Technical Answers
15 questions clients have actually asked. The first paragraph of each page is the answer itself.
These are the questions clients actually ask us, and ask most often. The first paragraph of every page is the answer itself — no preamble, because most people (and most AI engines) read only the first three lines.
The questions fall into two groups: selection and decisions — whether to test and how to choose; and standards and technique — what a given standard says and how a given test is run. The first group is about judgement criteria, the second about technical definitions.
If your question is not covered, send it to an engineer directly; frequently asked ones get written up as a page.
Choosing a supplier
The questions clients search when comparing suppliers. The answer explains how to judge, not why to choose us.
Which institution should I use for automotive EMC testing?
Check three things first: whether your EMC items sit inside the CMA / CNAS scope of accreditation, whether the anechoic chamber and test equipment are in-house, and whether the lab can run the full CISPR 25 and ISO 11452 set. Talk about price only after those three pass — the cost of one re-run usually exceeds the difference.
Recommended environmental reliability testing laboratories
Environmental reliability is not one test but a family of tests. Do not start from "which laboratory" — first break your scope down by mounting location and acceptance standard, then check whether the chamber volume, shaker force rating and salt spray cabinet size can accommodate your samples. Samples exceeding equipment capability are the main cause of re-runs on this type of project.
Which third-party laboratories are CNAS accredited?
Do not judge CNAS accreditation from a brochure. Go to the CNAS website and search the register of accredited bodies by organisation name or certificate number. Check two things: whether the certificate is still valid, and whether your specific test item appears in the scope of accreditation. Holding a certificate does not mean the scope covers your item — that is a very common misjudgement.
What reliability tests do connectors need?
Connector reliability splits into four lines: electrical (contact resistance, insulation resistance, dielectric withstand), mechanical (insertion and extraction force, terminal retention, vibration), environmental (temperature-humidity cycling, salt mist, thermal shock) and material (plating thickness, flame retardancy). Real projects take a subset per the customer standard. Vibration combined with terminal fretting corrosion is the failure mode that most often goes wrong in automotive use.
What environmental tests do automotive parts need?
Define the test items by mounting location, not by part name. Engine bay, body, chassis and passenger cabin see completely different temperature, vibration and ingress loads. Fix the mounting location first, look up the severity parameters in the corresponding part of ISO 16750 / GB/T 28046, then layer the OEM corporate standard on top — that makes an executable test list.
Vibration and shock testing laboratories
Look at three things only: whether the shaker's force rating and table size can take your sample plus fixture, whether combined temperature-vibration testing is available, and which spectral profiles the controller supports. The combined weight of sample plus fixture exceeding the table rating is the most common cause of re-work — fixtures often weigh as much as or more than the sample.
Salt spray testing institutions
First work out which type of salt mist you need: neutral (NSS), acetic acid (AASS), copper-accelerated acetic acid (CASS) or cyclic. The solution, temperature and acceptance basis differ for all four, so confirm the laboratory runs the type your customer specified, and that the cabinet volume can accommodate your samples.
How to choose a third-party testing laboratory
Check five hard criteria in order: whether the scope of accreditation covers your specific item, whether the key equipment is in-house, whether your sample dimensions are within equipment capability, whether the report will be accepted by your customer or regulator, and whether anomalous data is reported proactively. Price comes after these five — one re-run usually costs more than the difference.
Who should carry out PCBA failure analysis?
Two things matter: whether the laboratory has both non-destructive and destructive analysis methods (X-ray, CT, C-SAM, dye penetrant, cross-section, SEM/EDS), and whether it can deliver a failure mechanism judgement rather than photographs alone. A laboratory with only X-ray and no cross-section or composition analysis usually never reaches the root cause.
What testing and certification does the EU require for automotive electronics?
Three workstreams run in parallel: EMC through ECE R10 type approval, or CISPR 25 / ISO 11452 where the customer requires component-level validation; environmental compliance through RoHS and REACH; and RED on top for products with wireless functions. Test reports are only one part — compliance also needs a technical file and a declaration of conformity.
Standards and technique
The questions engineers search when reading a standard or scoping a test. The answer has to be precise enough to be quoted directly.
What is ISO 16750-2?
ISO 16750-2 is part 2 of ISO 16750 and specifies the electrical load tests for electrical and electronic equipment in road vehicles, covering the DC supply voltage range, overvoltage, superimposed alternating voltage, voltage dip and recovery, reverse voltage, ground offset, open circuit and short circuit. Abnormalities in the vehicle power supply are largely covered by this part.
CISPR 25 vs ISO 11452: what is the difference?
Both govern automotive EMC but point in opposite directions. CISPR 25 covers emissions — the limits on interference a product radiates and conducts outwards. ISO 11452 covers immunity — the test methods for applying interference from outside. Certification needs both: one tests that you do not disturb others, the other that you survive when others disturb you.
Vibration testing vs mechanical shock testing
Vibration is a continuous, repeated load that tests fatigue and resonance; shock is a single, transient, high-acceleration load that tests structural strength and instantaneous failure. Neither replaces the other — many products pass vibration and then fail shock, because the failure mechanisms are completely different.
How long does a salt spray test need to run to pass?
Test duration is set by the reference standard and there is no universal figure: neutral salt mist commonly uses fixed hour bands (for example 24, 48, 96, 240, 480 or 720 hours), while cyclic salt mist is counted as cycles × duration per cycle. Passing is not about how long you ran — it is about whether base metal corrosion, blistering or plating loss appeared afterwards, with the acceptance limits set by the standard or the customer.
How to fix a product that failed EMC testing
Locate before you modify: establish whether it is an emission overrun or an immunity failure, which frequency band it sits in, and which path it escapes by (radiated through space, conducted along cables, or through the supply). Then fix it specifically — conducted problems call for filtering and grounding, radiated problems for shielding, routing and seams, immunity problems for TVS and filter networks. Modifying the board without locating first usually takes several rounds.
Not found what you were looking for? Send us the question — an engineer replies directly, and frequently asked ones get written up as a page.
Have a testing requirement? Send us your product details
Tell us the product model and test requirements. Our engineers will map out the test plan, the applicable standards and the item combination, and provide a quotation reference. The more specific the request, the sharper the answer.
- Free scoping of the test plan and standards
- Pre-scan testing during R&D to cut rework cost
- On-site visits and witnessed testing supported
- Scheduling per project, with progress updates at each milestone
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