[Home](/)/[Resources](/resources)/Test Lab Engagement Guide test labEMC testingcertificationpre-compliance # How to Work with a Test Lab: Engagement, Pre-testing, and Managing Failures The relationship between hardware company and test laboratory is a significant determinant of compliance timeline and cost — and most hardware founders manage it poorly. Showing up with a product, booking test time, and hoping for the best is the most expensive approach. Structured pre-engagement, rigorous sample preparation, and a plan for failure scenarios make the difference between a clean campaign and a multi-month saga of retests and board revisions. Copy Link[Share on WhatsApp](https://wa.me/?text=https%3A%2F%2Fkrono-labs.com%2Fguides%2Ftest-lab-engagement-guide) [Plan my compliance campaign](/platform/new) Lab selection ## How to choose a test lab for your product and markets Lab selection is not primarily a price decision — it is an accreditation and capability decision. The primary qualification criteria are: accreditation scope (download the lab's accreditation schedule and verify every standard you need appears in the scope — a lab accredited for EN 55032 may not be accredited for ETSI radio standards or BIS CRS recognition for India); market coverage (some labs are optimized for EU/CE testing, others for FCC, some have multi-market capability to run both in a combined campaign); and product category experience. Booking lead times: for complex multi-standard campaigns, 8-12 weeks of lab lead time is not unusual. Book early — before your hardware is final. Some labs allow conditional bookings tied to hardware readiness dates. Lead times extend further during Q3-Q4 when companies rush year-end certification campaigns. Pre-engagement ## What to do before samples arrive at the lab The pre-engagement conversation — before any samples are shipped — is where most campaign time and cost is saved or lost. Cover these topics before the lab begins billing: standards scope review (provide your product description, block diagram, wireless capabilities, and target markets; ask the lab to produce a test scope summary listing every standard and test they plan to run); sample quantity and configuration (confirm how many samples are needed and what firmware version and operating mode represents worst-case for each test); and failure protocols (ask what their process is when a test fails — can you send a modified sample without restarting the full campaign queue?). Pre-compliance scan opportunity: ask if the lab can conduct a pre-compliance radiated scan of an early prototype before formal testing. A 2-4 hour scan session typically costs $1,000-$3,000 and can identify major emission peaks that would fail formal testing. Catching a 10 dB emission overshoot at pre-compliance is far cheaper than catching it on the first day of formal testing. Managing failures ## What to do when a test fails Test failures are normal — even well-designed products sometimes fail the first time. The key is managing the response efficiently. Get the failure data, not just the pass/fail result — a test report showing a failed emission limit should include the frequency, magnitude, and excess above the limit. This data determines whether a small component-level fix or a PCB revision is needed. Classify the failure as a design issue or a configuration issue first: some failures result from non-representative worst-case configurations that would not occur in normal use. Consider targeted retest vs. full retest: if you can make a targeted fix (add a filter, change a component value), a targeted retest of only the failed test may be possible without repeating the entire campaign. Discuss this with the lab before any changes are made. Document every design change in the technical file — the test report should reference the change, and the final technical file must clearly identify which product version was tested. If a board revision is required, accept that it adds a minimum of 4-8 weeks before retesting can begin. ## Learn this properly, not just for one product In-depth courses and books that teach the process — not a one-off answer you'll need to look up again next time. [Browse courses](/courses)[Free Compliance Roadmap](/platform/new) [Prefer to read? Get the book](/books) ## Frequently asked questions ### How far in advance should I book a test lab? For complex multi-standard campaigns (CE + FCC combined), book 8-12 weeks in advance of your target test start date. For simpler single-standard campaigns on small products, 4-6 weeks is often sufficient. Lead times are longer during Q3-Q4 as companies rush to complete certifications before year-end. If your hardware is not ready by the booked date, communicate with the lab as early as possible. ### What is pre-compliance testing and is it worth doing? Pre-compliance testing is informal testing of an early prototype to identify major EMC issues before formal testing. It uses measurement equipment similar to formal testing but without the accreditation rigor required for regulatory reports. It costs $1,000-$5,000 for a scan session vs. $15,000-$50,000 for a formal campaign. Finding a 10 dB emissions failure at pre-compliance costs a component change and a rescan — catching it during formal testing can cost weeks of delay and a board revision. ### Can I get my samples back after testing? Policies vary by lab. Most labs will return samples after formal testing, though test conditions may have subjected samples to electrical stress (ESD discharges, surge tests, elevated temperature) that reduces their reliability. Some tests are destructive by nature — battery crush tests, for example, destroy the test sample. Confirm sample disposition with the lab before shipping, especially for expensive prototype hardware. ### What documentation should I bring to a test lab? Bring: schematics and block diagrams; firmware version documentation matching the test samples; list of all operating modes the product supports; user manual or instruction leaflet; power supply specifications; and proposed compliance statements for user documentation. Some labs require this documentation before they will accept the booking. The more complete your documentation at the start, the more efficiently the test campaign runs. [ Map your product, free Every standard, document, and test that applies — free, no account required. Start mapping](/platform/new)[ Want an expert to handle your compliance for you? One consultant from Krono's compliance team takes your product from requirements to legal sale, with a fixed quote before any work starts. See compliance services](/services) Related guides * [OTA Testing for Wireless DevicesOver-the-air (OTA) testing measures the actual radiated performance of a wireless product in a controlled environment, accounti…](/guides/ota-testing-wireless) * [FCC TCB Certification ProcessFCC Certification through an accredited Telecommunications Certification Body (TCB) is mandatory for all intentional radiators.](/guides/fcc-tcb-process) * [CE Marking for Unintentional RadiatorsUnintentional radiators — digital devices that generate RF as a byproduct of operation — must comply with the EU EMC Directive.](/guides/ce-marking-unintentional-radiators) * [ETSI Standards for Wireless ProductsETSI (European Telecommunications Standards Institute) publishes the radio standards used for CE marking under the Radio Equipm…](/guides/etsi-standards-wireless) * [EN 62368-1 ExplainedEN 62368-1 (Audio/Video, IT and Communications Technology Equipment) replaced EN 60950-1 and EN 60065 in 2019 and is now the pr…](/guides/en-62368-1-explained) Educational resource only. Test lab capabilities, lead times, and pricing vary significantly. Obtain quotes from multiple accredited labs and verify accreditation scope before committing to a campaign.