Liushi, in Yueqing, Wenzhou, is the centre of China's low-voltage electrical industry — home to thousands of manufacturers producing breakers, contactors, relays, terminals and distribution equipment. That density is exactly why it is a great place to source from, and exactly why verification matters. Some factories are excellent. Some are trading companies with a workshop. Some are neither.
This is the checklist we use to verify a manufacturer before we place an order.
1. Legal identity
- Business licence (营业执照). Check the legal company name, unified social credit code, registered capital, established date, registered address and stated business scope. The scope should cover the manufacture of the product category, not just "trading" or "technology services".
- Registered address vs. actual address. These are often different — which is normal — but "actual" should mean a real production site, not a residential unit or a shared office.
- Legal representative. Confirm who signs, and that the person you are dealing with can commit the company.
2. Production capability
- Does it actually make the product? Ask which processes are in-house: injection moulding, metal stamping, coil winding, assembly, calibration, testing. A supplier that outsources everything is a trading company, which can still be fine — but the price should reflect it, and quality control is one step further away.
- Production lines and equipment. Ask for photographs or, better, a live video walkthrough of the specific line that will produce your order.
- Capacity. Can they handle your quantity and lead time alongside existing commitments? Ask what percentage of capacity your order represents.
3. Testing and quality control
- In-house test equipment. For electrical components, look for the ability to run routine tests — dielectric strength, contact resistance, trip-time verification, temperature rise. Ask to see the calibration records of the instruments.
- Incoming and outgoing inspection. Is there a documented incoming inspection for purchased parts (contacts, coils, plastics) and an outgoing inspection before packing?
- Traceability. Can they trace a finished device back to its production batch and the components used?
4. Certifications — and how to verify them
- Ask for the test report, not just a certificate. The report is the evidence; a certificate alone is a claim.
- Match the model exactly. Certificates are model-specific. Check that the model numbers and ratings on the certificate correspond to what you are ordering.
- Confirm the certificate holder. It should be the factory you are buying from, not an unrelated trading company.
- Verify independently. UL file numbers can be checked in the UL Product iQ database. Test report numbers from accredited laboratories (TÜV, SGS, Intertek, BV and similar) can be verified with the issuing laboratory.
- Check the CE Declaration of Conformity. It should list the applied standard — for example IEC/EN 60898-1 for an MCB — and be signed and dated.
Our guide to CE, UL and RoHS covers each mark in more detail, including the five-point check we run on documents.
5. Commercial track record
- Export experience. Which countries do they ship to, and do they understand the documentation and packaging those markets require?
- References. Ask for two or three existing customers, ideally in your region or market segment.
- Payment and terms behaviour. How do they handle a technical question or a quality complaint? The response during the sales process is a preview of the response when something goes wrong.
6. On-site verification
Documents can be prepared for a sales pitch. An on-site visit settles the questions that paperwork cannot:
- is the production line running, and with how many operators;
- is the warehouse holding real inventory of the components you need;
- is the finished goods area organised, labelled and traceable;
- does the test bench actually get used on production output.
We inspect at the factory before goods are packed. You can read more about this step on our How It Works page.
Red flags
- Certificate or licence images that are low-resolution, cropped, or show a different company name;
- reluctance to provide a live video walkthrough of production;
- prices dramatically below the market with no credible explanation;
- pressure to pay to a personal account rather than a company account;
- inability to explain basic technical parameters of their own product;
- a business scope limited to trading, presented as a manufacturer.
Verification is the job
Factory verification is a core part of what elechub.ls does. Before we quote, we confirm who actually makes the product, whether the certification covers your exact model, and whether the factory can meet your lead time. It is the least visible part of sourcing, and the part that most often determines whether an order goes well.
If you are evaluating suppliers for an electrical component order and want a second pair of eyes, send us the specification and the supplier details.