An electrical terminal size chart must distinguish the conductor end from the equipment end. Wire range describes what the barrel can terminate. Stud designation and hole dimensions describe a bolted attachment. Tab width and thickness describe a quick-disconnect interface. Matching only one of these dimensions does not establish a compatible connection.
The reference below uses identified manufacturer parts to show how those fields appear in real documentation. It is not a universal interchangeability chart or a TONFUL catalog. Use the examples to build a part-specific selection and inspection record, then obtain the selected supplier’s controlled drawing before ordering production material.
Jump to: Dimension map · Reference rows · Wire range · Stud checks · Tab checks · Verification
Electrical Terminal Size Chart: Read Three Independent Dimensions
Identify what each number measures
Wire size can appear as AWG, square millimeters or circular-mil area. These describe the conductor, not the insulation outside diameter and not the terminal’s installed envelope. A barrel inside diameter is another dimension; it cannot replace a documented wire range because conductor construction and crimp design also affect suitability.
For a ring terminal, the stud designation identifies the intended fastening interface. The actual opening needs clearance, so a nominal thread size and a hole dimension need not be numerically identical. Read the drawing’s hole callout and tolerance rather than treating a catalog label as a machining requirement.
For a receptacle, mating tab width and thickness describe the blade it accepts. The receptacle’s overall outside width is not the same dimension. Terminal stock thickness is also different from mating tab thickness: confusing those fields can produce a plausible-looking but incorrect purchase specification.
| Dimension group | Typical catalog fields | What it does not establish |
|---|---|---|
| Conductor end | AWG, mm2, strand compatibility | Current capacity of the completed circuit |
| Wire insulation | Permitted insulation diameter | Conductor area or sealing performance |
| Stud attachment | Stud designation, hole diameter | Hardware stack and tightening torque |
| Blade interface | Mating tab width and thickness | Compatibility with every same-width receptacle |
| Installed envelope | Length, tongue width, orientation | Tool access and wire bending clearance |
Keep product families separate
A ferrule has a metal sleeve intended for a compatible receiving terminal, not a ring eye or blade receptacle. Use TONFUL’s cord end terminal range when sleeve length and finished crimp envelope are the relevant questions. Do not enter a ferrule sleeve dimension into a stud-hole field simply because both measurements use millimeters.
Sourced Reference Rows for Wire, Stud and Tab Dimensions
Use these as identified examples, not equivalents
The following rows transcribe selected dimensional fields from TE Connectivity product documentation reviewed on October 17, 2026. Source identifiers refer to the named manufacturer part records. S1 is the TE 326878 ring-terminal product record. S2 is TE 130090; S3 is TE 60435-1. These parts are examples only: no TONFUL cross-reference, supply claim or interchangeability approval is implied.
| Source and exact part | Documented wire range | Stud designation and catalog diameter | Mating tab width x thickness |
|---|---|---|---|
| S1: TE 326878, PIDG closed ring | 22-16 AWG; catalog lists 0.326-1.31 mm2 | #6 / M3.5; 3.68 mm (0.145 in) | Not applicable |
| S2: TE 130090, PIDG closed ring | 16-14 AWG; catalog lists 1.04-2.62 mm2 | M5; 5.26 mm (0.207 in) | Not applicable |
| S3: TE 60435-1, FASTIN-FASTON receptacle | 20-16 AWG; 0.51-1.31 mm2 | Not applicable | 4.75 x 0.41 mm (0.187 x 0.016 in) |
For S1 and S2, the manufacturer labels the listed dimension “Stud Diameter.” Treat that as a catalog reference field; obtain the controlled drawing to confirm the actual opening callout, tolerance and permitted hardware. Do not change the source’s published field name into an unsupported universal hole tolerance.
The AWG and metric ranges above are reproduced as published, not recalculated as exact equivalents. In particular, catalog ranges and nominal AWG area conversions may not align intuitively. Do not silently correct the source or use its metric field to broaden an approved wire range. Resolve the selected conductor against the current drawing and application specification.
What the comparison actually demonstrates
S1 and S2 differ at both ends: wire range and stud attachment. S3 describes a different interface entirely. A buyer cannot select among these rows using a color or a single number such as “4.75 terminal.” State whether that number means wire area, stud opening or tab width.
The source records contain other product-specific information, but it has not been generalized here. No current, voltage, temperature, certification or pull-force value is transferred to another terminal. This table is a bounded dimensional reading aid, not an approval matrix.
Interpret Wire Range Without Turning It Into a Current Rating
Read conductor and insulation requirements together
Identify conductor material and construction before comparing size fields. A nominal area does not describe strand count, strand diameter, plating or insulation outside diameter. Fine-stranded and conventional stranded conductors can need different application guidance even when the printed nominal area matches.
For an insulated terminal, the wire must fit both the metal termination and the insulation entry or support arrangement. Review specific parts within TONFUL’s nylon-insulated terminal category using both requirements. A large insulation diameter must not be forced through an undersized sleeve or reduced by shaving the jacket.
Do not use red, blue or yellow as the primary purchasing specification. Color conventions vary by family and supplier, and color cannot identify stud size, tab thickness or compatible tooling. Keep the part number, drawing revision and conductor specification on the purchasing record.
Do not infer circuit capacity
AWG and mm2 identify conductor size; neither establishes a universal terminal current rating. Electrical suitability depends on the selected component and completed installation, including materials, contact interface, wire, ambient conditions and current duty. Engineering must assess those factors against applicable product and system documentation.
The same caution applies to two conductors in one barrel. Adding their nominal areas is not sufficient evidence that the terminal accepts the combination. Request the permitted combination and application instructions explicitly. A dimensional fit is only one part of compatibility.
Match Stud Holes and Fastening Clearances
Confirm the attachment rather than enlarging the part
Measure or obtain the equipment’s stud or screw specification, then compare it with the terminal drawing. Include tongue width, tongue thickness and the flat bearing area available beneath the specified hardware. A ring that passes over the stud can still interfere with an enclosure wall or fail to sit on the intended surface.
Do not drill, file or spread a terminal opening to create an improvised fit. Such changes alter the supplied geometry and may damage plating or reduce the material around the eye. Select a suitable part or request an engineering-approved alternative instead.
TONFUL’s non-insulated terminal category provides another product-family starting point where the surrounding design supplies insulation. The absence of a sleeve does not relax requirements for the fastening interface, protected conductive surfaces or controlled hardware.
Review the hardware stack and service access
Document the order of terminals, washers and nuts from the equipment instruction. Do not assume an unlimited number of lugs may be stacked on one stud. Check available thread engagement, seating, anti-rotation requirements and access for the specified tightening tool.
Use the equipment’s torque requirement where applicable, not a value selected from terminal color or nominal wire size. Ring geometry alone does not determine tightening torque. Perform dimensional checks and installation only on isolated equipment under the appropriate safe-work procedure; this chart is not live-work guidance.
Match Tab Width, Thickness and Mating Features
Width is only the first screen
A receptacle needs the specified tab width and thickness. A same-width blade with a different thickness can have unsuitable engagement or mating force. Check the full interface drawing, including any retention feature, insertion depth, housing requirement and orientation.
For S3, the documented tab interface is 4.75 by 0.41 mm. That is not permission to use every product marketed as a “187” receptacle, nor does it define a generic family tolerance. Compare the exact mating parts and their current drawings before approving a replacement.
Do not squeeze a receptacle with pliers to compensate for a loose fit or force an incompatible blade into it. An apparent improvement in hand feel is not a controlled dimensional or retention check. A fit problem should trigger review of part identity, damage and drawing compatibility.
Account for the completed assembly
Check the insulated envelope, wire exit, adjacent clearances and access needed to mate or remove the connection. A straight and a flag receptacle can share a blade size while requiring different installation space. The same terminal can also need different protective arrangements depending on the equipment location.
Tool compatibility remains a separate check. Ask TONFUL’s crimping-tool team about the exact terminal and conductor, not merely the tab size. The blade interface does not identify the crimp cavity or wire preparation.
Use a Dimensional Verification Record Before Release
Record actual evidence, not memory
Use the following record for sample review or receiving inspection. Engineering should define the measurement method, instrument suitability, sampling plan and acceptance document. The chart does not supply universal tolerances or sample quantities.
| Record field | Required entry |
|---|---|
| Identity | Supplier, exact part number, lot and drawing revision |
| Wire compatibility | Conductor specification and documented terminal range |
| Insulation fit | Wire outside diameter and permitted entry/support range |
| Equipment interface | Stud designation and opening callout, or tab width and thickness |
| Envelope | Length, width, orientation and service clearance |
| Measurement | Instrument ID, measured feature, result and applicable tolerance |
| Disposition | Accepted, held or rejected; reviewer and evidence reference |
Do not measure a formed opening at an arbitrary location and compare it with a drawing dimension taken elsewhere. Record the measurement location and condition, especially when a burr, plating or formed feature can affect the reading. Quarantine mixed or unidentified parts rather than sorting them by color alone.
Request the chart for the actual supply part
Send TONFUL’s wire-terminal sourcing team the conductor specification, equipment interface and available space. Request a controlled drawing showing the applicable wire range, stud opening or mating tab dimensions, insulation fit and overall envelope. Keep this article’s reference rows as reading examples, then release purchasing against the selected part’s own documents. That approach delivers a useful size chart without inventing TONFUL SKU dimensions or treating another manufacturer’s part as an approved substitute.