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ASME B107.27-2003 — Pliers: Multiple Position, Electrical Connector
🔌 ASME B107.27-2003 is the American National Standard dedicated to multiple position electrical connector pliers, commonly known as “Cannon Plug Pliers.” These tools are used primarily for connecting or disconnecting the threaded lock collars of electrical connectors. Their application centers on aerospace, defense, telecommunications, and industrial electrical work, where connector lock collars require adequate tightening torque yet must not be marred. Equipped with jaw sleeves or inserts, these pliers grip the collar firmly without damaging its finish. The 2003 edition revises B107.27-1996, consolidating the Type and Class classification, referencing the performance test methods in B107.25M-1996, and updating references. It was approved as an American National Standard on May 1, 2003.
💡 The design philosophy of electrical connector pliers is “grip, turn, don’t mar”: the jaw sleeves prevent scratches on the lock collar, and multiple adjustment positions adapt the tool to connectors of different diameters.
1. Scope and Positioning 📌
This Standard provides performance and safety requirements for pliers used primarily for connecting or disconnecting the threaded lock collars of electrical connectors. It defines dimensional data and requirements for strength, durability, and ease of operation. As with other B107 standards, inclusion of dimensional data does not mean that all products described are stock production sizes — consumers should consult manufacturers for stock size lists. The Standard may also be used as a guide by state authorities or regulatory bodies in formulating regulations and is intended for voluntary use by establishments that use or manufacture the tools covered.
⚠️ B107.27 applies to pliers dedicated to electrical connector lock collars, not to general-purpose pliers. For ordinary bolts, nuts, or water pipes, choose B107.23 multiple position adjustable pliers or the appropriate wrench standard rather than misusing a specialized tool.
2. Design Requirements and Jaw Capacity 🔩
Section 5 of the Standard specifies the following design requirements:
- Function: pliers shall be suitable for loosening and tightening threaded lock collars of electrical connectors, with all parts properly proportioned for strength, durability, and ease of operation.
- Jaw sleeves/inserts: shall be used to prevent marring of the gripping surface of collars.
- Jaw capacity: jaw capacity shall be adjustable through a range of 0.75 in to 2.5 in to accommodate collars of different diameters.
- Dimensional requirements: pliers shall meet the dimensions of Fig. 1 (minimum capacity position) and Fig. 2 (maximum capacity position) and pass all tests in Section 6.
| Design Requirement | Details | Purpose |
|---|---|---|
| Jaw sleeve/insert | Protective sleeve fitted inside the jaws | Prevents scratching of the collar surface |
| Multiple position adjustment | 0.75 in to 2.5 in range | Adapts to connectors of various sizes |
| Overall proportioning | Strong, durable, easy to operate | Transmits tightening torque reliably over life |
| Release mechanism | Facilitates one-hand operation | Improves productivity and reduces fatigue |
3. Material, Finish, and Marking 🛡️
Materials used in manufacturing must produce pliers conforming to this Standard. Surfaces shall have a rust-preventive treatment and be essentially free from pits, nodules, burrs, cracks, and other conditions that would adversely affect the performance or safety of the tool. Where coatings are provided, they shall be adherent, smooth, and continuous, free from conditions that would interfere with their protective value, safety, and function. For marking, pliers shall be marked in a plain and permanent manner with the manufacturer’s name or trademark, and size/designation information as specified, ensuring traceability.
🚨 The jaw sleeve/insert is the key to protecting the collar surface from scratches and is also a wear item. If a sleeve is worn, cracked, or missing, replace it immediately; never grip an electrical connector without the sleeve, as this can damage the collar plating and impair the connector’s sealing and electrical performance.
4. Hardness and Test Methods 🧪
The jaw sleeve insert is evaluated per the “Jaw Sleeve Insert Test” (Fig. 3) in Section 6. The test uses durometer hardness per ASTM D2240 (Test Method for Rubber Property — Durometer Hardness) or an equivalent method to evaluate the hardness and resilience of the sleeve material, ensuring adequate cushioning and protection during gripping. For overall performance, pliers are tested to the handle load and functional methods of B107.25M-1996, Pliers — Performance Test Methods. The Standard also requires pliers to pass all tests in Section 6 without cracking or breaking.
| Test Item | Method Reference | Acceptance Focus |
|---|---|---|
| Jaw sleeve insert test | ASTM D2240 durometer hardness | Material hardness/resilience meets requirements |
| Handle load test | B107.25M-1996 | No cracking; permanent set acceptable |
| Jaw capacity check | Fig. 1/Fig. 2 dimensions | Adjustable over the full 0.75–2.5 in range |
| Visual and marking check | Visual examination | No defects; clear permanent marking |
5. Engineering Practice Essentials 🛠️
- 🔍 Selection: measure the outside diameter of the connector lock collar to confirm it falls within the 0.75–2.5 in adjustment range, then choose the length and grip that suit the task.
- 🔧 Use: seat the jaw sleeves against the collar circumference before turning; follow the connector marking and process documents for pre-tightening and final tightening direction (usually clockwise), and never force the collar against the thread.
- 📋 Maintenance: clean the jaw sleeves and check for wear after each use; lightly lubricate pivot areas to prevent corrosion and binding.
- 📊 Procurement: verify the manufacturer’s mark and size designation, request a statement of conformance, and sample test with a load test per B107.25M if required.
6. Frequently Asked Questions ❓
❓ Q: Why must electrical connector pliers have jaw sleeves?
A: Connector lock collars are usually plated or anodized. Direct metal gripping scratches the surface, degrading sealing, corrosion resistance, and electrical contact. Jaw sleeves provide a soft gripping face that prevents damage.
A: Connector lock collars are usually plated or anodized. Direct metal gripping scratches the surface, degrading sealing, corrosion resistance, and electrical contact. Jaw sleeves provide a soft gripping face that prevents damage.
❓ Q: What connectors does the 0.75–2.5 in range cover?
A: It covers common sizes from small circular connectors (about a 3/4 in collar) up to larger connectors (about 2.5 in). Connectors beyond that range need dedicated large pliers or special fixtures.
A: It covers common sizes from small circular connectors (about a 3/4 in collar) up to larger connectors (about 2.5 in). Connectors beyond that range need dedicated large pliers or special fixtures.
🔍 Q: Can ordinary water pump pliers replace electrical connector pliers?
A: Not recommended. Ordinary pliers with serrated jaws or without sleeves easily scratch the collar, and their grip geometry and torque control are unsuitable. Use dedicated pliers conforming to B107.27.
A: Not recommended. Ordinary pliers with serrated jaws or without sleeves easily scratch the collar, and their grip geometry and torque control are unsuitable. Use dedicated pliers conforming to B107.27.
❓ Q: Does the Standard specify a tightening torque value?
A: B107.27 specifies the pliers’ own performance and safety requirements, not the connector lock torque — that value comes from the connector product specification or the user’s process documents. The pliers must operate reliably without slipping within that torque range.
A: B107.27 specifies the pliers’ own performance and safety requirements, not the connector lock torque — that value comes from the connector product specification or the user’s process documents. The pliers must operate reliably without slipping within that torque range.
