How to Work With a Chinese CP Supplier: A Buyer's QC Checklist

1. Why Cathodic Protection Is a Special Purchasing Risk

Most imported equipment is bought against a specification you can inspect. Cathodic protection is different, because the anode is consumed to protect something you cannot see. If the anode is undersized, has the wrong alloy, or was made to a tolerance that does not suit the soil, there is no immediate failure. There is no customer complaint, no visible defect, and no recall. The structure simply corrodes faster than designed, and you find out years later.

This makes CP one of the categories where supplier discipline matters more than it does in ordinary mechanical purchasing. Three characteristics make it higher risk:

Failure is silent. An undersized or wrongly specified anode looks identical to a correct one when it arrives.

Everything is project-specific. Soil resistivity, the potential to be held, the protected surface area, the client's budget and the required service life all change the design. There is no "standard" anode for an arbitrary project.

Design confidentiality is normal. EPC companies and oil and gas operators frequently treat the cathodic protection design as confidential. A supplier who asks for the full drawing is normal; a supplier who insists on receiving nothing but cannot work from an approximate scope is not.

None of this means Chinese suppliers should be avoided. It means the relationship has to be managed differently, and this guide sets out exactly how.

2. The 12 Documents to Request Before Ordering

These are the items that a capable supplier can produce without difficulty. The order is deliberate: the first four prove the supplier is technically competent, the next four prove the product will be what you specified, and the last four protect your money and your schedule.

Technical competence — items 1 to 4

1. Alloy grade and certificate of analysis. What to ask: the alloy designation for each anode type, with a certificate of analysis traceable to the production lot. For magnesium anodes expect an alloy designation such as AZ31 or AZ63; for zinc, the specified grade; for aluminium, confirmation of the activating elements used. What it proves: that the supplier controls chemistry rather than melting whatever is available. This is the single most informative document in the whole list. Red flag: "Magnesium anode, high quality" with no alloy number. Repeat the same metal from two suppliers can deliver very different service lives.

2. Certified electrochemical capacity in Ah/kg. What to ask: the measured capacity in ampere-hours per kilogram, and the current efficiency. Request the test method or the reference to the standard used. What it proves: that the anode mass on the drawing will actually deliver the current required. The gap between theoretical and practical capacity is where disputes about anode lifetime come from. Red flag: the supplier quotes anode mass but cannot state the capacity. They may be designing to theoretical values, which means oversizing the anode and paying for metal that never protects anything.

3. Product drawing and specification sheet. What to ask: dimensional drawing, alloy, net mass, and any non-standard requirements from the project specification. What it proves: that the supplier will build to your project rather than to a stock item. Every CP component you buy should be traceable to a drawing, including junction boxes and reference electrodes. Red flag: it is completely normal for an EPC or operator to release the CP design only in part. A supplier who works confidently from an approximate scope and then confirms the critical parameters in writing is demonstrating experience, not a lack of information.

4. Standards and test certificates. What to ask: which standard each product is made to, and whether reports are issued to the standard named in your own project specification. Typical references include ASTM B843, B350 and B712 for anodes, and ISO 15589 or NACE and DNV codes for design and installation. What it proves: that the product will be accepted by your client's own inspection regime. Producing to a different standard than the one specified on your project is a common and expensive discovery made at customs or site acceptance. Red flag: a supplier who cannot name the standard they produce to, or who offers to "do the certificate later".

Product conformity — items 5 to 8

5. Manufacturing scope confirmation. What to ask: written confirmation of exactly what will be manufactured for you, and confirmation that the supply is made to order rather than pulled from stock. What it proves: that you and the supplier agree on the scope. Custom CP equipment takes different lead times per item — a junction box is not the same lead time as a cast anode — so the quotation must be itemised, not given as one lump figure. Red flag: ask specifically for the lead time to be confirmed per item. A single blanket "4 to 6 weeks" on an order containing junction boxes, rectifier cabinets and anodes usually means nobody has checked the critical path.

6. Packing specification and marking. What to ask: how items will be packed, marked and palletised, and whether any item requires special handling in transit. What it proves: that the goods will arrive identifiable and undamaged. In a multi-item CP order, unmarked or poorly segregated crates turn receiving into a guessing exercise. Red flag: confirm that each crate carries the project name, item number and drawing reference. It costs the supplier nothing and saves hours on site.

7. Third-party inspection access. What to ask: confirmation that your appointed inspector may attend at any stage, and that production will not ship before inspection is completed. Third-party inspection is available from SGS, BV, TUV and similar bodies. What it proves: that inspection rights are contractual, not a favour. A supplier who welcomes inspection has nothing to hide; a supplier who resists inspection is telling you what you need to know. Red flag: add to the contract: "production shall not be released for shipment before the buyer's appointed third-party inspection is completed." Without that sentence, an inspection right is theoretical.

8. Production progress reporting method. What to ask: how and how often you will be updated during manufacture, and whether photographs or video of the actual production will be shared. What it proves: that the order is being actively managed rather than sitting in a queue. For made-to-order equipment the period between deposit and production completion is where most schedule risk hides. Red flag: for long lead items, agree a written progress-update frequency at order stage, even if it is simply every two weeks. It costs the supplier very little and prevents the situation where you learn about a delay at the shipping deadline.

Protecting your money and schedule — items 9 to 12

9. Technical support and installation guidance. What to ask: whether the supplier will review your installation plan, comment on anode spacing and backfill, and provide guidance or supervision on site after delivery. What it proves: that the supplier is engineering-capable and prepared to stand behind the installation. Anodes that are correctly specified but incorrectly installed will underperform; a supplier willing to assist at the installation stage is protecting their own product. Red flag: for overseas projects, ask whether support is remote, on site, or both. Remote support during installation is normal and adequate for most cases; on-site supervision should be arranged and paid for separately.

10. Payment terms and cost breakdown. What to ask: the cost breakdown between material, tooling, packing, testing and freight, so you can see what you are paying for and where margin sits. What it proves: nothing. This item exists for both sides. A supplier willing to show a transparent breakdown is a supplier who is not hiding a quality compromise in the price. Red flag: typical terms in this industry: standard export terms such as T/T with a deposit and the balance before shipment, or an irrevocable L/C at sight. Terms are a function of trust and of the working capital required to make a custom product — they are not a judgement on your credibility. See Section 4.

11. Freight terms and nominated forwarder option. What to ask: whether the quotation is FOB, CIF or DDP, and whether you may nominate your own freight forwarder. What it proves: flexibility on your side of the logistics. Exporters who work with forwarders in the Gulf, Southeast Asia and Africa are used to customer-nominated shipping. Red flag: practical advice: compare freight on both bases. A supplier's own forwarder may be cheaper on some lanes and more expensive on others, and for project cargo the difference is not always in your favour.

12. Cast anode weight tolerance. What to ask: confirmation of the agreed deviation from nominal weight for cast anodes, the method of measurement, and on which units the tolerance applies. What it proves: that the supplier and the buyer have agreed on the practical acceptance criterion before production starts. Red flag: a tolerance of 5% or more without a defined method of measurement is a contract loophole. State the method (dry mass, surface-dry, saturated), the sample basis (per anode, per batch, per delivery), and the remedy if the tolerance is exceeded (replacement, weight credit, or rejection of the lot).

3. What Determines the Lead Time

Because cathodic protection equipment is made to order rather than pulled from stock, there is no single "standard" lead time that applies to a supplier. The date you are given is always a combination of the item type and your own project conditions. Rather than quote a figure that would not apply to your order, this guide sets out what actually moves the date.

The single most important thing a buyer can do is ask for the lead time to be confirmed per item, in writing, and to establish which item is on the critical path. A mixed CP order containing cast anodes, junction boxes, rectifier cabinets and reference electrodes will not move at the speed of its fastest component.

These are the factors that most often determine the delivered date:

Whether the item is cast, machined or fabricated. Cast items depend on alloy availability, mould availability and the batch size. Machined and fabricated items depend on the shop's current loading and on the availability of the specific material grade.

Design confirmation status. Time spent finalising drawings, approvals and revisions before production starts is time added to the schedule. Approving drawings promptly at the order stage is one of the cheapest ways to protect the delivery date.

Customisation level. Non-standard dimensions, terminal counts, cable entries, enclosure protection classes and labelling all require engineering and review time beyond a standard item.

Testing and certification requirements. Reports issued to a named standard, or to a specific client or third-party inspection body, add time that is easy to overlook because it happens after manufacturing.

Third-party inspection availability. The inspector must be booked at your factory. That booking sits between production completion and the ready-to-ship date, and the gap is often a week or more if it is not planned for in advance.

Packing method and shipping terms. Export packing, marking and documentation take time and are sometimes the last step to be completed.

Your own approval cycle. Client or consultant approval of drawings, inspection scope and shipping documents must be built into the schedule, because it depends on people outside the supply chain.

Two dates matter. Manufacturing completion and ready-to-ship are different milestones, and the gap between them is usually the inspection and documentation window. If your project schedule is tight, agree the inspection window before fixing the shipping date, not after. This is the most common reason a delivery date that was confirmed in advance still slips.

Ask in writing. Request a manufacturing completion date and a separate ready-to-ship date, together with the date third-party inspection is expected. A supplier who cannot separate the two has not established the critical path, and the slip will surface later on your side rather than theirs.

4. Payment Terms and Why They Are Set the Way They Are

Payment terms with custom manufacturers are mostly a function of working capital, and understanding this removes a lot of unnecessary suspicion in both directions.

For custom CP equipment the supplier must fund the full production cycle before anything ships. Material is bought first, then labour, then testing, then packing. On a made-to-order item — a junction box built to your terminal count and protection class, a rectifier cabinet built to your output rating, anodes cast to your mass — that work begins after the order is confirmed and paid. A supplier who accepts unsecured terms would be carrying your entire production cost plus the risk of non-payment for months.

Accordingly, the terms that are commonly accepted in this industry are:

Irrevocable L/C at sight — the most protective instrument for the buyer and fully acceptable to the supplier, since payment is made by an issuing bank against documents.

T/T with a deposit and the balance before shipment — a minimum deposit of about 30% on order, with the balance settled after production completion and inspection, before the goods are released.

Both are normal, both are widely used, and neither should be read as a lack of confidence in the buyer. What a supplier is saying by asking for them is simply: this is a made-to-order product, the costs are real, and we are not in a position to absorb the risk of non-payment.

If payment is an obstacle. A supplier who understands your position will usually propose a workable structure — a slightly different split, an L/C, or a staged payment against production milestones. A supplier who refuses to discuss terms at all has told you something more useful than a price comparison would have.

5. Quality Control: What to Confirm Before and After Shipment

5.1 Before production

Drawing approval in writing. Nothing goes into production without your written approval of the drawing or specification. Verbal approval is not approval.

Material confirmation at order stage. Alloy grade, capacity and standard written into the order acknowledgement.

Inspection access named in the contract. Appointment of SGS, BV, TUV or another body, with a stated inspection window.

Inspection scope agreed. Quantity, dimensions, alloy, appearance, and documentation review. Agree this in writing so the inspector is not left to interpret scope on arrival.

5.2 During production

Progress updates on an agreed frequency. With photographs from the factory where possible.

Video inspection on request. A live or recorded video of the actual production, not a stock video of someone else's workshop. It is a reasonable request and an experienced supplier will accept it.

Inspection report issued to you directly. The report should come from the inspection body with your name on it, not passed on informally by the factory.

5.3 Tolerances, and the one you should expect to discuss

Most CP components are machined or fabricated to defined dimensions, and tolerances are agreed and held. The item that commonly carries a tolerance is cast sacrificial anode weight. Casting process variation means the actual net mass of an anode can deviate from the nominal figure by a defined percentage, and the deviation is agreed between supplier and buyer in advance.

Worth negotiating early. A supplier who flags the cast weight tolerance before the order and proposes an agreed figure is being transparent. A supplier who says nothing and ships 5% under nominal mass has created a problem, because the structure is then under-protected by exactly that margin. Raise it yourself, early: confirm the acceptable deviation, and confirm how it is measured and on which units.

5.4 After delivery

Receiving inspection against the packing list and drawing. Count, dimensions, marking, and visible damage before signing the carrier's paperwork.

Retain certification. File the material certificates, inspection reports and shipping documents with the project records. They will be needed at handover.

Ask for installation support. Anode spacing, backfill preparation and reference electrode installation are the points where most installation errors occur. A supplier who will review your installation plan before you start is protecting the performance of the product they sold.

6. A Note on Protected Design Information

Some clients treat their cathodic protection design as confidential, which is entirely reasonable when the design reveals asset locations, protection strategy or operating parameters. This is worth addressing because it changes how a first conversation should go.

A capable supplier does not need your complete drawing to quote. What is needed is the approximate scope: the type of structure, the protected area, the soil or water environment, the required service life, the protection standard, and for accessories such as junction boxes the number of terminals and the required enclosure protection class. From that scope, a supplier can propose a design and confirm the critical parameters back to you in writing before anything is ordered.

What you should get in return, before payment, is written agreement on the parameters that cannot be guessed: alloy grade, certified capacity, the protection standard, dimensional basis and the accepted weight tolerance for cast anodes. That combination — approximate scope from you, written parameter confirmation from the supplier — is a legitimate basis for ordering, and is how most real international CP projects proceed.