A withstand-voltage row is not a drawing of the insulation paths inside a power supply. When an OEM asks about power supply creepage and clearance, the useful answer is revision-specific evidence showing what was assessed, under which requirements, and for which construction—not a distance estimated from a housing photograph.
The WEHO MDR-10-5 provides a concrete, conditional 5 V auxiliary-electronics example. Its authentic photographs and approved mechanical sheet establish the full model, envelope and terminal arrangement. They do not disclose internal creepage or clearance measurements. This guide does not assign those distances or claim an insulation certification for the unit.
Separate the two paths before requesting evidence
Texas Instruments’ creepage and clearance explanation distinguishes a surface-following insulation path from an air path between conductive parts. They describe different geometry. A view of a closed enclosure cannot establish either internal path, and an external terminal spacing cannot automatically stand in for every internal insulation boundary.
The official IEC 60664-1 publication description places clearance, creepage and solid-insulation criteria within insulation coordination for low-voltage equipment. It also identifies scope and environmental qualifications. Use the applicable product requirements and agreed edition with a competent safety engineer; do not reduce the assessment to a universal millimetre value copied from an unrelated design.
Illustrative indoor access-kiosk service bay: an MDR-10-5 supplies a conditional 5 V electronics interface. Its actual rear rail mount and supported front/right faces are represented; no hidden internal spacing is demonstrated by the scene.
Identify the insulation boundary being discussed
Ask the supplier to name the two circuits or conductive parts involved. Input-to-output, input-to-chassis and another internal boundary are not interchangeable descriptions. The record should identify the relevant construction and its assessed purpose, rather than giving one unexplained “clearance” number for the whole product.
A useful request also asks which applicable standard and revision govern the assessment, and which voltage and environmental assumptions were used. Where material, pollution, altitude or other conditions are relevant to the selected method, their approved basis should be traceable in the engineering file. This is a request for an assessment record, not an invitation to guess those conditions from an application photograph.
The OEM’s equipment environment should be supplied separately. A dry control bay in an illustration does not establish the pollution degree, installation category, approved altitude or protection of the delivered equipment. If these inputs are unresolved, preserve them as open questions and obtain the responsible engineer’s decision before treating the record as complete.
Do not translate a withstand test into a distance
A withstand-voltage statement concerns an electrical test under stated conditions. A creepage or clearance statement concerns construction and an applicable assessment. Keep both records when they are required, but do not invent a conversion between them. Neither an insulation-resistance row nor an external enclosure dimension supplies the missing internal path measurement.
This matters in purchasing conversations because the documents may look similar: each can carry a voltage, a standard reference and a pass result. Ask what the document actually covers. A full test report, construction drawing or assessment extract should identify its model and revision. A cropped table without that identity can leave a genuine evidence gap even when the numbers appear impressive.
Use the exact MDR-10-5 identity without rewriting the sample
The authentic side label identifies MODEL:MDR-10-5 and a nominal +5 V, 2.0 A output. The front face shows 5V/2.0A. The actual sample’s front frequency print is 47/63Hz, while its right label prints 50/60Hz; the images preserve each face as photographed. That difference is not silently corrected or interpreted as proof of a particular manufacturing revision.
The mechanical sheet gives a 22.5 mm front width, 90 mm upright height and 100 mm front-to-rear depth. Actual rear photographs support the rail hook and lower release latch. These are useful installation and identity facts. They do not establish the distances on the internal circuit board or through an unseen insulating structure.
A different microscope-automation controller uses an accepted 5 V auxiliary interface in a separate dry electrical bay. The supply is not assumed to power the microscope’s motion drive, and the arrangement is not an insulation test.
Before applying this model to a kiosk or controller, confirm the receiving interface’s allowed voltage and its documented load profile. Keep its protection, wiring and installation requirements in the equipment design. The model’s nominal output does not approve every 5 V device, and a small rail-mounted body does not prove an isolation class simply because it fits the cabinet.
Unchanged authentic MDR-10-5 source detail: the full model is on the right label, not an invented front label. The photograph preserves original trademarks, frequency printing, controls and terminal geometry.
Build a revision-specific evidence request
| Field | Evidence to request | Acceptance question |
|---|---|---|
| Product identity | Full model, construction revision and document identifier | Does the evidence apply to the purchased unit? |
| Boundary | Named circuits or conductive parts and assessed insulation purpose | Which path is actually being discussed? |
| Assessment basis | Applicable standard/edition and approved electrical/environmental inputs | Are the assumptions relevant to this equipment? |
| Construction evidence | Supplier-authorized drawing or assessment identifying the actual paths | Are creepage, clearance and solid insulation kept distinct? |
| Test relationship | Required electrical-test report linked to the same construction | Is a test result being mistaken for a geometric measurement? |
Where detailed internal drawings are confidential, agree an acceptable evidence route with the supplier and the responsible compliance engineer. An authorized assessment or report may be more appropriate than distributing design files. Do not open a mains-powered product or reconstruct internal spacing from photographs to fill a procurement record.
Documentary distinction only: surface path, air path and electrical-test evidence are different records. No internal MDR-10-5 geometry, distance threshold or certificate is invented in this diagram.
Control substitutions and construction changes
A replacement supply with the same output voltage is not automatically covered by the original insulation assessment. Ask whether the full model, construction or evidence revision changed and who reviewed the effect on the finished equipment. Preserve the decision with the purchasing record rather than carrying an old “approved” entry into a new BOM unnoticed.
Start a model inquiry with the WEHO MDR-10 family page, then request the current exact-model documents and the evidence appropriate to the intended installation. The goal is not to create a spacing claim from available pictures; it is to close the right evidence request before the design is accepted.
