Terminal and Wire Connector Markings Guide
Read conductor material, wire range, strip length, temperature, and torque markings on electrical terminals and connectors before checking product instructions.
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Marking lookup
Use this page to interpret the information on a lug, terminal, splice connector, package, or equipment wiring label. It explains connection conditions. Functional numbers such as A1/A2 and 13/14 belong in the separate control-terminal reference.
| Marking | What it identifies | Next check |
|---|---|---|
| CU / copper only | Permitted conductor material | Check the connector’s own listing; the equipment may have different markings at different terminals. |
| AL / AL-CU / other material statement | A stated aluminum or copper application | Read the complete material statement, wire preparation, and any restrictions on mixing conductors. |
| AWG / kcmil range | The conductor sizes accepted at that terminal | Confirm solid/stranded construction, conductor count, and any separate ranges. |
| One / two conductor marking | The listed number and combination of conductors | A barrel that physically accepts two wires is not proof that two are permitted. |
| Temperature marking | A connector or terminal temperature limit | Do not substitute the conductor’s insulation rating for the equipment termination conditions. |
| Torque, with unit | The specified tightening requirement | Read the exact connection instructions and use the specified unit and tool method. |
| Strip length | Insulation removal length for that connector | Use the molded gauge or the exact product instructions; a visual estimate is not a specification. |
| Catalog / kit number | The identified connector or replacement terminal assembly | A connector fitting the mounting hole is not a replacement approval. |
| Wet / damp / sealing statement | An additional environmental use condition | Check the full assembly, seal, conductor combination, and enclosure requirements. |
Read the complete connection
- Identify the equipment and the terminal or connector catalog number. Retain its actual installation sheet.
- Compare the conductor material, size, stranding, and quantity with the permitted combination.
- Check the equipment marking as well as the connector marking. A connector rating alone does not establish the rating of the entire assembly.
- Locate preparation, stripping, tightening, inspection, and environmental instructions. Record the source with the job documentation.
For example, a hypothetical marking “CU, 14–10 AWG, 20 lb-in” communicates three separate limits. It does not establish the number of conductors or approve aluminum wire. The example is an interpretation exercise, not a torque specification to use on a real connector.
Torque units and instructions
Read lb-in, lb-ft, and N·m as different units. Copy both the value and the unit into a record. Do not carry a value over from another connector because the wire size looks the same.
Some connections use a specified torque; others use a spring mechanism or a crimp system with required tooling. A torque value for one kind of connection is not a procedure for the others. Follow the specified tool, die, preparation, and inspection method.
A record can capture the equipment, terminal identifier, conductor combination, instruction revision, required value and unit, actual work record, and tool identification. Use the test-record template or job card when those fields match the project’s record requirements.
Product-specific limits
The linked historical UL White Book explains marking conventions; it is not a current product approval. Confirm present listing information and the instructions shipped with the exact connector. Additional conditions can apply to service-side splices, parallel conductors, fine-stranded wire, and special environments.
This page intentionally has no universal AWG-to-torque chart, connector color interchange table, or instruction to retighten an existing connection. For conductor insulation and cable designations, use wire and cable markings.
Once the terminal conditions are known, use the ampacity calculator for its supported conductor-temperature, ambient and conductor-count checks. Its calculation does not establish connector compatibility or a tightening requirement.