Electrical testing
Power-frequency withstand, lightning impulse, partial discharge, DC resistance, temperature rise, thermal cycling and power characteristics on fittings, cables and switchgear.
Electrical test scope
CNAS L7721 accredited · ILAC-MRA recognised
CNAS-accredited testing for HV/LV power system electrical equipment
The high voltage electrical testing centre of YONGU Group — an accredited laboratory covering power cables and wires, power fittings, cable accessories, insulators and surge arresters, and HV/LV electrical products: pole-mounted vacuum circuit breakers, disconnectors, load-break switches, fuses and pole-mounted substation assemblies. We test to IEC, GB and EN standards and issue English-language reports that hold up to utility specifications, tender requirements and customs review.
Accreditation & recognition
CNAS L7721
ISO/IEC 17025:2017
ILAC-MRA mutual recognition
Accredited since 2015
YONGU Group · since 1985
What we do
Five test disciplines, one accredited quality system
Six dedicated laboratories and one sample flow — from reception and identification through testing to report issue, under ISO/IEC 17025:2017.
Mechanical testing
Failing load, slip load, tensile and fatigue testing to the load defined in the standard — including a 600 kN servo-hydraulic horizontal tensile machine for long fittings.
Mechanical test scopeMaterial analysis
Chemical composition by OES, handheld XRF and SEM with EDS; metallography under a ZEISS microscope; coating mass and microstructure of aluminium and copper products.
Material test scopeAgeing & environment
Heat ageing in controlled ovens and xenon-arc ageing for insulation, sheath compounds and polymer components — the tests that decide service life in tropical and desert climates.
Ageing test scopeNDT & failure analysis
X-ray digital radiography, dye penetrant, ultrasonic and magnetic inspection — plus failure analysis after a claim, with a technical report suitable for negotiation or insurance.
NDT & analysisNot sure which test applies?
Send us the product drawing and the standard quoted in your tender. An engineer replies with a test plan, sample requirement, price and lead time within one working day.
Ask the laboratory
Why the reports are accepted
Evidence that survives scrutiny
For an export project, a test report is only useful if the buyer, the utility and the customs authority accept it. The laboratory is accredited by CNAS and its scope sits inside the ILAC Mutual Recognition Arrangement, so results travel.
- Testing accredited to ISO/IEC 17025:2017 under CNAS L7721
- Mutual recognition through CNAS as a signatory of ILAC-MRA
- English reports with clause-by-clause results and stated measurement uncertainty
- Instrument traceability held for every test in the report
- Online verification for every report number issued
- One named engineer per project, from enquiry to after-sales
Group backing
The laboratory belongs to YONGU Group, a manufacturer of transmission and distribution materials and HV/LV electrical products founded in 1985 — which is why the test benches, the metallurgy and the failure analysis are in house rather than outsourced.
1985
Group founded in Yueqing, Zhejiang
4
International standards co-authored
100+
Patents held by the group
2015
Year the laboratory was first accredited
The laboratory sits inside the manufacturer's technology centre, and is organised so that testing answers to the quality system, not to the sales department. What this means for the standing of a report is set out plainly on the accreditation page.
Lead times
Typical turnaround
Excluding sample transport. Express slots are available for tender deadlines — ask before you ship.
| Test package | Working days | Express |
|---|---|---|
| DC resistance & dimensional check (fittings, conductors) | 5 | 3 |
| LV cable routine tests (conductor resistance, dimensions, voltage test) | 7 | 5 |
| MV cable type test (partial discharge, 4 h voltage test, insulation thickness) | 12 | 9 |
| Mechanical failing load / slip load (fittings) | 7 | 5 |
| Temperature rise & thermal cycling (connectors, busbar) | 10 | 7 |
| Lightning impulse type test (switchgear, insulators) | 20 | 15 |
| Material composition & metallography | 7 | 5 |
| Heat ageing / xenon-arc ageing | Per standard cycle | — |
Turnaround starts when the sample and the confirmed test plan are both received. Ageing programmes run to the cycle defined in the applicable standard.
Products
What we test
The accredited scope covers roughly 200 test items across about 80 national standards, spanning power cables and line materials as well as high- and low-voltage electrical products. The families below account for most export projects.
| Product family | Main standards | Representative tests |
|---|---|---|
| Power cables & wires LV and MV XLPE / PVC power cable, ABC, bare conductors |
IEC 60502, IEC 60227, IEC 61089, GB/T 12706, GB/T 5023 | Conductor DC resistance, insulation thickness, partial discharge, AC withstand, ageing, flame propagation |
| Power fittings Tension & suspension clamps, connectors, line hardware |
IEC 61284, GB/T 2314, GB/T 14315, GB/T 9327, DL/T 2340 | Failing load, slip load, galvanising mass, metallography, DC resistance |
| Cable accessories LV and MV heat-shrink and cold-shrink terminations, joints, sealing ends, waterproof boxes (1–35 kV) |
IEC 60502, GB/T 12706, GB/T 9327 | Power-frequency withstand, partial discharge, thermal cycling, ageing |
| Insulators & arresters Composite and porcelain insulators, surge arresters |
IEC 61109, IEC 60099-4, GB/T 19519, GB/T 11032 | Power-frequency withstand, lightning impulse, mechanical failing load, ageing |
| HV switchgear & distribution apparatus Pole-mounted vacuum circuit breakers (10 & 35 kV, incl. primary-secondary integrated), disconnectors and earthing switches, load-break switches, HV fuses, enclosed switchgear, pole-mounted substation assemblies |
IEC 62271-1, IEC 62271-100, IEC 62271-102, IEC 62271-103, IEC 62271-200, IEC 60282-1, GB/T 11022, GB/T 1984, GB/T 1985, GB/T 3906, GB/T 15166 | Withstand voltage, lightning impulse, temperature rise, mechanical operation, short-time current, over-current |
| LV electrical products LV switchgear and controlgear assemblies, moulded-case and miniature circuit breakers, distribution boards and enclosures |
IEC 61439-1, IEC 60947-1, IEC 60947-2, IEC 60529, GB/T 7251.1, GB/T 14048.1, GB/T 14048.2 | Withstand voltage, temperature rise, mechanical operation, over-current, enclosure and IP checks |
| Copper & aluminium products Tube busbar, conductors, sheet and profiles |
IEC 61089, GB/T 3190, GB/T 5231, GB/T 5585 | Chemical composition, tensile strength, elongation, DC resistivity, dimensions |
The accredited schedule lists Chinese national (GB) standards; equivalent IEC and EN methods are carried out under the same quality system and are identified separately in the report.
How it works
From enquiry to report
1
Send the requirement
Product drawing or datasheet, the standard quoted by the buyer, quantity and deadline. Use the online enquiry form or email.
2
Confirm the test plan
We reply with the test items, sample quantity, price and lead time, and state clearly whether each item is inside the accredited scope.
3
Ship the sample
Mark the parcel as a test sample with no commercial value and quote the test plan number. Reception photographs and bar-codes the sample on arrival.
4
Testing and technical review
The sample is routed to the relevant laboratory. Every result is reviewed against the clause of the standard before the report is released.
5
Report and verification record
A signed PDF is issued first, followed by the original by courier. The report number resolves in the online verification tool.
Have a tender deadline?
Send us the standard and the sample list. We will tell you within one working day what can be done, how long it takes and what it costs.