NCCER Industrial Maintenance Mechanic common mistakes
NCCER Industrial Maintenance Mechanic · Understand the traps and how to avoid them.
Applies a personal lock and tag to the disconnect, then starts work without performing the try-out or releasing stored hydraulic, pneumatic, or spring energy.
Lockout/tagout gets memorized as a hardware checklist (lock, tag, done) and the verification step feels redundant, especially in scenario questions where a supervisor or another craft 'already shut it down.'
What to do instead
Drill the sequence as six ordered actions: notify, shut down, isolate, lock and tag, release or block stored energy, verify by try-start. On every scenario item, ask 'which of the six is missing?' before reading the answer choices, and never accept an option that begins work before the try-out.
Answers confined-space scenarios by having a coworker or the attendant enter to drag out an unconscious entrant, or skips pre-entry air testing because the space 'looked clean' or 'was just opened.'
Normal rescue instinct overrides the role definitions, and candidates blur the duties of entrant, attendant, and rescue service because they have memorized the words but not who may do what.
What to do instead
Memorize the attendant's job as stand-by, monitor, and summon rescue; the attendant never enters. Entry requires a permit plus pre-entry testing for oxygen, flammables, and toxics, and rescue must be by trained rescue service or non-entry (tripod/retrieval) means. Reject any answer where an untrained or unprotected person goes in.
Reads a sling's rated capacity and assumes each leg carries half the load no matter what angle the legs make, using the same number for a vertical hitch and a basket or two-leg hitch at 30 degrees.
The angle multiplier is memorized as an isolated table rather than understood as vector resolution, so under time pressure the correction is simply forgotten and 'half the load per leg' sounds right.
What to do instead
Anchor the factors for a symmetric two-leg hitch: tension per leg is about 1.00x the load at 30 degrees from horizontal, 0.71x at 45 degrees, and 0.58x at 60 degrees, always more than half the load. Keep the included angle between legs at or under 120 degrees and check the tag for the hitch type actually being used.
Takes a dimension by scaling directly off the drawing, or assumes the top view sits above the front view without checking the projection symbol in the title block.
A print is read as a picture of the part rather than as a projection convention plus a title block, revision block, and general notes that carry the controlling information.
What to do instead
Before answering, identify the projection symbol: third-angle puts the top view above the front view and the right-side view to its right; first-angle reverses this. Then take dimensions from the dimension lines and notes (never scale, especially on a print marked DO NOT SCALE) and confirm you are working to the latest revision.
Tightens a flange by going around the bolt circle in order, bringing each bolt to full torque in a single pass, and calls the joint complete.
The cross pattern exists to seat the gasket evenly, but a circular sequence feels systematic and is faster; exam wording like 'tighten the flange bolts' gives no hint that sequence and staging are the point.
What to do instead
Snug the flange parallel, then torque in a star/cross pattern in at least three stages (roughly 30, 60, and 100 percent of final torque), alternating to opposite bolts. Use the specified lubricant and torque values, and re-torque after thermal cycling where the procedure calls for it.
Checks coupling alignment with a straightedge and feeler gauge, stops when the gap 'looks even,' and bolts the machine down without checking soft foot or pipe strain.
Rough alignment is confused with precision alignment, and soft foot is invisible at the coupling, so it is filed away as a separate subject instead of the first step of alignment.
What to do instead
Work in order: correct soft foot first (one anchor bolt loose at a time, shim to a few thousandths), then correct angular (face/parallel) misalignment before offset, confirm with the specified method (dial indicator or laser), re-check after tightening anchors and after piping is connected, and apply thermal growth offsets where required.
Tops off a bearing housing with whatever grease gun is closest, and keeps pumping until grease pushes out of the relief, mixing thickener bases.
Grease is treated as generic lubricant rather than a formulation with a specific thickener base, and 'more is safer' feels intuitive when the goal is preventing failure.
What to do instead
Identify the thickener from the label or PM sheet before adding, never mix incompatible bases (for example lithium complex into polyurea), purge the fitting and gun when switching products, and apply the specified quantity. Over-greasing a high-speed bearing causes churning, heat, and seal damage.
Diagnoses a slow, weak cylinder by turning up the relief valve setting, then replaces the pump when pressure still does not build.
Pressure and flow controls are conflated; the relief valve is treated as a power adjustment rather than a safety limit, and internal leakage past the piston seal or a clogged inlet strainer is not considered.
What to do instead
Separate the circuit into pressure versus flow. Check inlet strainers and fluid level, verify pump flow with a flow meter or load valve, confirm the relief setting against spec with a gauge, then isolate the cylinder to test for bypass past the piston seal. Never set relief above a component rating to chase a symptom.
Troubleshoots a motor starter by swapping parts (coil, overloads, then the motor) without taking voltage readings across each contact and each phase to locate the open or the grounded leg.
Part-swapping feels like faster action than meter work, and candidates are not fluent in the rule that a closed contact shows near-zero volts across it while an open contact shows full voltage.
What to do instead
Meter the circuit methodically: verify line voltage L1-L2-L3 at the disconnect, then measure across each set of contacts, the overload heaters, and the control circuit. Near-zero volts across a device means it is closed; full voltage means it is open. Check voltage at the coil and winding resistance/imbalance to ground before condemning the motor.
Treats a single vibration or infrared reading as a verdict, and signs off a PM route without recording the as-found readings, units, or measurement location.
Predictive tools are treated as pass/fail gauges instead of trend data, and documentation feels like paperwork rather than part of the inspection itself.
What to do instead
Compare each reading to its own baseline and trend plus published severity bands before acting. Match the signature to the fault: 1x running speed points to imbalance, 2x to misalignment, bearing defect frequencies with high-frequency energy to a rolling-element defect. Record the as-found numbers, units, load, and exact measurement point so the next route can trend them.