Exact component
Record OEM name, full catalog number, suffix, revision or date code when used, color, level count, link type and production site when it is a controlled field.
OEM engineering and supplier-quality guide
Terminal Block Sample Approval Checklist for OEM Projects
Approve the exact part, installed assembly and evidence package. A sample that looks right does not qualify another suffix, accessory set, approval condition, production site or future lot.
Freeze exact identityCatalog suffix, revision, site and accessory family stay in scope.
Build the real stackRail or PCB, wires, tools, markers and adjacent parts affect fit.
Keep evidence in contextA component approval is not finished-product approval.
Control future changeSample release must connect to lots, packaging and reapproval triggers.
Wire identification illustrates traceable panel work; the photo does not prove sample approval, terminal suitability or compliance. Photo: MTA Capital Construction Mega Projects / Wikimedia Commons, CC BY 2.0. Cropped and darkened for display.
Direct answer
Approve a defined system, not “a terminal block.”
Approve a sample only when the exact part, revision, accessory set, installation layout, conductor use and technical file match the controlled OEM design. The sample must fit the real rail or PCB. It must support the stated wire and work method. Its marks, packing and market evidence must also match the release file.
A visual pass is not enough. A passed unit does not prove that each future lot is the same. It does not qualify another catalog suffix, mold, plant, material, coating, tool or document revision.
Treat the sample as one part of a release system. Link it to a signed baseline, supplier change rules and incoming checks.
✓
Approve the exact item plus the full use condition and proof set.
Then state what a later shipment must match and which changes force review.
Then state what a later shipment must match and which changes force review.
Approval object
Write the full identity before inspecting the sample
Purchasing, design, quality and service must all be able to identify the same released item.
Exact circuit role
State feed-through, PE, fuse, test, disconnect, shield, multi-level, high-current, plug or PCB duty. A similar shell can hide a different role.
Exact build context
Freeze the rail or footprint, terminal order, end parts, bridges, covers, markers, duct relation and the wire family used at each point.
Exact revision set
Archive the live data sheet, size drawing, instructions, approval record, declaration and accessory catalog. Record the issue date or revision.
Exact sample link
Link the unit, pack label, lot or date mark, supplier, order and photos. Define which fields receiving staff must see on a later shipment.
Exact route to sale
List target nations, product class, customer rules and any Ex or other special use. Ask for proof that covers the exact item and use.
Do not call this PPAP unless the contract does.
Some OEMs use APQP or PPAP terms. Others use a first-article, sample release or supplier qualification file. Use the customer and quality-system language that applies. The evidence can be mapped across systems, but the names are not universal.
Evidence capture
Photograph the sample, label and installed row
Show each molded mark and printed tag. Include the pack label and any lot, date or plant code. Use enough views to record the clamp, rail foot, wire entry, levels, side wall and accessory ports.
Then build the real local stack. Show end clamps, end plates, dividers, bridges, test or fuse parts and markers. Include nearby duct, covers and the box door. A loose unit can pass while the row fails.
Store the files with the BOM and drawing revision. The terminal block specification guide gives a stable order for reading each data row.
Loose sampleShows the item and its own marks.
Built sampleShows fit, access and all linked parts.
Mechanical and process review
Build it with the real rail, wire and tools
Data-sheet dimensions are the start of the fit check, not the end.
Mount
Check the DIN rail or PCB fit, latch, direction, end restraint and row alignment. Use only the build shown in the item data.
Full envelope
Check pitch, width, height, depth, markers, covers, duct, door and spare rail space. Record the complete row length.
Wire approach
Use the real wire, end prep and bend path. Check entry angle, strip work, tool reach and view of the terminal ID.
Accessory stack
Fit each bridge, plate, cover, fuse, test part, plug, code and marker. Confirm the exact family and pole count.
Group bounds
Check gaps, surface paths, solid parts, PE groups and each safety or Ex boundary in the built row.
Work method
Use the stated strip length, torque or tool. Check that a trained worker can make and inspect the joint with no harm nearby.
Service access
Check marks, test points and all parts due for service. Do not approve a plan that needs unlisted tear-down.
PCB system
For a PCB part, freeze pitch, pins, footprint, board build, solder or press process, mating half and wire side.
Wire and electrical matrix
Tie each rating to the actual use row
Match the wire metal, solid or strand form, flex class, AWG or mm², bare or ferruled end and wire count. Use the exact strip, crimp and insert method. A ferrule can change the top size accepted by the block.
Record AC or DC use. Keep normal voltage, Ui where stated and Uimp apart. Record the current row, bridge or feed limit, nearby load, heat and any derating. Do not blend the largest values from IEC, UL or another approval table.
Keep current, short-time proof, SCCR and break rating in separate fields. A part value may depend on an upstream fuse or breaker. It does not replace the full panel review. For a deeper path check, use the guide to current rating versus actual load.
Use the actual wireDo not test with an easier shop sample.
Use the actual rowKeep each value with its stated terms.
Do not repeat product-standard type tests casually.
Use current reports and certificates to support the exact product. Add OEM fit, function and project checks where needed. High-voltage, short-circuit, temperature-rise or other destructive work belongs in a defined plan with qualified staff, suitable equipment, stated criteria and safe lab controls. This article is not a field test method.
Compliance and market file
A logo starts the check; it does not finish it
Archive the exact-model record, its scope and each condition used by the OEM review.
Approval record
Match catalog number, file or ID, category, ratings, use group and Conditions of Acceptability when they apply.
Correct layer
IEC 60947-7-1 and UL 1059 address component scope. The finished panel, machine or PCB still needs its own review.
RoHS and REACH
Get current, part-specific documents. Record date, scope and exemptions. Route substance issues to the OEM compliance owner.
Ex and other limits
Match the exact mark, certificate, approved parts, gaps and install terms. Do not infer scope from the base shell.
Declared construction
Freeze each controlled resin, metal, plating or flame class only to the degree required by the design and supply contract.
Live document set
Set rules for document age and new revisions. A PDF kept for years may no longer match the item or current market file.
Decision and gaps
Name who checks design, quality, supply and compliance. Record open issues, limits and approval with restrictions.
End-use suitability
Confirm spacing, wires, parts, protection, box and service terms in the real build. A component mark does not grant this result.
RoHS and REACH are live compliance areas.
The evidence needed depends on the product, market, supply-chain role and current substance rules. Keep the exact item, declaration date and scope together. Do not copy a statement from a related family without a direct link to the supplied part.
Accessory and row baseline
Freeze the parts that turn blocks into a system
List each bridge, feed-in, plate, divider, end clamp, cover, marker, plug, test part, fuse part and code key. State the exact part number and position. Do the same for PE and shield parts.
A bridge can set a lower current. A plate can be needed for touch or spacing. A revised pitch can make an old jumper wrong. A marker or cover can clash with duct or a service tool.
Keep the row plan and accessory BOM at one revision. Link them to a clear photo of the approved build. The terminal block accessories guide explains the roles of the main parts.
Exact partShape alone does not prove family fit.
Exact pointPosition can change the row function.
Sample-to-production workflow
Six stages link engineering approval to future lots
Sample count and test depth must follow risk, volume, contract, design age and supplier history. There is no universal number.
Engineering screen
Check the exact part on paper. Review wire, rating, function, geometry, parts and market needs. List each gap.
Physical sample fit
Build the real local row or PCB set. Check access, marks, wire work, parts and the work instruction.
Project checks
Run only the tests called for by the OEM plan. Link method, gear, unit ID, result and decision.
Approval baseline
Sign the list. Freeze photos, data, proof, row plan and BOM. Keep a physical or digital golden reference.
Production readiness
Set packing, marks, lot trace, site, no-change rules and incoming checks before the bulk order.
Incoming and change
Check later lots against the baseline. Hold any drift. Trigger review for each change named in the agreement.
Golden-reference boundary:
A retained unit shows the state that was accepted. It does not by itself prove process capability or lot consistency. Its value comes from clear identity, a duty to report change and a repeat check that links later stock to the same baseline.
Copy-ready release matrix
Record evidence, owner and decision in one place
Add the project criteria and document IDs before the form is used.
| Approval item | Required evidence | Release result |
|---|---|---|
| Project identity | Program, customer, drawing and BOM revision, supplier, OEM, exact part, suffix, role, market and reviewer. | Scope is clear and all groups refer to one item. |
| Sample trace | Sample ID, lot or date mark, pack label, photos, plant or origin when required, and data revision. | The unit can be tied to its record and later receipts. |
| Mechanical fit | Rail or PCB fit, row order, size, duct and door gap, end restraint, tool access, marks and service view. | The full local build fits and can be made as planned. |
| Wire and joint | Metal, strand form, size, end prep, strip value, tool or torque and work instruction. | The real wire set can be made and checked. |
| Functional parts | Bridge, plate, divider, marker, fuse or test part, PE or shield part, cover, plug and code. | All parts and positions match the released row. |
| Technical use | Voltage row, current path, heat, insulation, fault-duty owner and any special environment. | Each use condition has stated proof and an owner. |
| Market evidence | Approval IDs, certificates, declarations, RoHS or REACH file, scope, date and each exception. | Exact-item evidence meets the target market plan. |
| Test record | Risk basis, quantity, method, unit ID, gear, criteria, result, fault and corrective action. | The work is traceable and the decision is clear. |
| Production control | Golden reference, marks, pack, lot trace, site, change notice, reapproval triggers and incoming plan. | Future supply is tied to the approved state. |
| Final decision | Approved, approved with a stated limit, or not approved; named design, quality, supply and compliance sign-off. | No vague or open-ended sample approval remains. |
Common approval failures
Most errors come from approving too little
A family-level pass can hide a changed suffix. A loose sample can hide a bad row. A valid part record can still be used outside its terms. A good handpicked unit can still come from a weak bulk process.
Hold the item when the mark, pack, site, material, process, tool, approval, document or part set drifts from the baseline. Route the gap through the change plan. Do not let supply pressure turn a deviation into silent approval.
Use a formal terminal block cross-reference review when a new sample is meant to replace a released model. Replacement adds a direct old-versus-new comparison.
Approve enoughPart, row, file and supply state.
Hold each driftReview first; do not normalize it.
Six frequent failures
Shortcuts that weaken the release
Visual approval onlyLooks do not prove wire use, parts, ratings, proof scope or repeat build.
Family proof copied to a suffixThe suffix may change a function, metal, mark, fit or approval row.
Part approval treated as panel approvalThe end product and use terms still need their own check.
Loose unit passes; built row failsRail, duct, plates, bridges, marks and tools were left out.
Old files accepted with no date ruleMarks, substances, materials and certificates can change.
No supplier change noticeLater lots can drift in material, site, tool or process with no review.
Frequently asked questions
OEM terminal block sample approval FAQ
Use these as scope rules. Add the exact project criteria before release.
What should an OEM approve in a terminal block sample?
Approve the exact cataloged item and its stated build context: function, link type, accessories, rail or PCB layout, wire use, marks, data, market proof, packing and change terms. A bare unit is not enough when the row depends on linked parts.
Does a UL or IEC reference mean the complete OEM product is approved?
No. A component approval or standard reference is useful evidence. End-product fit still depends on the actual build, use conditions, equipment rules and market route. Keep the part proof and finish the OEM-level review.
How many terminal block samples should be tested?
There is no universal number. Set the count and test depth from safety risk, contract, volume, supplier history, design age, special approvals and any destructive work. Record why the chosen scope is enough.
Should the sample be checked with the OEM's actual wire and ferrules?
Yes, when wire fit or the work process is in scope. Use the stated metal, strand form, size, end prep, ferrule or lug, tool and instruction. Product type-test proof remains separate.
Are end plates, jumpers and markers part of sample approval?
Yes, when the design uses them. They can affect power links, group bounds, marks, service access and row size. Record each exact part and position in the approved BOM and sample build.
How should RoHS and REACH be checked for terminal blocks?
Request current, part-specific supplier documents. Keep the issue date and scope. Route each exemption or substance report to the OEM compliance owner. Do not copy a declaration from a related family.
When does a terminal block change require reapproval?
Review a change that can affect identity, fit, electrical role, approval terms, material file, plant, tool, process, pack or marks. Put the triggers in the supplier agreement before bulk release.
What is a golden sample for a terminal strip?
It is a controlled reference for the accepted state. It may be a built strip, sealed unit or photo and document pack. It must link to exact parts, linked parts, files and the signed decision. It does not prove all later lots are the same.
Related SENTOP guides
How to read terminal block specificationsSolid versus stranded wireCurrent rating versus actual loadTerminal block accessories guideFactory, inspection and delivery controlsPlug-in and PCB terminal blocksPrimary technical sources
- IEC 60947-7-1:2025 — component scope for copper-conductor terminal blocks and test-disconnect terminal blocks.
- UL 1059, Sixth Edition (2024) — terminal-block component scope and end-use boundary.
- UL component recognition and Conditions of Acceptability.
- European Commission RoHS overview.
- ECHA REACH supply-chain communication.
- Weidmüller terminal-block test context.
- Weidmüller Ex terminal-block guidance.
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