Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
ASME B107.20-2004 — Pliers: Lineman’s, Iron Worker’s, Gas, Glass, Fence, and Battery
🔧 ASME B107.20-2004 is the comprehensive standard in the ASME B107 hand-tool family covering lineman’s, iron worker’s, gas, glass, fence, and battery pliers — the basic tools of electrical, construction, municipal, and automotive maintenance trades. The Standard defines classification, dimensions, performance, and safety requirements for these six plier families, together with test methods such as the wire cut test and allowable permanent set requirements. Approved as an American National Standard on October 5, 2004, it supersedes ASME B107.20M-1998.
💡 Six plier families under one standard is typical of the “combined” sub-standards in the B107 system: they share a common construction, material, and test framework, distinguished by type and class to match jaw forms and applications.
1. Scope and General Framework 📌
The Standard covers the following six plier families:
- Lineman’s Pliers: standard electrical tool combining gripping, cutting, and crimping functions, optionally with insulated handles.
- Iron Worker’s Pliers: used in construction and structural steel work to grip, bend rebar, and tie wire.
- Gas Pliers: pipe-fitter’s pliers with multi-tooth gripping jaws for holding and turning pipe and fittings.
- Glass Pliers: cushioned-jaw pliers for gripping glass, mosaic, and other brittle materials with reduced breakage.
- Fence Pliers: multi-functional fencing tool combining gripping, wire cutting, nail pulling, and prying.
- Battery Pliers: battery-maintenance pliers whose jaw shape suits battery posts and cable terminals.
The Standard notes that Type II Hi-Leverage lineman’s pliers are not separately described because their requirements are the same as Type I. The 2004 revision relocated Type/Class/Style provisions into the design-requirements section and updated finish requirements and dimensional data.
⚠️ “Lineman’s pliers” do not automatically mean “insulated pliers”: B107.20 governs structure, dimensions, and mechanical performance. The voltage rating of insulated handles must be confirmed to the applicable electrical-safety standard separately. Live-line work requires certified insulated tools and voltage-class compliance.
2. Classification 🔩
The Standard classifies each family by type and class:
- Type I — Lineman’s: Class 1 Square Head, Class 2 Round Head, Class 3 Square Head with Wire Stripper.
- Type III — Iron Worker’s: Class 1 Square Head, Class 2 Round Head.
- Type IV — Combination Jaw: jaws combining flat and serrated gripping.
- Type V — Gas: pipe-form jaws.
- Type VI — Glass: cushioned jaws.
- Type VII — Fence: multi-function construction.
- Type VIII — Battery: terminal-gripping jaws.
Detailed dimensions for each family are given in Tables 1–6 in dual units (inch and metric series), covering overall length, jaw length, cutter length, and handle dimensions.
3. Technical Requirements and Specifications 📊
The Standard specifies dimensional and mechanical requirements; the core performance parameters are cutting capability and allowable permanent set. Typical parameters are shown below:
| Parameter | Typical Specifications | Remarks |
|---|---|---|
| Overall length | 6 in–12 in (152–305 mm) series | Lineman’s pliers typically 8 in/9 in |
| Jaw form | Square/round/stripper/combination/pipe/cushion/multi-function | Types I, III–VIII |
| Wire cut test | Wire sizes and test loads per Table 8 | Qualifies cutter performance |
| Allowable permanent set | Residual deformation limits after load per Table 7 | Qualifies body stiffness and strength |
| Finish | Rust protection; insulated handles optional | Insulation of lineman’s pliers separately certified |
Section 6 prescribes two types of tests: the Wire Cut Test, applying the wire sizes and test loads of Table 8 to the cutter to verify it cleanly severs the specified wire; and the Allowable Permanent Set Test (Table 7), measuring the residual deformation after a prescribed gripping load is removed, to ensure the pliers do not open up or distort excessively in service.
🚨 The cutter is designed for wire within its rated range. Cutting hard materials such as steel nails or spring wire beyond rating chips and rolls the edge, and flying fragments from a chipped cutter can injure eyes and hands.
4. Engineering Practice Essentials 🛠️
- 🔍 Select by job: lineman’s pliers for electrical work, gas pliers for piping, fence pliers for fencing; for multiple duties choose insulated-handle lineman’s pliers where certified.
- ⚠️ Electrical safety: verify the tool’s insulation rating against the working voltage before live work; inspect handles for damage and contamination; never work live with ordinary metal-exposed pliers.
- 🔧 Cutting technique: present wire perpendicular to the cutter and close to the joint pivot for maximum cutting force; avoid angled or repeated twisting cuts that damage the edge.
- 📋 Maintenance: clean filings and apply rust-preventive oil after use; periodically check cutters, joints, and insulated handles; keep the joint properly tensioned.
- 📅 Inspection: include pliers in routine tool checks, focusing on chipped cutters, misaligned jaws, and cracked insulation.
5. Frequently Asked Questions ❓
❓ Q: Can lineman’s pliers cut spring wire?
A: No. The cutter is designed for soft wire (see Table 8 test range); spring wire is too hard and will chip the edge. Use bolt cutters or carbide-edge cutters for hard wire.
A: No. The cutter is designed for soft wire (see Table 8 test range); spring wire is too hard and will chip the edge. Use bolt cutters or carbide-edge cutters for hard wire.
❓ Q: What distinguishes gas pliers from channel-lock pipe wrenches?
A: Gas pliers are fixed-hinge multi-tooth pipe pliers for a defined size range; channel-lock pliers have an adjustable sliding joint with adjustable opening. B107.20 covers the former; the latter falls under other wrench/plier standards.
A: Gas pliers are fixed-hinge multi-tooth pipe pliers for a defined size range; channel-lock pliers have an adjustable sliding joint with adjustable opening. B107.20 covers the former; the latter falls under other wrench/plier standards.
❓ Q: How long do insulated handles last?
A: Handles age, harden, and crack with use, and insulation performance degrades. Inspect on a defined schedule and periodically test per the electrical-safety code; stop live-line use once cracking, blistering, or delamination appears.
A: Handles age, harden, and crack with use, and insulation performance degrades. Inspect on a defined schedule and periodically test per the electrical-safety code; stop live-line use once cracking, blistering, or delamination appears.
🔍 Q: Manufacturers label plier sizes differently — what should I do?
A: Verify actual dimensions (overall length, jaw length, jaw form) against the B107.20 type-class-size framework, and state the standard designation plus complete naming in purchase documents so pliers from different makers meet the same performance requirements.
A: Verify actual dimensions (overall length, jaw length, jaw form) against the B107.20 type-class-size framework, and state the standard designation plus complete naming in purchase documents so pliers from different makers meet the same performance requirements.
