OSHA 30 Construction common mistakes
OSHA 30 Construction · Understand the traps and how to avoid them.
Reaching for the General Duty Clause as the answer any time a scenario describes an unsafe condition, instead of identifying the specific standard that applies.
Candidates learn the General Duty Clause early in the Introduction to OSHA domain and over-apply it, because it sounds like a catch-all; they also under-remember which parts of 29 CFR 1926 cover which hazard.
What to do instead
Drill the rule: the General Duty Clause (Section 5(a)(1)) is used only when no specific OSHA standard applies to the hazard. Before selecting it, ask whether a 1926 subpart addresses the hazard (e.g., Subpart M for falls, Subpart P for excavations). If yes, the citation is the specific standard, not 5(a)(1).
Using the 6-foot general fall protection trigger for every elevated-work question, including scaffolds and ladders.
The 6-foot threshold in 1926.501 is the most repeated number in the course, so it becomes the default answer even where a different trigger or rule governs.
What to do instead
Memorize the threshold table as a set of distinct numbers: 6 ft for general construction surfaces/unprotected edges; 10 ft for scaffolds (fall protection required, and guardrails required on all open sides); ladders require a 3-ft extension above the landing and the 4:1 angle. Match the number to the structure named in the question before answering.
Accepting a scenario where workers pass beneath a suspended load because hard hats are worn or a signal person is present.
Candidates conflate PPE with hazard elimination and think head protection converts an unsafe practice into a compliant one, so they pick the 'yes, it is permitted' option.
What to do instead
Anchor on the absolute rule: employees are never permitted to work or pass under a suspended load, regardless of PPE. Hard hats reduce injury severity; they do not make an exclusion zone safe. If an answer choice allows work under a load, eliminate it first.
Misclassifying incident scenarios in the Focus Four taxonomy, for example labelling a trench wall collapse as 'struck-by' or a falling tool hitting a worker as 'caught-in/between'.
The categories overlap in casual language, and candidates answer from the injury description rather than from the mechanism that caused it.
What to do instead
Classify by mechanism before reading the answer choices: struck-by = a worker is hit by or strikes against an object in motion; caught-in/between = a body part is pinched, crushed, or buried by equipment, material, or collapsing earth. A cave-in buries the worker, so it is caught-in/between; a tool falling onto a worker is struck-by.
Applying a single fixed power-line clearance distance (usually 10 feet) to every crane or equipment scenario, regardless of the voltage given.
The minimum 10-foot distance is the most memorable figure, and candidates skim past the voltage value embedded in the question stem.
What to do instead
Learn the clearance as a voltage-based table rather than one number: 10 ft for lines up to 50 kV, 15 ft for over 50 kV up to 200 kV, 20 ft for over 200 kV up to 350 kV, and increasing from there. Always locate the voltage in the stem and answer from that row; if no voltage is stated, choose the option that calls for de-energizing or confirming with the utility.
Assuming the employee must supply and pay for required PPE, or assuming the employer pays for everything including ordinary work clothing and non-specialty safety-toe footwear.
Real-world experience with boots and prescription glasses conflicts with the standard, so candidates answer from personal practice instead of the requirement.
What to do instead
Fix the default in mind: the employer must provide required PPE at no cost to the employee. Then memorize the narrow exceptions the employer is not required to pay for: non-specialty safety-toe footwear and non-specialty prescription safety eyewear that the employee may wear off the job, and everyday clothing. Also remember PPE selection follows a written hazard assessment and employees must be trained on it.
Choosing a respirator as the correct control for a dust, fume, or vapor exposure scenario when engineering or administrative controls are also offered.
PPE is the most visible and familiar control, and candidates substitute it for the hierarchy of controls rather than ranking it last.
What to do instead
Apply the hierarchy explicitly in order: elimination, substitution, engineering controls (wet cutting, local exhaust ventilation, enclosed cabs), administrative/work-practice controls, then PPE as the last line of defense. When a question asks for the 'best' or 'most effective' control, pick the highest option on that list; choose the respirator only when the question asks what PPE is required after other controls are in place.
Missing the 3-foot extension above the landing and the 4:1 setup angle on portable ladder questions, or accepting a fully extended ladder that is tied off but still short of the landing.
Candidates remember 'tie it off' as the complete ladder rule and forget that the access requirement is separate from the securing requirement.
What to do instead
Use the two-number checklist every time a portable ladder appears: side rails extend at least 3 feet above the upper landing surface (or a grab device is provided if that is not possible), and the base is set at 1 foot out for every 4 feet of working length (about 75 degrees). Tying off, securing the base, and maintaining three points of contact are additional requirements, not substitutes.
Answering excavation scenarios without applying the 5-foot protective-system trigger, the 2-foot spoil-pile setback, and the daily competent-person inspection.
Candidates treat trenching as a single fact ('shoring') rather than a bundle of numeric requirements, and they skip the inspection step because it is not a physical object in the scene.
What to do instead
Run the excavation checklist in order: protective system required at 5 feet or deeper (and shallower if the competent person identifies a hazard); spoil, equipment, and materials kept at least 2 feet back from the edge; competent person inspects daily and after rain or other hazard-increasing events; ladder or ramp within 25 feet of lateral travel for egress; atmospheric testing where a hazardous atmosphere could exist.
Approving a lift because the rigging 'looks fine' and the load is below the crane's maximum rating, without addressing the load chart configuration, the swing radius, or the required inspection interval.
Candidates remember 'stay under capacity' as the whole rule and overlook that capacity depends on boom length, radius, and configuration, and that access control around the rotating superstructure is a separate requirement.
What to do instead
Check three things before accepting any lifting answer: capacity must be read from the load chart for the actual radius and boom configuration, not the crane's maximum rating; the swing radius of the rotating superstructure must be barricaded or the area kept clear; and rigging must be inspected before each use by a qualified person, with periodic crane inspections on the required schedule.