Creepage, Clearance, Dimensional & Construction Verification
ED&D creepage, clearance, dimensional, and construction verification tools support electrical product safety measurement and construction verification associated with IEC 60335, IEC 60601, IEC 60950, IEC 61010, UL 60950, UL 94, CSA 950, and EN 60950. This category includes feeler gauges, optical comparators, calipers, micrometers, mandrels, digital protractors, calibrated stop watches, and related fixtures used to verify spacing, thickness, geometry, angle, timing, and required constructional conditions prior to safety evaluation.
Tell us the product type, governing standard, and the feature or setup condition you need to verify, and we can help identify the right tool.
Verification Tools for Electrical Safety Spacing, Dimensions, and Construction Requirements
Safety measurement tools are used when the compliance question is not simply whether a part is present, but whether the distance, thickness, opening, angle, bend radius, material geometry, or construction condition actually meets the requirement. In product safety work, this commonly means verifying creepage distances, clearances, insulation thickness, hole size, trace spacing, fixture angle, timing duration, or the defined bending condition required before a follow-on safety evaluation.
ED&D’s safety measurement family combines several tool styles because no single instrument solves every verification problem. Fixed-dimension feeler gauges are useful when a pass/fail spacing check is needed quickly. Optical comparators are useful when the feature is too narrow, irregular, or difficult to access directly. Calipers and micrometers support broader dimensional work and insulation-thickness measurement. Protractors, stop watches, and mandrels support the controlled setup conditions many standards require before evaluating electrical or flammability performance.
These tools are used for work associated with IEC 60335, IEC 60601, IEC 61010, legacy IEC 60950 / UL 60950, CSA 950, EN 60950, and UL 94 workflows where spacing, dimensional, and construction checks remain central to the evaluation process.
Important standards note: a measurement or setup tool does not by itself “certify” a product to a standard. The correct tool, measuring method, orientation, setup condition, applicable clause, and engineering interpretation all matter.
How This Page Is Organized
- Spacing Tools: fixed-dimension feeler gauges for fast creepage and clearance checks
- Optical Comparators: comparator tools for narrow PCB traces, flex circuits, hole sizes, angles, radii, and small features
- Kit & Dimensional Tools: bundled comparator kits, calipers, and micrometers for broader dimensional verification
- Construction & Setup Verification: mandrels, digital protractors, and calibrated stop watches used to establish or verify defined test conditions
Spacing Tools for Creepage and Clearance Checks
CC-23 Feeler Gauge
CC-23 Feeler Gauge is designed for fast, repeatable measurement of creepage and clearance distances throughout electrical and electronic products. It is used to verify electrical spacings in office machines, data-processing equipment, medical equipment, power supplies, transformers, printed circuit boards, and other assemblies.
The set includes 23 individual gauge dimensions in millimeters: 1.0, 1.2, 1.4, 1.5, 1.6, 2.0, 2.4, 2.5, 2.8, 3.0, 3.2, 3.3, 3.5, 4.0, 4.5, 5.0, 5.6, 6.0, 6.3, 6.4, 6.5, 7.0, and 8.0.
Each gauge and the attachment ring are made of resilient hard stainless steel.
Used for work associated with IEC 60601, IEC 61010, and EN 61010.
Spacing-tool note: fixed feeler gauges are most useful when the engineer already knows the required dimension and needs a fast go/no-go style check in a tight or repetitive inspection workflow.
Optical Comparators for Narrow Features and Difficult Geometry
OC-20 Optical Comparator
OC-20 Optical Comparator is intended for narrow-feature measurement where direct contact tools are less effective, especially when evaluating creepage distances between PCB traces and spacing within flex circuits. The magnified reticle is used when the feature is visually small, difficult to access, or unsuitable for direct-contact measurement.
The OC-20 includes four commonly used reticles: 0.005 in/div, 0.1 mm/div, 1/64 in/div, and degrees/div.
Used for measurement work associated with IEC 61010 and EN 61010.
OC-1000 Deluxe Optical Comparator Gauge Set
OC-1000 Deluxe Optical Comparator Gauge Set is a 10x optical inspection kit. The 10x pocket optical comparator is used to inspect angles, thread measurements, hole sizes, radii, thickness, and narrow creepage or clearance distances on boards and flex circuits.
The set includes the 10x comparator, illuminator attachment, and nine interchangeable reticles, packaged in a wooden case.
Used for measurement work associated with IEC 61010.
Comparator note: optical comparators are used when the limiting feature is a narrow path, irregular contour, small opening, or trace geometry that is difficult to measure with direct-contact tools.
Kit-Based Measurement Systems and Supplemental Dimensional Tools
CCK-01 Optical Comparator Kit
CCK-01 Optical Comparator Kit combines four tools used for creepage and clearance measurement and supporting dimensional inspection in one package.
The kit includes: CC-23 Feeler Gauge, OC-20 Optical Comparator, DCP-01 Digital Calipers, and DMM-01 Digital Micrometer.
Used for measurement work associated with IEC 60335, IEC 60950, IEC 61010, UL 60950, CSA 950, and EN 60950.
DCP-01 Digital Calipers
DCP-01 Digital Calipers are used for general dimensional measurement of widths, openings, part dimensions, and other linear features.
Features include inch / millimeter conversion, hold, and floating zero functions. A case is provided.
Range: 0 to 6 in. / 0 to 150 mm
Resolution: 0.0005 in. / 0.01 mm
Accuracy: 0.001 in. / 0.03 mm
Included within the CCK-01 kit.
DMM-01 Digital Micrometer
DMM-01 Digital Micrometer is intended for higher-resolution dimensional work, including insulation thickness and other small material dimensions.
Features include hold and floating zero functions and a fitted case.
Range: 0 to 1 in. / 0 to 25 mm
Resolution: 0.00005 in. / 0.001 mm
Accuracy: 0.00005 in. / 0.001 mm
Used for work associated with IEC 61010, EN 61010, and UL 94.
Kit-selection note: the CCK-01 combines tools for fixed spacing checks, magnified trace inspection, general dimensional measurement, and insulation-thickness measurement.
Construction and Setup Verification Tools
CSW-01 Calibrated Stop Watch
CSW-01 Calibrated Stop Watch is used where a standard requires a defined timing duration or timed observation period during safety evaluation.
Timing features: Single Action, Time In / Time Out, and Continuous. Includes an audible SPLIT/LAP and START/STOP indicator.
Used for testing associated with UL 94.
PRO-360 Digital Protractor
PRO-360 Digital Protractor is a digital angle meter used where a test method calls for a defined burner, specimen, or fixture angle. It is used for burn-test angles and other defined setup conditions.
Features include hold to freeze the reading, resettable zero for comparison measurements, and a one-button calibration that restores factory accuracy without special tools on a relatively level surface.
Includes a 9 volt battery and hard plastic carrying case. Used for testing associated with UL 94.
MRL-01 Mandrel
MRL-01 Mandrel is used to test non-separable thin sheet material for constructional requirements related to protection against electric shock.
This is a defined bend-radius / forming fixture used to establish the required material condition before evaluating compliance with the applicable clause.
Used for IEC 60950:2005 Annex AA and IEC 60065:2005 Clause 8.22.
Setup-verification note: these tools establish required conditions such as time, angle, or bend radius that can affect the validity of the final safety evaluation.
Safety Measurement Tool Comparison
| Product | Primary Use | Application | Key Feature |
|---|---|---|---|
| CC-23 | Fixed spacing checks | Known creepage and clearance dimensions | Fast go/no-go style measurement with standard-relevant millimeter sizes |
| OC-20 | Narrow-feature optical inspection | PCB traces and flex-circuit spacing | Magnified reticle-based comparison for difficult-to-access features |
| OC-1000 | Expanded optical measurement | Angles, holes, radii, thickness, threads, narrow spacing | 10x comparator with illuminator and nine reticles |
| CCK-01 | Combined measurement kit | Labs needing multiple measurement methods in one package | Combines feeler gauge, comparator, calipers, and micrometer |
| DCP-01 | General dimensional checks | Openings, widths, part dimensions | Digital measurement with inch/mm conversion |
| DMM-01 | Precision thickness checks | Insulation thickness and other small dimensions | Higher-resolution digital measurement |
| CSW-01 | Timed test verification | Methods requiring defined timing or observation intervals | Calibrated timing functions with audible indicators |
| PRO-360 | Angle verification | Burn-test and fixture angle setup | Digital angle readout with hold, zero-reset, and one-button calibration |
| MRL-01 | Defined bend-radius conditioning | Constructional testing of non-separable thin sheet material | Establishes the required pre-test material condition for clause-specific verification |
Selection guidance: start with the feature or condition being verified. Use the CC-23 when the requirement is a known spacing value, the OC-20 or OC-1000 when the geometry is narrow or visually difficult, the CCK-01 when the lab needs a broader dimensional kit, and the PRO-360, CSW-01, or MRL-01 when the standard requires a defined setup condition before evaluation.
Frequently Asked Questions
What is the difference between creepage and clearance?
Clearance is the shortest distance through air between two conductive parts, while creepage is the shortest distance measured along the surface of an insulating material between those parts.
Why would a lab use a feeler gauge instead of calipers?
A feeler gauge is often faster when the required dimension is already known and the engineer wants to confirm whether a gap meets that value directly.
When is an optical comparator better than a direct-contact gauge?
It is better when the feature is very narrow, irregular, difficult to access, or located on a board or flex circuit where direct-contact measurement is awkward or less reliable.
Why are calipers and micrometers included in a creepage and clearance kit?
Because safety evaluation often includes more than one type of dimension. In addition to spacing, engineers may need to verify slot widths, wall thicknesses, openings, or insulation thickness as part of the construction review.
Why would a lab need a digital protractor, mandrel, or stop watch on a safety measurement page?
Because many standards require more than dimensional reading alone. Labs may need to verify a defined angle, a timed exposure or observation interval, or a specified bend radius before evaluating whether the product meets the safety requirement.
Can one tool handle every spacing and construction verification problem?
No. Straight gaps, narrow traces, irregular paths, insulation thickness, angle settings, timing intervals, and bend conditioning often require different tools.
Provide the governing standard and the measurement or setup requirement.
Typical Safety Measurement Applications
ED&D safety measurement tools are used in electrical safety laboratories, product certification programs, design verification workflows, construction review, PCB inspection, and component-level evaluation where creepage, clearance, insulation thickness, geometry, angle, timing, and pre-test material conditions must be verified.
Depending on the product family, these evaluations may be associated with IEC 60335, IEC 60601, IEC 61010, legacy IEC 60950, UL 60950, CSA 950, EN 60950, UL 94, and specific construction clauses such as IEC 60065:2005 Clause 8.22.
- Creepage and clearance checks on power supplies and transformers
- PCB trace-spacing inspection during safety review
- Flex-circuit spacing evaluation where features are visually small
- General dimensional verification of openings, slots, and part geometry
- Insulation-thickness measurement during construction analysis
- Angle and timing verification for flame-test or setup-sensitive procedures
- Defined bend-radius conditioning of sheet materials before shock-protection evaluation
- Legacy safety-file support where 60950-based spacing evaluations still appear in documentation
- Internal laboratory and third-party compliance evaluations
Method note: measurement results still depend on correct point selection, path definition, setup condition, and interpretation of the governing clause. Engineering judgment remains necessary when interpreting the result.