Class F cheat sheet

Class F licenses authorize specific work scopes; performing work outside the licensed scope is a violation regardless of operator intent or supervision.

License renewal depends on a fixed term plus continuing-education hours; lapsed renewal usually requires reinstatement fees and may require re-examination.

Operating without a valid license is a strict-liability offense: the operator's belief that a license was current is not a defense.

Licensee must notify the authority in writing of address changes, name changes, or change of employer within the stated reporting window.

Recordkeeping rule: maintain licensing documents, test records, and work logs for the retention period specified in the regulation, and make them available on request.

Disciplinary actions escalate in a typical order: warning, fine, suspension, revocation; repeat violations within a set period trigger the higher tier.

A licensed individual is responsible for work performed under that license even when helpers or unlicensed assistants carry out the physical task.

Regulations are updated on a cycle; the edition in force at the time of the work governs, not the edition in effect when the license was issued.

Before any work: identify hazards, isolate energy sources, apply locks and tags, and verify zero energy state by test, not by assumption.

Lockout/tagout requires each worker to apply a personal lock; a tag alone is a warning device and never a substitute for a lock.

Personal protective equipment is the last line of defense: eliminate, substitute, engineer, and administrate controls first, then PPE.

Confined-space entry requires pre-entry atmospheric testing for oxygen, flammables, and toxics, plus a stand-by attendant and rescue plan.

Electrical safety rule: treat all conductors as energized until tested and grounded; use meters rated for the available fault current and voltage class.

Fire triangle: fuel, oxygen, ignition. Removing any one leg stops combustion; extinguisher class must match the fuel (A, B, C, D, K).

Fall protection is required at the trigger height set by the applicable rule; harness anchor points must meet the rated strength and be above the worker.

Incident reporting: report injuries and near misses within the required window; preserve the scene and equipment until released by the investigating authority.

Overcurrent protection devices are selected by two independent criteria: continuous current rating and interrupting (breaking) capacity versus available fault current.

Wire ampacity depends on conductor material, insulation temperature rating, ambient temperature, and the number of current-carrying conductors bundled together.

A grounded conductor (neutral) carries normal return current; a grounding conductor carries fault current only and must never carry normal current.

Voltage drop approximation: VD = 2 × K × I × L ÷ CM for single-phase two-wire circuits, where K is the resistivity constant, I the load current, L the one-way length, and CM the circular-mil area.

Transformers: primary-to-secondary current ratio is the inverse of the turns ratio; a step-down voltage means a step-up current.

Circuit breakers protect against overload and short circuit; a ground-fault device detects current imbalance and trips at a much lower threshold than an overload device.

Component ratings are ambient-dependent: a device rated for a given current at a reference temperature must be derated at higher ambient.

Terminals and connectors must be listed for the conductor material; dissimilar metals require connectors rated for the combination to avoid galvanic corrosion.

Install per the manufacturer's listing and labeling; the listing conditions override generic field practice when the two conflict.

Conductor bending radius must not be less than the minimum multiple of the cable diameter specified for the cable type and voltage class.

Support and spacing rules are set by raceway or cable type and by whether the run is horizontal, vertical, or in a hazardous location.

Torque terminations to the manufacturer's specified value with a calibrated tool; loose terminations are a leading cause of overheating and failure.

Maintenance schedule is condition-based: thermal scans, insulation-resistance trending, and torque checks at defined intervals rather than only after failure.

Any modification to a listed assembly may void the listing unless the modification is evaluated and approved by a recognized testing body.

Documentation rule: as-built drawings, panel schedules, and equipment nameplates must be updated whenever a circuit or component is changed.

Clearances for working space around equipment are measured from the equipment face and must remain unobstructed; storage in the working space is prohibited.

Insulation resistance testing applies a DC voltage and reads resistance; readings are compared to prior baseline trends, not to a single pass/fail number alone.

Continuity testing must be done on a de-energized circuit, and the meter should be zeroed or nulled against lead resistance first.

Voltage-drop diagnosis: measure at the source and at the load under load; a large difference localizes the fault to the conductors or terminations between them.

Divide-and-conquer troubleshooting isolates a fault by testing at the midpoint of a circuit, then halving the suspect segment until the fault is located.

A reading of zero volts on a live circuit indicates either a dead source or an open ahead of the test point; verify with a known-live source first.

Thermal imaging finds high-resistance joints under load; the circuit must be energized and carrying current for the scan to reveal the defect.

Ground-fault trip testing confirms the device operates within its rated trip time and current; a device that fails to trip must be removed from service.

Inspection records must capture date, tester identity, instrument calibration status, test conditions, and results so the data can be compared over time.