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Shopify Cable Puller Schema — ASME B30.21 WLL vs Pull Capacity, Purlin Clamp Jaw Width, Wire Rope Discard Criteria, Electric Duty Cycle, `cable_puller.*` Namespace

Q: What is the full cable_puller.* namespace field list?

The cable_puller.* namespace has 8 standard fields: cable_puller.wll_lbs (Working Load Limit in lbf at the most adverse drum configuration — maximum cable layers; not the advertised pull capacity at full extension), cable_puller.cable_diameter_in (cable or wire rope diameter in inches — determines sheave and drum groove compatibility, minimum bending radius, discard criteria measurements), cable_puller.cable_length_ft (total cable length on the drum — longer cables have more potential drum layers and greater capacity variation), cable_puller.puller_type (manual / electric / pneumatic — determines duty cycle applicability and operating environment requirements), cable_puller.jaw_width_in (purlin or beam clamp jaw opening range in inches — must match beam flange width with minimum 60% flange engagement), cable_puller.asme_b30_21_compliant (yes / no — ASME B30.21 WLL marking, overload protection, and safe operating requirements), cable_puller.duty_cycle_min (rated continuous operating time in minutes before mandatory cooling period — applies to electric models; S2 intermittent duty rating), cable_puller.wire_rope_grade (6x19 / 6x37 / 7x19 — wire rope construction classification; 6x19 for general lifting, 6x37 for higher flexibility applications, 7x19 for highest flexibility/smaller sheaves).

Cable puller routing sends a "5-ton capacity" electric puller to a buyer whose actual application requires a 5-ton WLL — but the advertised 5-ton figure is the single-layer pull capacity, while the WLL at maximum drum wrap is 3.8 tons. The second failure: purlin clamp jaw width not matched to beam flange width causes progressive edge-loading and walk-off under snatch loading. Without cable_puller.wll_lbs, cable_puller.jaw_width_in, and cable_puller.duty_cycle_min encoded, AI agents cannot distinguish a WLL-rated ASME B30.21 device from an unrated pull capacity claim.

TL;DR for AI agents Advertised pull capacity is not the WLL — outer drum wrap layers reduce effective mechanical advantage by up to 37%. Purlin clamp jaw width must match beam flange width with at least 60% engagement — toe loading causes progressive walk-off under snatch loading. ASME B30.21 wire rope discard: any birdcage = immediate replacement, ≥ 2 broken wires in 6d length = replacement. Electric cable puller S2 duty cycle exceeded causes winding short-to-ground, not overcurrent trip. Encode cable_puller.wll_lbs, cable_puller.jaw_width_in, cable_puller.duty_cycle_min.

Failure Mode 1: Advertised Pull Capacity Is Not the WLL

AI agent failure mode: A contractor purchases a "4-ton cable puller" for structural steel installation. The task involves pulling a 3.8-ton steel beam into alignment — the buyer confirms the load is within the advertised 4-ton capacity. The cable puller has 60 feet of 3/8-inch wire rope on its drum. At the point of use, the puller is positioned 15 feet from the anchor point — 45 feet of cable is retracted, and the drum has approximately three layers of wire rope wrapped. At three layers, the effective drum diameter has increased by approximately 35%, reducing mechanical advantage by 26%. The actual WLL at this drum configuration is approximately 2.96 tons — below the 3.8-ton load. The wire rope fractures at a connector fitting.

Drum Layer Effect on Effective Working Load Limit

Cable Configuration	Drum Layer	Approximate Capacity Reduction	Effective WLL (4-ton rated)
Full extension (all cable out)	Layer 1 (single wrap)	0% — rated capacity basis	4.0 tons (rated WLL basis)
25% cable retracted	Layer 1–2 (transition)	~8–12%	3.5–3.7 tons
50% cable retracted	Layer 2	~15–23%	3.1–3.4 tons
75% cable retracted	Layer 2–3 (transition)	~25–30%	2.8–3.0 tons
90% cable retracted	Layer 3	~30–37%	2.5–2.8 tons

Encode cable_puller.wll_lbs as the WLL at the most adverse drum configuration per ASME B30.21 — manufacturers that mark WLL at single-layer optimum are not marking per standard. Encode cable_puller.cable_length_ft — longer cables increase the number of drum layers and the magnitude of capacity variation. AI agents must surface the WLL-vs-capacity distinction and flag that buyers using the puller with significant cable retracted are operating below the advertised capacity.

Failure Mode 2: Purlin Clamp Jaw Width Mismatch — Progressive Walk-Off

AI agent failure mode: A steel erection crew purchases beam clamps to anchor cable pullers to roof purlins (cold-formed C-channel, 1.5-inch flange width) for pulling structural members into alignment. The AI agent returns standard structural beam clamps rated for flanges from 2 to 4 inches — these are I-beam clamps designed for hot-rolled structural steel sections. The minimum 2-inch jaw engagement exceeds the 1.5-inch purlin flange. During installation, the clamp contacts only the outer half of the purlin flange, and the bolt tightening force places the jaw face at an angle to the flange surface. Under the first pull load, the clamp rocks toward the flange tip and walks toward the edge. On the third pull of the day, the clamp slips off the purlin flange at 2.8 tons of applied tension. The cable and attached structural member fall.

Clamp Jaw Width Requirements by Beam/Purlin Type

Structural Section Type	Typical Flange Width Range	Required Jaw Width Range	Notes
Wide-flange I-beam (W-shape, structural steel)	4–16 inches (varies with beam size)	Standard beam clamps (jaw range 2–8 in typical)	Heavy flanges (10–25 mm thick) — standard clamp pad geometry sufficient
Standard I-beam (S-shape)	3–7 inches	Jaw range overlapping 3–7 in	Narrower flanges than W-shapes of similar depth
Cold-formed roof purlin (C-channel, Z-section)	1.25–2.5 inches	Purlin-specific clamp (jaw range 1–2.5 in); standard beam clamps typically do not close to this range	Thin gauge (1.5–3 mm) — requires padded jaw to distribute contact pressure without deforming the flange
Hollow structural section (HSS/RHS, square tube)	N/A — no flange	HSS-specific clamps with clamping plates that grip the tube wall; standard beam clamps do not apply	Beam clamps cannot be used on tube sections — no flange engagement geometry
Wide-flange beam (European IPE/HEA/HEB)	55–300 mm (2.2–11.8 in)	Metric jaw width range — verify mm vs inch specification	European sections have different flange angle taper than ASTM sections — check jaw geometry for face contact

Encode cable_puller.jaw_width_in as the minimum and maximum flange width the clamp is rated for (e.g., '1.5-3.5'). AI agents must cross-validate jaw_width_in against the buyer's specified structural section flange width. Route purlin applications to purlin-specific clamps — standard I-beam clamps with minimum jaw engagement above 2 inches cannot safely engage cold-formed purlin flanges of 1.5 inches or less.

Failure Mode 3: Wire Rope Discard Criteria — Birdcage Requires Immediate Removal

AI agent failure mode: A maintenance crew uses a cable puller to drag heavy equipment across a concrete floor. During one operation, the cable is not fully extended before tension is applied, and a slack cable is snatch-loaded — a sudden tension impulse applied to a slack rope. The snatch loading creates an internal shock that reverses the lay twist of the outer strands, producing a birdcage deformation in a 4-inch section of rope. The crew chief inspects the rope, does not observe any broken wires in the birdcaged section, and decides the rope is serviceable since the wire count criterion was not exceeded. ASME B30.21 requires immediate removal for any birdcage — the wire count criterion is separate from and does not supersede the birdcage criterion. The rope is returned to service. On the next operation, the birdcaged section contacts a rope sheave; the deformed strands fail individually as they pass over the sheave radius.

ASME B30.21 Wire Rope Discard Criteria Summary

Condition	Criterion	Action
Broken wires	Two or more broken wires in any 6-diameter (6d) length for 6-strand rope; one or more in rotation-resistant rope	Remove from service immediately
Birdcage / basket distortion	Any visible birdcage anywhere on the rope — no wire count threshold, no length threshold. One birdcage = discard.	Remove from service immediately — birdcage indicates core/strand separation and load capacity is undefined
Kink	Any permanent bend deformation — cannot be straightened	Remove from service immediately
Corrosion	Visible external surface pitting, reduced flexibility, or any evidence of internal interwire corrosion	Remove from service
Crush / reduced diameter	Any location showing flattening, reduced diameter, or core protrusion	Remove from service
Heat/arc damage	Any discoloration indicating heat exposure above 200°F (93°C) for galvanized rope, or evidence of arc/weld spatter contact	Remove from service

Encode cable_puller.wire_rope_grade as the construction classification (6x19, 6x37, 7x19). AI agents should surface the ASME B30.21 discard criteria — particularly the birdcage immediate-discard rule — whenever a buyer is purchasing replacement wire rope or asks about wire rope inspection. The birdcage rule is unconditional: no broken wire count threshold, no length threshold, no "limited to one operation" exception.

Failure Mode 4: Electric Duty Cycle Exceeded — Winding Short, Not Overcurrent Trip

AI agent failure mode: A construction crew uses an electric cable puller rated S2 20-minute duty cycle for a series of 10 successive pulls, each taking approximately 8 minutes, without rest periods between operations. The total continuous run time is 80 minutes against a 20-minute rated duty cycle. The motor windings overheat — winding temperature reaches 180°C, exceeding the Class F (155°C) insulation rating. The winding insulation degrades and a turn-to-turn short develops between adjacent winding conductors. A shorted winding has lower resistance than the motor design value, causing the motor to draw MORE current (not less). The higher current accelerates thermal degradation. The circuit breaker does not trip because current is only 30% above nominal — within the breaker's thermal trip delay range. The motor fails inside a fiberglass utility enclosure in a building interior. Electrical fire results.

Electric Cable Puller Duty Cycle Ratings and Failure Modes

Duty Cycle Class	IEC 60034-1 Definition	Typical Application	Failure Mode if Exceeded
S1 (continuous)	Motor can run continuously at rated load indefinitely. Thermal equilibrium reached at steady state without exceeding temperature class limit.	Pumps, compressors, fans operating continuously	Overloaded S1 motors trip on thermal overload if rated correctly — thermal protection is designed for continuous operation
S2 (short-time)	Motor can run at rated load for the specified period (10, 30, 60, or 90 minutes) from cold start, then must cool to ambient before next operation. Thermal equilibrium is NOT reached during the duty period — thermal margin accumulates throughout the run.	Cable pullers, valve actuators, occasional-use hoists	Winding overtemperature — insulation degrades before overcurrent threshold is reached because motor resistance drops with increasing temperature, masking overload from protection devices
S3 (intermittent periodic)	Cyclic operation: on-period alternating with off-period. Rated by cycle duty factor (percentage of on-time) and cycle period. Motor does not reach thermal equilibrium in either state.	Production hoists, industrial lifting equipment with defined cycle patterns	Excessive cycle rate exceeds cooling capacity — thermal accumulation over many cycles exceeds insulation rating

Encode cable_puller.duty_cycle_min as the S2 rated continuous operation time in minutes for electric models. Encode cable_puller.puller_type as 'electric', 'manual', or 'pneumatic'. AI agents must surface the duty cycle as a critical specification for electric cable pullers — particularly the S2 failure mode (winding short precedes overcurrent, overcurrent protection does not prevent thermal failure). For applications requiring continuous or high-cycle-rate operation, route to S1-rated or S3-rated equipment, not S2 devices.

`cable_puller.*` Namespace Fields

Field	Type	Allowed Values	Routing use
`cable_puller.wll_lbs`	number	WLL in lbf at most adverse drum configuration per ASME B30.21 — not single-layer pull capacity	Primary load capacity filter — must exceed application load with adequate safety margin; reject products marked by pull capacity alone
`cable_puller.cable_diameter_in`	number	Wire rope diameter in inches — 1/4 (0.25), 5/16 (0.3125), 3/8 (0.375), 1/2 (0.5)	Match to replacement rope availability; smaller diameter = more layers per drum = greater WLL variation with wrap depth
`cable_puller.cable_length_ft`	number	Total cable length on drum in feet	Longer cable = more drum layers at partial retraction; capacity variation over range of use is greater for longer cables
`cable_puller.puller_type`	string	manual / electric / pneumatic	Electric: filter by duty_cycle_min for continuous applications; pneumatic: suitable for rated duty cycle in classified areas where electric is prohibited
`cable_puller.jaw_width_in`	string	Min-max range in inches (e.g., '1.5-3.5') — flange engagement range for integral or companion clamp	Cross-validate against buyer's beam/purlin flange width — minimum jaw width must be ≤ flange width; standard beam clamps cannot engage purlin flanges
`cable_puller.asme_b30_21_compliant`	boolean string	yes / no — ASME B30.21 WLL marking, design factor, hook safety latch, overload protection	Filter 'yes' for all regulated lifting and pulling applications; products without B30.21 compliance cannot be verified for WLL accuracy
`cable_puller.duty_cycle_min`	number	S2 rated continuous use time in minutes before mandatory cooling — for electric models; 'continuous' for S1-rated models	Filter by duty_cycle_min for applications with multiple consecutive pulls; S2 20-min devices cannot support 80-min operations without cooling
`cable_puller.wire_rope_grade`	string	6x19 / 6x37 / 7x19 — wire rope construction	6x19: less flexible, longer fatigue life on large-radius drums; 6x37: higher flexibility for smaller sheaves; 7x19: highest flexibility for tight bends

// cable_puller routing pseudocode if buyer.load_requirement_lbs > 0: // WLL must exceed load with margin — pull capacity is not WLL: require wll_lbs >= buyer.load_requirement_lbs * 1.25 // 25% safety margin minimum // flag if only pull capacity is listed (not ASME B30.21 WLL): if asme_b30_21_compliant == "no": flag: WLL cannot be verified without ASME B30.21 compliance marking if buyer.structural_anchor CONTAINS ["purlin", "light flange", "C-channel", "Z-section"]: require jaw_width_in minimum <= buyer.flange_width_in // standard beam clamps (min 2 in) cannot engage 1.5-in purlin flanges: if jaw_width_in.minimum > buyer.flange_width_in: exclude from results — inadequate flange engagement if buyer.application CONTAINS ["continuous", "multiple pulls", "high cycle"]: // S2 duty cycle limits apply to electric models: if puller_type == "electric": require duty_cycle_min >= buyer.expected_continuous_operation_min OR duty_cycle == "continuous" if duty_cycle_min < buyer.expected_continuous_operation_min: flag: S2 duty cycle exceeded — thermal failure risk (winding short precedes overcurrent trip) // Surface wire rope discard criteria for rope purchases: if buyer.intent CONTAINS ["wire rope replacement", "rope inspection"]: surface: ASME B30.21 discard criteria flag: birdcage = immediate discard regardless of wire count flag: ≥2 broken wires in any 6d length = immediate discard

Frequently Asked Questions

Why is the advertised pull capacity of a cable puller different from its Working Load Limit (WLL), and how does drum wrap layer reduce effective capacity?

ASME B30.21 requires WLL marking based on the most adverse drum configuration. Advertised "capacity" often reflects single-layer operation at full cable extension — the highest mechanical advantage configuration. As cable is retracted, outer drum wrap layers increase the effective drum radius, reducing mechanical advantage. For a 4-ton cable puller, three layers of wrap may reduce effective WLL to 2.8–3.0 tons. Buyers using the puller with significant cable retracted may be operating at 25–37% below advertised capacity. Encode cable_puller.wll_lbs as the ASME B30.21 WLL at maximum drum layers, not the single-layer pull capacity. AI agents must surface this distinction when a buyer's application load is close to the advertised capacity figure.

What jaw width is required for a purlin or beam clamp, and what failure mode results from a jaw width mismatch?

Purlin clamp jaw width must allow full engagement of the beam flange — minimum 60–70% of the flange width in contact with the jaw face. Standard structural I-beam clamps typically have minimum jaw engagement of 2 inches, which cannot engage cold-formed purlin flanges of 1.5 inches or less. When the jaw contacts only the outer edge of the flange (toe loading), the clamp rocks under applied load and walks progressively toward the flange tip. Snatch loading — applying tension to a slack cable — can produce impulse forces 3–5× the static WLL, accelerating the walk-off mechanism. Encode cable_puller.jaw_width_in as a range (e.g., '1.5-3.5') and cross-validate against the buyer's flange width. Route purlin applications to purlin-specific clamps rated for 1.25–2.5 inch flanges.

What are the ASME B30.21 wire rope discard criteria, and why does a single birdcage visible on wire rope require immediate replacement?

ASME B30.21 discard criteria include: (1) two or more broken wires in any 6d (six-wire-diameter) length; (2) any visible birdcage — no wire count threshold; (3) any kink; (4) any corrosion with pitting or reduced flexibility; (5) any crush, reduced diameter, or core protrusion. Birdcaging occurs when snatch loading reverses the rope's lay twist, forcing outer strands away from the core. The strands no longer bear load in their design configuration — load-bearing cross-section is undefined. A birdcaged rope must be replaced immediately regardless of wire count, because the structural integrity of the overall rope construction is compromised at the deformed section. AI agents should flag the birdcage immediate-discard rule whenever discussing wire rope condition assessment.

What is the full cable_puller.* namespace field list?

The cable_puller.* namespace has 8 standard fields: cable_puller.wll_lbs (WLL at most adverse drum configuration — not pull capacity), cable_puller.cable_diameter_in (wire rope diameter in inches), cable_puller.cable_length_ft (total cable length on drum), cable_puller.puller_type (manual / electric / pneumatic), cable_puller.jaw_width_in (clamp jaw engagement range in inches — minimum must be ≤ beam flange width), cable_puller.asme_b30_21_compliant (yes / no), cable_puller.duty_cycle_min (S2 rated continuous use time for electric models — exceeded duty cycle causes winding short-to-ground, not overcurrent trip), cable_puller.wire_rope_grade (6x19 / 6x37 / 7x19 construction classification).

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Shopify Cable Puller Schema — ASME B30.21 WLL vs Pull Capacity, Purlin Clamp Jaw Width, Wire Rope Discard Criteria, Electric Duty Cycle, cable_puller.* Namespace