested for any particular load
• b.Support a worker suspended from it in a personal fall-arrest system
• c.Withstand at least 50 pounds of force applied outward or downward
• d.Withstand at least 200 pounds of force applied outward or downward✓

29 CFR 1926.502(b) puts the top edge of a guardrail at 42 inches plus or minus 3 inches and requires it to withstand at least 200 pounds applied within 2 inches of the top edge in any outward or downward direction. Midrails must hold 150 pounds and toeboards 50 pounds. A guardrail is a passive barrier that keeps a worker from reaching the edge; it is not rated as a fall-arrest anchorage, and marking tape is not a substitute for a rail that meets the strength test.

An anchorage used to attach a worker's personal fall-arrest system must meet which requirement?

• a.Support at least 5,000 pounds per employee attached, or be designed by a qualified person to a safety factor of two✓
• b.Support at least 500 pounds per attached employee, which is roughly the weight of two workers and the tools they carry
• c.Be the nearest available pipe, conduit, or duct hanger, since any overhead steel will easily hold a falling worker
• d.Support the worker's body weight alone, because the shock-absorbing lanyard takes care of all the remaining load

29 CFR 1926.502(d)(15) requires anchorages for fall-arrest equipment to be independent of any anchorage supporting a platform and capable of supporting at least 5,000 pounds per employee attached, unless they are designed, installed, and used under the supervision of a qualified person as part of a system maintaining a safety factor of at least two. Arresting a fall generates forces far beyond body weight, which a shock absorber reduces but does not eliminate. Small pipe and duct hangers are not rated anchorages.

When a personal fall-arrest system stops a fall on a construction site, OSHA requires that the system:

• a.Allow a free fall of up to 12 feet, provided the worker wears a body belt rather than a harness
• b.Limit free fall to no more than 6 feet, and never allow the worker to contact a lower level✓
• c.Bring the worker to a stop within 10 feet, measured from the anchor to the harness D-ring
• d.Allow any free-fall distance at all, so long as the lanyard has a shock-absorbing pack sewn in

29 CFR 1926.502(d)(16) requires the system to be rigged so the employee can neither free fall more than 6 feet nor contact any lower level, to limit maximum arresting force to 1,800 pounds when used with a body harness, and to limit deceleration distance to 3.5 feet. Body belts have not been acceptable in a fall-arrest system since January 1, 1998. A shock absorber lowers arresting force but does not license an unlimited fall, and there is no 10-foot stopping rule.

A worker's personal fall-arrest system stops his fall and leaves him hanging 20 feet above the ground. What does OSHA require of his employer?

• a.Nothing more on site, because the fall-arrest system has already done its job
• b.Only that the incident be written into the site's daily log before the shift ends
• c.Prompt rescue of the worker, or assurance that he is able to rescue himself✓
• d.That the crew wait for the local fire department in every suspension case

29 CFR 1926.502(d)(20) requires the employer to provide for prompt rescue in the event of a fall or to assure that employees can rescue themselves. A worker left hanging in a harness can develop suspension trauma within minutes, so the rescue method has to be arranged before the work starts rather than improvised afterward. Outside responders may be one part of a plan but cannot be the whole plan where response times are long, and documenting the fall does not discharge the duty.

A skylight and several floor holes are left open on a roof deck. If covers are used instead of guardrails, OSHA requires that each cover be:

• a.Painted white so it stands out clearly, and inspected weekly by a competent person
• b.Able to hold twice the weight of anyone or anything on it, secured, and marked✓
• c.Able to hold the weight of one worker, and left loose so it lifts off quickly
• d.Made of plywood at least one inch thick, and replaced at the end of each shift

Under 29 CFR 1926.502(i) a cover must support at least twice the weight of the employees, equipment, and materials that could be imposed on it, must be secured against accidental displacement by wind, equipment, or workers, and must be color coded or marked 'HOLE' or 'COVER.' Covers in roadways must hold twice the maximum axle load of the largest expected vehicle. Skylights count as holes, and the standard specifies performance, not a particular material thickness or paint color.

A contractor chooses safety nets as the fall protection for work on a bridge deck. How close to the work must the net be installed?

• a.At least 30 feet below, so a falling worker has room to decelerate safely
• b.At ground level, since the net only has to catch the worker before impact
• c.Halfway between the working surface and the ground, wherever that point happens to fall
• d.As close as practicable below the work, and in no case more than 30 feet below✓

29 CFR 1926.502(c) requires safety nets to be installed as close as practicable under the walking/working surface but in no case more than 30 feet below it, with the potential fall area unobstructed on bridges. The farther the drop, the more energy the net must absorb and the more likely the worker strikes something on the way down. Nets must be drop-tested after installation and relocation, inspected at least weekly, and defective nets removed from service.

Who must inspect an open excavation and its protective systems, and how often?

• a.A competent person, daily before work starts, as needed through the shift, and after every rainstorm✓
• b.A registered professional engineer, once before the first crew enters and again at backfill
• c.The equipment operator, at the start of each week and whenever the trench box is moved
• d.An OSHA compliance officer, on any day that workers will be inside the excavation

29 CFR 1926.651(k) requires a competent person to inspect the excavation, the adjacent areas, and the protective systems daily prior to the start of work and as needed throughout the shift, and also after every rainstorm or other hazard-increasing occurrence. Rain, vibration, and thawing change how soil behaves within hours, so yesterday's inspection says nothing about today's trench. An engineer's role is designing protective systems, and OSHA inspectors never perform the employer's own inspections.

OSHA classifies excavation soil as stable rock, Type A, Type B, or Type C. Which classification is the LEAST stable and demands the flattest slope?

• a.Stable rock, because a blasted rock face fractures unpredictably once exposed
• b.Type A, because it carries the highest unconfined compressive strength of the group
• c.Type C, which takes in granular soils, submerged soil, and soil with water seeping in✓
• d.Type B, because it sits at the midpoint and is the hardest to classify out in the field

Appendix A to Subpart P lists stable rock, Type A, Type B, and Type C in decreasing order of stability, making Type C the least stable. Type C covers granular soils such as gravel and sand, submerged soil, and soil from which water is freely seeping. For excavations 20 feet or less deep, Type C must be sloped no steeper than one and one-half horizontal to one vertical, against 1:1 for Type B and 3/4:1 for Type A. Stable rock can stand with vertical sides.

What is the practical difference between a shoring system and a trench shield (trench box)?

• a.Shoring is used only in Type A soil, while a shield is used only in Type C soil
• b.Shoring is required above 20 feet of depth, while a shield is required below it
• c.Shoring is laid out by the crew on site, while a shield must be sized by an engineer
• d.Shoring holds the trench walls up, while a shield protects workers if the walls fail✓

Shoring uses uprights, cross braces, or hydraulic members that press against the excavation faces so the walls do not move. A shield, or trench box, does not prevent a cave-in at all; it creates a protected space that resists the soil if the walls do fail, which is why workers must stay inside it. Both are protective systems under 29 CFR 1926.652 and both may be selected from manufacturer's tabulated data. A cubic yard of soil can weigh roughly 3,000 pounds, so a wall failure crushes or suffocates in seconds.

A crew is working in a trench 6 feet deep and 90 feet long. What does OSHA require for getting out of it?

• a.One ladder placed at either end of the trench, regardless of the trench's length
• b.A ladder, stairway, or ramp placed so no worker travels more than 25 feet sideways✓
• c.A rope tied to a stake at the surface, which workers may use to climb the trench wall
• d.Nothing specific, as long as a spotter stands at the surface watching the crew work

29 CFR 1926.651(c)(2) requires a stairway, ladder, ramp, or other safe means of egress in trench excavations 4 feet or more deep, positioned so no employee has more than 25 feet of lateral travel to reach it. A 90-foot trench therefore needs several access points, not one at each end. A rope is not a means of egress, and a surface spotter cannot pull a buried worker out. Seconds matter once a wall starts to slough.

Excavated soil and the equipment staged beside a trench must be kept how far from the edge?

• a.At least 2 feet back, or restrained so that nothing can fall or roll in✓
• b.At least 10 feet back, the same distance required from overhead power lines
• c.Anywhere convenient, since a spoil pile adds very little load to the wall
• d.At least half of the trench's depth back, measured from the toe of the pile

29 CFR 1926.651(j)(2) requires excavated material and equipment to be kept at least 2 feet from the edge, or held back by retaining devices, or both. A spoil pile is a real surcharge load on the trench wall as well as a source of material that can roll in on a worker's head, and it should be placed on the side away from traffic where possible. There is no half-depth rule in the standard, and 10 feet is the clearance figure for energized overhead lines.

Before an excavation is opened, what does OSHA require regarding underground utilities?

• a.That the crew dig a test pit by machine and stop only once a line has been struck
• b.That their estimated location be determined first and utility owners be contacted✓
• c.That the property owner sign a waiver accepting responsibility for any damage
• d.That gas and electric lines be located, since water and sewer pose no real hazard

29 CFR 1926.651(b) requires the estimated location of sewer, telephone, fuel, electric, water, and other underground installations to be determined before opening an excavation, and utility owners or companies to be contacted and asked to establish where their lines run. As digging approaches a marked line, its exact location must be found by safe and acceptable means such as hand digging. In practice this is the 811 one-call system. A struck water main floods a trench and destabilizes its walls.

In which situation does OSHA require the atmosphere in an excavation to be tested before workers enter?

• a.Any excavation at all, even a 2-foot footing trench dug in open farmland
• b.Only after a worker inside the excavation reports dizziness or shortness of breath
• c.Deeper than 4 feet where oxygen deficiency or a hazardous atmosphere could be expected✓
• d.Only when the excavation has been roofed over and so counts as a confined space

29 CFR 1926.651(g)(1) requires atmospheric testing before employees enter excavations greater than 4 feet deep where oxygen deficiency (less than 19.5 percent oxygen) or another hazardous atmosphere exists or could reasonably be expected, such as work in landfill areas or near stored hazardous substances. Waiting for symptoms is waiting too long, since methane and hydrogen sulfide overwhelm a worker quickly. An open trench still collects heavier-than-air gases along its floor.

Overnight rain has left several inches of standing water in an open trench. What does OSHA require before the crew resumes work inside it?

• a.Nothing further, provided the workers are issued waterproof boots and rain gear
• b.That the trench be backfilled and then re-excavated from the surface down
• c.Precautions such as water removal, special support systems, or a harness and lifeline✓
• d.That the crew work only from outside the trench for the remainder of the week

29 CFR 1926.651(h) bars employees from working in excavations with accumulated or accumulating water unless adequate precautions have been taken, including water removal monitored by a competent person, special support or shield systems, or a safety harness and lifeline. Water weakens the soil and adds weight to the wall at the same time, which is exactly why 1926.651(k) also requires a competent person's inspection after every rainstorm. Boots address comfort, not cave-in risk.

A supported scaffold and each of its components must hold its own weight plus what multiple of the maximum intended load?

• a.One and one-half times, the same factor OSHA applies to suspension ropes
• b.Two times, which matches the strength rule for covers placed over floor holes
• c.Ten times, the factor OSHA applies to all temporary construction structures
• d.Four times, and suspension ropes on suspended scaffolds must hold six times✓

29 CFR 1926.451(a)(1) requires each scaffold and scaffold component to support its own weight and at least 4 times the maximum intended load, while suspension ropes and hardware on suspended scaffolds must hold 6 times the maximum intended load. Platforms on every working level must also be fully planked or decked between the front uprights and the guardrail supports. Twice-the-load is the Subpart M rule for hole covers, not a scaffold requirement.

At what point must a supported scaffold be restrained from tipping by guying, tying, or bracing?

• a.When its height exceeds four times its base width, outrigger supports included✓
• b.When its height exceeds twice its base width, measured to the top guardrail
• c.When it reaches 20 feet in height, regardless of how wide the base has been set
• d.Only when the day's forecast calls for winds above 30 miles per hour on site

29 CFR 1926.451(c)(1) requires supported scaffolds with a height-to-base-width ratio of more than four to one, counting any outrigger supports in the base width, to be restrained from tipping by guying, tying, bracing, or equivalent means. Ties are then repeated vertically at intervals the standard specifies. A tall, narrow scaffold tips because of its own geometry rather than only in wind, and no fixed height by itself triggers the requirement.

A worker climbs the cross braces of a frame scaffold to reach the platform. Under OSHA's scaffold standard this is:

• a.Acceptable, provided the worker keeps one hand on a brace at all times
• b.Prohibited; cross braces may never be used as a means of access or egress✓
• c.Acceptable, as long as the platform sits less than 10 feet above the ground
• d.Prohibited only on suspended scaffolds, where the braces carry the load

29 CFR 1926.451(e)(1) requires a safe means of access whenever a scaffold platform is more than 2 feet above or below the point of access, and it expressly bars cross braces from serving as access. Ladders, stair towers, ramps, walkways, or integral prefabricated scaffold access must be used instead. Braces are angled, unevenly spaced, and were never designed to be climbed, so the prohibition applies regardless of platform height or scaffold type.

How often must a scaffold be inspected for visible defects, and by whom?

• a.Once a month by the scaffold's manufacturer or a licensed rental dealer
• b.Once a week by the site superintendent, who signs a tag hung at the base
• c.Once by an engineer at erection, and again only if the scaffold is moved
• d.Before each work shift by a competent person, and after any structural event✓

29 CFR 1926.451(f)(3) requires a competent person to inspect scaffolds and scaffold components for visible defects before each work shift and after any occurrence that could affect structural integrity. Separately, a scaffold may be erected, moved, dismantled, or altered only under the supervision of a competent person qualified in that work, and the scaffold itself must be designed by a qualified person. Weekly or monthly checks are far too infrequent for a structure crews reload every day.

An uninsulated power line rated under 50 kV runs beside a building. How close may a scaffold, or conductive material handled on it, come to that line?

• a.No closer than 10 feet, unless the utility de-energizes or covers the line✓
• b.No closer than 3 feet, the clearance set for insulated lines under 300 volts
• c.No closer than 20 feet, the same clearance required for cranes near power lines
• d.Any distance at all, provided the scaffold frame has been bonded to a ground rod

Table 2 in 29 CFR 1926.451(f)(6) sets 10 feet as the minimum distance from uninsulated lines under 50 kV, with additional clearance required above that voltage. The 3-foot figure applies only to insulated lines under 300 volts. A scaffold may come closer only after the utility or system operator has been notified and has de-energized, relocated, or covered the line. Grounding the frame does nothing for a worker who bridges the gap with a length of pipe.

An extension ladder with 24 feet of working length leans against a wall. Under OSHA's rule for setting a non-self-supporting ladder, how far from the wall should its feet be?

• a.About 3 feet, which is also how far the rails must reach above a landing
• b.About 12 feet, which is half the working length and the widest possible base
• c.About 6 feet, one quarter of the working length of the ladder✓
• d.About 8 feet, one third of the working length of the ladder

29 CFR 1926.1053(b)(5)(i) requires a non-self-supporting ladder to be set so the horizontal distance from the top support to the foot is approximately one quarter of the working length, the familiar 4-to-1 rule. For a 24-foot working length that is 6 feet. Set too steep, the ladder tips backward as the worker climbs; set too flat, the feet slide out. The 3-foot figure is the separate requirement that side rails extend above an upper landing.

A portable ladder is used to reach a second-floor landing. What does OSHA require at the top of that ladder?

• a.That the rails stop level with the landing so nothing snags a worker's clothing
• b.That the side rails extend at least 3 feet above the landing being served✓
• c.That the rails extend at least 6 feet above the landing to act as a guardrail
• d.That a second worker hold the ladder whenever anyone steps off at the top

29 CFR 1926.1053(b)(1) requires the side rails of a portable ladder used for access to an upper landing surface to extend at least 3 feet above that surface. Where the ladder is too short to do so, it must be secured at the top to a rigid support and a grasping device such as a grab rail provided. The extension gives the worker something to hold while stepping on and off, which is where most ladder falls begin. Holding a ladder by hand is not a substitute for securing it.

A finish carpenter stands on the very top cap of a 6-foot stepladder to reach a ceiling box. What is wrong with this?

• a.OSHA prohibits using the top or top step of a stepladder as a step✓
• b.OSHA allows it only if a coworker braces the ladder from the front
• c.Nothing, because a stepladder's top cap carries the same duty rating
• d.OSHA allows it only on ladders rated Type IA for heavy-duty industrial use

29 CFR 1926.1053(b)(13) states plainly that the top or top step of a stepladder shall not be used as a step. Standing there raises the worker's center of gravity above the ladder's support and leaves nothing to hold, and no duty rating changes that geometry. Cross-bracing on the rear section may not be climbed either, unless the ladder was designed and built with steps on both the front and rear sections. The fix is a taller ladder or different access.

A worker finds a portable ladder with a cracked side rail. What does OSHA require be done with it?

• a.Repair it with a splint of scrap lumber and return it to the rack for reuse
• b.Keep using it only for climbs shorter than the height of the damaged rail
• c.Set it by the tool trailer and mention the crack at the next toolbox talk
• d.Mark or tag it 'Do Not Use' and withdraw it from service until it is repaired✓

29 CFR 1926.1053(b)(16) requires a portable ladder with structural defects to be immediately marked as defective or tagged 'Do Not Use' and withdrawn from service until repaired, and 1926.1053(b)(18) requires any repair to restore the ladder to its original design criteria. Leaving a cracked ladder where the next crew can grab it is precisely the failure the rule prevents. A field splint does not restore design strength, and a competent person must also inspect ladders periodically and after any damaging event.

A temporary stairway is built for access during construction. At what point does OSHA require it to have a handrail and a stair rail system?

• a.Once it has eight or more risers, which is roughly one full story of rise
• b.Once it has four or more risers or rises more than 30 inches, whichever is less✓
• c.Once it rises more than 6 feet, matching the general fall protection trigger
• d.Only once the stairway becomes a permanent part of the finished building

29 CFR 1926.1052(c)(1) requires stairways having four or more risers, or rising more than 30 inches, whichever is less, to be equipped with at least one handrail and one stair rail system along each unprotected side or edge. Stair rails installed after March 15, 1991 must be at least 36 inches high, and handrails and stair rail top rails must withstand at least 200 pounds. The rule governs temporary construction stairways, not only stairs that stay in the finished building.

To protect workers using 120-volt, 15- and 20-ampere receptacle outlets that are not part of a building's permanent wiring, an employer must:

• a.Post a sign warning that the outlets are temporary and test them once a year
• b.Rely on the breaker in the panel, which trips well before a shock can occur
• c.Use ground-fault circuit interrupters or an assured equipment grounding program✓
• d.Route every cord through a step-down transformer feeding 12-volt hand tools

29 CFR 1926.404(b)(1) gives employers exactly two choices on construction sites: approved ground-fault circuit interrupters on all 120-volt, single-phase, 15- and 20-ampere receptacles that are not part of the permanent wiring, or a written assured equipment grounding conductor program covering every cord set, receptacle, and cord-and-plug tool, with scheduled inspections and testing. An ordinary breaker protects conductors from overload; it does not open at the few milliamps that stop a heart.

A crew is moving equipment beneath an overhead line whose voltage nobody on site knows. How must the crew treat that line?

• a.As de-energized, because utilities cut power to lines above active job sites
• b.As safe to touch, since the black weatherproof covering insulates the wire
• c.As energized only during business hours, when the utility carries peak load
• d.As energized until the owner says otherwise and it is visibly grounded✓

29 CFR 1926.600(a)(6) requires that any overhead wire be considered an energized line until the person owning the line or the electrical utility indicates otherwise and the line has been visibly grounded. For lines rated 50 kV or below, at least 10 feet of clearance must be kept between the line and any part of the equipment or load, with more required at higher voltages. The dark covering on a distribution conductor is weatherproofing, not insulation rated for contact.

A helper hands you an extension cord with a split jacket and a missing ground pin. What is the correct action?

• a.Remove it from service; worn or damaged cords may not be used✓
• b.Wrap the split with electrical tape and keep the cord in service today
• c.Use it only for light strings, which draw very little current per outlet
• d.Use it only with double-insulated tools, which need no grounding pin

29 CFR 1926.416(e)(1) states that worn or frayed electric cords or cables shall not be used, and the same paragraph bars fastening extension cords with staples or hanging them from nails. The equipment grounding conductor is one of the two paths that keeps a tool's metal housing at ground potential, so a missing pin defeats the protection. Tape restores appearance, not insulation value. A double-insulated tool has no ground pin, but that does not make a damaged cord safe for any use.