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BLD-LINE69-02 · Lesson 2 · 7 clock hours · demo

Ground School: Body Mechanics, Gaff Placement, and Hazard Recognition

Objective. Students will describe and physically demonstrate on a ground-level practice pole section the correct body lean angle, knee-out technique, and gaff strike angle that prevent gaff-outs, and will identify at least five hazardous pole conditions from photographs and a real pole inspection.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by a licensed professional engineer or master tradesperson or by a certification or approval body. It is a study draft and may contain errors. Do not use it as instructions for work on a job site or on live equipment. Always follow your instructor, your supervising professional, and current official references and regulations.

VoTechWorks program approval and accreditation are still in progress. Credentials are issued only by the certifying bodies named in each program, after their own exams.

Why Ground School Comes First

No student climbs a real pole until they can prove their body mechanics on the ground. Gaff-outs — the sudden loss of purchase when a gaff spike pulls free of the wood — are the leading cause of falls in pole climbing. They are almost always caused by incorrect body position, wrong gaff angle, or failure to recognize a compromised pole before the climb begins. This lesson trains those three skills at zero elevation so the movements become automatic before height is added.

Body Lean: Your Most Important Habit

When you stand against a utility pole, your instinct is to hug it. That instinct will get you hurt. Correct technique requires your chest to be approximately 10–12 inches away from the pole surface at all times. You can verify this with a measuring tape during practice.

Why does lean matter? When you lean away from the pole, your body weight loads down through your legs and into the gaffs at an angle that drives the spike deeper into the wood. When you hug the pole, your weight shifts inward, the gaff angle flattens, and the spike skips out of the wood — a gaff-out.

Maintain the lean by keeping your hips back, your arms relatively extended (not locked), and your eyes looking upward in the direction of travel. Think of your body forming a slight "C" shape away from the pole.

Knees Out: The Other Half of the Equation

Your knees must stay out, away from the pole, throughout every stride. When your knees come in and contact the pole, the inner edge of the gaff shank drags on the wood and levers the spike outward — again, a gaff-out. Keeping your knees out lets the gaff drive straight in.

A useful cue: imagine you are straddling a barrel. Your knees point outward, your thighs are not touching the pole, and the inside of your boot — where the gaff is mounted — faces the wood cleanly.

Gaff Strike Angle

The gaff spike must enter the wood at the correct downward angle — not too steep and not too shallow. A strike that is too shallow skims across the surface and pops out. A strike that is too steep digs in but makes it difficult to extract the gaff cleanly for the next step, wasting energy and disrupting rhythm.

In practice, you achieve the correct angle by keeping proper body lean and allowing your leg to swing naturally from the hip. The gaff follows the geometry of your body. If your lean and knee position are right, the angle is right. This is why all three elements are trained together.

The Deliberate Gaff-Out Demonstration

During the instructor demonstration, you will watch a gaff-out performed on purpose. Pay attention to the sound — a short, sharp scrape — and the body movement that follows: a sudden downward lurch. Recognizing that sound and feel is important. If you hear or feel a partial gaff-out while climbing, your trained response is to immediately press your body away from the pole and re-seat the opposite gaff rather than grabbing the pole in panic.

Weight Transfer

Climbing is a rhythm of four events: plant the gaff, load your weight onto that leg, step the opposite foot up, plant the new gaff. Full weight transfer to each gaff as you step is essential. Hesitant, partial transfers leave both gaffs lightly loaded and increase the risk of both pulling free simultaneously.

Hazard Recognition Before Every Climb

A lineworker inspects a pole from the ground before touching it. You are looking for conditions that can cause the pole to fail structurally or that can trap or injure you during the climb. Learn to identify each of the following:

Any of these conditions requires evaluation before climbing. When in doubt, treat the pole as a no-climb and notify your supervisor.

PPE for This Lesson

Even at ground level with gaffs, you must wear leather lineworker climbing boots with gaffs properly adjusted and secured, hard hat, safety glasses, and leather work gloves. Gaffs at ankle height are still capable of causing serious puncture wounds. No exceptions.

What Success Looks Like

By the end of this lesson you will be able to plant 20 consecutive gaff strikes into a ground-level pole section with zero gaff-outs, maintain the 10–12-inch body lean confirmed by a partner or instructor, keep your knees out on every strike, and name the defect in each of ten pole photographs. These are the foundations every skill in the climbing sequence is built on.

Key terms9

Gaff-outThe uncontrolled release of a gaff spike from the pole wood, usually caused by incorrect body lean, wrong strike angle, or a compromised pole surface; the primary mechanical cause of climbing falls.
Body leanThe deliberate positioning of the climber's chest approximately 10–12 inches away from the pole surface, which loads the gaffs at the correct downward angle to maintain purchase.
GaffThe hardened steel spike attached to the inner ankle of a lineworker's climbing gaff set, driven into the pole wood to support the climber's weight at each step.
Ground-line deteriorationRot and decay concentrated at the soil line of a wood utility pole, where moisture, oxygen, and soil microorganisms combine to degrade wood fiber; the most common structural failure zone.
Shell rotDecay limited to the outer layers of a pole while the core may appear intact; the softened outer wood cannot hold a gaff and increases gaff-out risk.
Heart rotDecay of a pole's interior wood, often detected by sounding the pole with a hammer; a hollow tone indicates a void that reduces structural load capacity.
Weight transferThe deliberate, complete shift of body weight onto a newly planted gaff before lifting the opposite foot, maintaining continuous secure contact with the pole during each climbing stride.
SoundingA field inspection technique in which a worker strikes the pole with a hammer and listens for a hollow tone that indicates internal decay or voids.
Strike angleThe angle at which the gaff spike contacts the pole wood; determined by the geometry of proper body lean and knee position, and critical to achieving consistent gaff purchase.

Worked examples4

1. Your partner uses a measuring tape while you stand against the practice pole. The tape reads 7 inches from your chest to the pole surface. How far do you need to move, and in which direction?
  1. Identify the target range: correct body lean places the chest 10–12 inches from the pole surface.
  2. Subtract the current measurement from the minimum target: 10 inches − 7 inches = 3 inches.
  3. The chest is too close to the pole, so you must move your hips backward (away from the pole) to increase the distance by at least 3 inches, reaching a minimum of 10 inches.
Answer: Move hips back at least 3 inches to reach the 10-inch minimum; the acceptable range is 10–12 inches from chest to pole.
2. During the 20-strike drill, a student gaff-outs on strike 4 and again on strike 9. Does this student pass or repeat the drill, and why?
  1. Review the completion standard: students who gaff out more than twice in any 10-strike set must repeat the drill the same day.
  2. Count gaff-outs in the first 10-strike set (strikes 1–10): gaff-out on strike 4 and gaff-out on strike 9 = 2 gaff-outs in the first 10-strike set.
  3. Compare to the threshold: the rule triggers a repeat if gaff-outs exceed two (i.e., three or more) in any 10-strike set. Two gaff-outs equals the threshold but does not exceed it.
  4. Conclusion: 2 gaff-outs in a 10-strike set does not exceed the limit of 'more than twice,' so the student continues the drill but receives immediate corrective coaching on lean and angle.
Answer: The student does not yet trigger an automatic repeat (the threshold is more than two gaff-outs per 10-strike set), but the instructor provides real-time correction before the next set. If a third gaff-out occurs in any subsequent 10-strike set, the full drill is repeated that day.
3. A student measures their body lean at 13 inches. Is this within the correct range, and what adjustment, if any, is needed?
  1. Identify the correct range: 10–12 inches from chest to pole.
  2. Compare the measured value: 13 inches exceeds the 12-inch maximum by 1 inch.
  3. At 13 inches the lean is slightly too far back, which can flatten the gaff strike angle in the other direction and reduce reliable purchase.
  4. Correction: move hips slightly forward (toward the pole) by approximately 1 inch to bring the measurement back within the 10–12-inch range.
Answer: 13 inches is outside the correct range (too far). The student should move hips approximately 1 inch closer to the pole to fall within the 10–12-inch window.
4. During the hazard gallery walk, a student counts 3 no-climb poles and 7 climb poles out of 10 photographs. The instructor states that 5 of the 10 photographs should have been classified as no-climb. What is the student's classification error rate as a percentage?
  1. Determine the correct no-climb count: 5 out of 10 photographs.
  2. Determine the student's no-climb count: 3 out of 10.
  3. The student missed 5 − 3 = 2 no-climb poles (classified them as safe to climb).
  4. Each incorrectly classified photograph is one error. Total errors = 2.
  5. Error rate = (number of errors ÷ total photographs) × 100 = (2 ÷ 10) × 100 = 20%.
Answer: The student's classification error rate is 20%, meaning 2 out of 10 poles were misidentified. In the field, each missed no-climb decision is a potential fall or structural failure.
In class: Instructor demonstrates on a horizontal pole mock-up and a short (8-foot) section of pole set at ground level: body lean away from the pole (approximately 10–12 inches from chest to pole), knees out, gaff striking at the correct angle into the wood—then deliberately demonstrates a gaff-out so students can see and hear the failure mode; students watch, then narrate what they observe. · Hazard recognition gallery walk: ten numbered photographs posted around the classroom show poles with varying defects (shell rot, heart rot, woodpecker holes, foreign wire attachments, broken steps, ground-line deterioration, charring, splits, leaning poles, and evidence of insect infestation); students record the defect type and their climb/no-climb decision with a rationale for each, then debrief as a group. · Ground-level repetition drill: with gaffs donned and positioned next to an 8-foot practice pole set vertically in a tire stand, each student performs 20 alternating gaff strikes into the wood at the correct angle while maintaining proper body lean, coached by a partner reading cues from a technique card; instructor circulates and provides real-time correction.
Materials: 8-foot wood pole sections (set in tire stands or ground brackets), hazard-recognition photograph set, technique cue cards, climbing log books, NCCER Power Line Worker module reference, measuring tape (to verify 10–12-inch body lean), whiteboard for debriefing
Check: Students must complete 20 consecutive gaff strikes on the ground-level pole with zero gaff-outs and maintain correct lean as confirmed by instructor observation using a 4-point technique rubric (lean, knee position, gaff angle, weight transfer); students who gaff out more than twice in any 10-strike set repeat the drill the same day.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

NCCER Power Line Worker — Climbing Fundamentals
1. What is the primary mechanical reason for maintaining a 10–12-inch body lean away from the pole during climbing?
NCCER Power Line Worker — Climbing Fundamentals
2. During the ground-level drill, a student's knees repeatedly contact the pole surface. Which failure is most likely to result?
NCCER Power Line Worker — Pole Inspection and Hazard Recognition
3. A lineworker strikes a pole with a hammer before climbing and hears a hollow tone in the lower section. This finding most likely indicates:
NCCER Power Line Worker — Pole Inspection and Hazard Recognition
4. Which pole condition most commonly causes structural failure at the base of the pole?
NCCER Power Line Worker — Climbing Fundamentals
5. In the completion standard for the 20-strike drill, a student gaff-outs three times within a single 10-strike set. What is the correct outcome?
OSHA 10 — Personal Protective Equipment
6. Which PPE item is required during the ground-level gaff strike drill, even though the student never leaves the ground?
NCCER Power Line Worker — Pole Inspection and Hazard Recognition
7. A photograph in the hazard gallery shows a pole with charring that extends from the base upward approximately three feet. What is the most appropriate decision and reason?
NCCER Power Line Worker — Climbing Fundamentals
8. During the deliberate gaff-out demonstration, the instructor wants students to recognize the audible and physical warning signs of a gaff slipping. Which response is trained for a partial gaff-out during an actual climb?
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