NCCER Rigger cheat sheet

Standard hand signals: hoist, lower, stop, emergency stop, boom up/down, swing, and travel are given by one designated signalperson only.

Load-handling rule: no person may ride the load, the hook, or the sling, and no body part may be under a suspended load.

Critical lift criteria commonly include loads over 75% of the crane's rated capacity, multiple-crane lifts, and lifts over occupied areas or hazardous equipment.

Crane capacity decreases as radius (boom-to-load horizontal distance) increases; always verify capacity at the actual working radius.

Tag lines control rotation; they are not rated rigging and must never be used to restrain a load's full weight.

Rated capacity of a sling assembly is limited by its weakest component, including shackles, hooks, and master links.

Outriggers must be fully extended with floats/pads on stable ground; capacity charts for on-rubber operation are much lower than on-outrigger charts.

A crane must be level within the manufacturer's tolerance (commonly 1%) before lifting; unlevel condition causes side loading and capacity loss.

Wire rope sling efficiency drops with D/d ratio; smaller sheave or pin diameter relative to rope diameter reduces strength (roughly 50% at D/d of 5 or less for many constructions).

Sling angle affects capacity: vertical = 100%, 60° from horizontal = 87%, 45° = 71%, 30° = 50% of vertical rated capacity.

Chain sling grades: Grade 80 and Grade 100 are standard; never repair or heat chain slings, and remove links with cracks, gouges, or stretch.

Shackle pins must be fully seated with no more than 10% thread exposure; screw-pin shackles should not be side-loaded.

Web sling color coding (industry convention): purple = 1 ton, green = 2 ton, yellow = 3 ton, red = 5 ton, blue = 8 ton, orange = 10 ton (single-leg vertical).

Synthetic web slings must be removed from service for cuts, burns, ultraviolet degradation, or missing/illegible tags.

Hooks must have a functioning latch or mousing; hook load should bear on the saddle, not the tip, and never on the latch.

Eyebolts: shoulder-type eyebolts are rated for angular loading; plain (non-shoulder) eyebolts are for vertical lift only.

Master links and master rings are marked with working load limit; never exceed the marked WLL and match hardware to sling size.

Load weight = volume × material density; steel ≈ 490 lb/ft³, concrete ≈ 150 lb/ft³, water ≈ 62.4 lb/ft³, aluminum ≈ 170 lb/ft³.

Sling tension formula: T = (W / number of legs) × (L / H), where L is sling length and H is vertical height between hook and load attachment.

For two-leg bridle: tension per leg = (W/2) ÷ sin(angle from horizontal); as angle decreases, tension increases.

Center of gravity must be directly below the hook; an off-center CG causes load tilt and unequal leg loading.

For unequal leg lengths or off-center CG, load share is inversely proportional to horizontal distance from the CG to each attachment point.

Include the weight of rigging (slings, shackles, spreader beam) in total load; rigging weight is often 5–10% of a light load.

Spreader beams convert sling angle to near-vertical at the load, reducing horizontal compression on the load and sling tension.

When lifting with more than two legs, only two are assumed to share the load unless the load is rigid and the geometry is proven equal.

Vertical hitch: full sling capacity; choker hitch: approximately 75–80% of vertical capacity; basket hitch: up to 200% when legs are vertical.

Choker hitch efficiency decreases with a small choke angle; never choke on a sharp edge without protection or a softener.

Basket hitch capacity depends on the D/d ratio and the angle of the legs; a 90° basket doubles capacity, a shallow basket does not.

Common knots for rigging: bowline (fixed loop that will not slip), clove hitch (temporary attachment), and two half hitches (securing a line).

A bowline weakens rope by roughly 25–40%; knots reduce rope strength, so never rely on a knot as a rated connection.

Lift plan elements: load weight and CG, rigging arrangement, capacity at radius, ground conditions, travel path, and communication/signalperson.

Pre-lift inspection: check slings, shackles, hooks, and crane for damage or missing tags; reject any rigging without a legible identification tag.

For a two-leg bridle at 60° from horizontal, each leg carries about 58% of the load; at 30°, each leg carries 100% of the load.

Trial lift: raise the load a few inches, verify balance, rigging, and brake holding before continuing the lift.

Lift plan must identify the load weight, the CG location, the rigging configuration, and the crane capacity at the planned radius.

Sling angle from horizontal below 30° is generally prohibited or requires engineering approval because tension rises sharply.

For a four-leg bridle with a flexible load, assume only two legs share the load unless the load is rigid and geometry guarantees equal loading.

Choker, basket, and vertical hitches each have distinct capacity factors; never apply vertical capacity to a choker hitch.

Rigging inspection intervals and records must be documented; damaged slings are tagged out of service immediately.

A spreader beam or lifting beam reduces horizontal compression and sling tension compared with a direct bridle hitch.

Signalperson and operator must agree on hand signals or radio channel before the lift; emergency stop is a single, distinct signal for anyone.

Wind, ground bearing pressure, and power-line clearance are part of the lift plan; minimum approach distance to power lines is typically 10 ft for lines up to 50 kV.

Load weight estimation: multiply volume by density; for a rectangular solid, volume = length × width × height.

Center of gravity of a symmetric object is at its geometric center; of an L-shape, it lies toward the heavier leg.

Sling tension is lowest when slings are vertical and increases as the angle from horizontal decreases.

Two-leg bridle tension per leg = W / (2 × sin θ), where θ is the angle from horizontal.

Choker hitch capacity is roughly 75–80% of the sling's vertical rated capacity because of the bend and compression at the choke.

Basket hitch with vertical legs can develop up to twice the single-leg vertical capacity because the load is shared by two parts of the sling.

Rigging hardware working load limit (WLL) must equal or exceed the calculated tension in that component.

Knots reduce rope strength; a bowline retains roughly 60–75% of the rope's rated strength.

Lift plan approval: critical lifts require a written plan reviewed by a qualified person before execution.

Pre-use inspection of slings and hardware is required each shift; damaged gear is removed from service and tagged.

Load control: tag lines keep the load from rotating; they are not rated for load weight.

Crane capacity at radius must be verified from the manufacturer's load chart for the actual boom length and configuration.

Ground bearing pressure under outriggers must be checked; soft or sloped ground requires mats or cribbing.

Power line safety: maintain the required minimum approach distance; use a spotter when working near energized lines.

Communication: one designated signalperson; anyone may give an emergency stop signal.

Load test: lift a few inches, verify balance and rigging, then proceed only after confirming stability.

Sling angle factor: tension multiplier = 1 / sin(angle from horizontal); at 30° multiplier is 2.0, at 45° it is 1.41, at 60° it is 1.15.

Number of legs sharing load: two-leg bridle assumes two legs share; four-leg assumes two unless rigid and proven equal.

Choker hitch: 75–80% of vertical capacity; basket hitch with vertical legs: up to 200% of vertical capacity.

Load weight = volume × density; steel 490 lb/ft³, concrete 150 lb/ft³, water 62.4 lb/ft³.

CG must be directly below the hook; offset CG causes tilt and unequal leg loading.

Knots (bowline, clove hitch) reduce rope strength by 25–40%; never use a knot as a rated connection.

Inspect slings and hardware each shift; remove damaged gear from service and tag it.

Critical lift: load over 75% of capacity, multiple cranes, or over occupied areas requires a written plan.

Sling tension per leg for a two-leg bridle = (W / 2) / sin θ, where θ is the angle from horizontal.

Vertical hitch uses full sling capacity; choker uses about 75–80%; basket with vertical legs uses up to 200%.

Load weight: volume × density; common densities: steel 490, concrete 150, water 62.4, aluminum 170 lb/ft³.

Center of gravity must be directly below the hook; off-center CG causes tilt and unequal loading.

Knots reduce rope strength; bowline retains roughly 60–75% of rated strength.

Critical lift plan: load over 75% of capacity, multiple cranes, or over occupied areas.

Power line minimum approach distance is typically 10 ft for lines up to 50 kV.

Pre-lift: inspect rigging, verify capacity at radius, confirm signalperson, and trial lift a few inches.

Sling angle factor = 1 / sin(angle from horizontal); at 30° it is 2.0, at 45° it is 1.41, at 60° it is 1.15.

Two-leg bridle tension per leg = W / (2 × sin θ).

Choker hitch: 75–80% of vertical capacity; basket hitch with vertical legs: up to 200%.

Load weight = volume × density; steel 490 lb/ft³, concrete 150 lb/ft³, water 62.4 lb/ft³.

CG must be directly below the hook; offset CG causes tilt and unequal leg loading.

Knots reduce rope strength by 25–40%; never use a knot as a rated connection.

Inspect slings and hardware each shift; remove damaged gear from service and tag it.

Critical lift: load over 75% of capacity, multiple cranes, or over occupied areas requires a written plan.

Sling tension per leg for a two-leg bridle = (W / 2) / sin θ, where θ is the angle from horizontal.

Vertical hitch uses full sling capacity; choker uses about 75–80%; basket with vertical legs uses up to 200%.

Load weight: volume × density; common densities: steel 490, concrete 150, water 62.4, aluminum 170 lb/ft³.

Center of gravity must be directly below the hook; off-center CG causes tilt and unequal loading.

Knots reduce rope strength; bowline retains roughly 60–75% of rated strength.

Critical lift plan: load over 75% of capacity, multiple cranes, or over occupied areas.

Power line minimum approach distance is typically 10 ft for lines up to 50 kV.

Pre-lift: inspect rigging, verify capacity at radius, confirm signalperson, and trial lift a few inches.

Sling angle factor = 1 / sin(angle from horizontal); at 30° it is 2.0, at 45° it is 1.41, at 60° it is 1.15.

Two-leg bridle tension per leg = W / (2 × sin θ).

Choker hitch: 75–80% of vertical capacity; basket hitch with vertical legs: up to 200%.

Load weight = volume × density; steel 490 lb/ft³, concrete 150 lb/ft³, water 62.4 lb/ft³.

CG must be directly below the hook; offset CG causes tilt and unequal leg loading.

Knots reduce rope strength by 25–40%; never use a knot as a rated connection.

Inspect slings and hardware each shift; remove damaged gear from service and tag it.

Critical lift: load over 75% of capacity, multiple cranes, or over occupied areas requires a written plan.

Sling tension per leg for a two-leg bridle = (W / 2) / sin θ, where θ is the angle from horizontal.

Vertical hitch uses full sling capacity; choker uses about 75–80%; basket with vertical legs uses up to 200%.

Load weight: volume × density; common densities: steel 490, concrete 150, water 62.4, aluminum 170 lb/ft³.

Center of gravity must be directly below the hook; off-center CG causes tilt and unequal loading.

Knots reduce rope strength; bowline retains roughly 60–75% of rated strength.

Critical lift plan: load over 75% of capacity, multiple cranes, or over occupied areas.

Power line minimum approach distance is typically 10 ft for lines up to 50 kV.

Pre-lift: inspect rigging, verify capacity at radius, confirm signalperson, and trial lift a few inches.

Sling angle factor = 1 / sin(angle from horizontal); at 30° it is 2.0, at 45° it is 1.41, at 60° it is 1.15.

Two-leg bridle tension per leg = W / (2 × sin θ).

Choker hitch: 75–80% of vertical capacity; basket hitch with vertical legs: up to 200%.

Load weight = volume × density; steel 490 lb/ft³, concrete 150 lb/ft³, water 62.4 lb/ft³.

CG must be directly below the hook; offset CG causes tilt and unequal leg loading.

Knots reduce rope strength by 25–40%; never use a knot as a rated connection.

Inspect slings and hardware each shift; remove damaged gear from service and tag it.

Critical lift: load over 75% of capacity, multiple cranes, or over occupied areas requires a written plan.

Sling tension per leg for a two-leg bridle = (W / 2) / sin θ, where θ is the angle from horizontal.

Vertical hitch uses full sling capacity; choker uses about 75–80%; basket with vertical legs uses up to 200%.

Load weight: volume × density; common densities: steel 490, concrete 150, water 62.4, aluminum 170 lb/ft³.

Center of gravity must be directly below the hook; off-center CG causes tilt and unequal loading.

Knots reduce rope strength; bowline retains roughly 60–75% of rated strength.

Critical lift plan: load over 75% of capacity, multiple cranes, or over occupied areas.

Power line minimum approach distance is typically 10 ft for lines up to 50 kV.

Pre-lift: inspect rigging, verify capacity at radius, confirm signalperson, and trial lift a few inches.