5 Costly Mistakes When Buying Cable Duct Seal
Most of the money lost on cable duct seals orders is not lost on price. It is lost on five repeatable mistakes that are all avoidable at the specification stage — before anything is made, shipped or claimed.
Mistake 1: Seal leaking around an oversized duct
the seal is sized for the duct nominal but the installed duct is outside tolerance, which is common with concrete ducts
How to avoid it: Put it in the specification, not in an email afterwards: the grade, the tolerance and the test that would have caught it.
Mistake 2: Cables migrating through the seal
no mechanical anchoring of the cable on the inner side; the seal is not a cable clamp
How to avoid it: Ask for the per-batch test record that proves the property in question — water tightness at pressure head; gas tightness — before the goods ship, not after they arrive.
Mistake 3: Treating every cable duct seal quotation as the same product
Suppliers legitimately differ on seal type (mechanical versus resin); duct and cable size range; fire rating. A quotation lower than the others usually means one of those levers was moved, not that the margin was thinner.
How to avoid it: Force every quotation onto the same one-page spec — EPDM seal; silicone for wide temperature range as the material basis — so the price spread means something.
Mistake 4: Ignoring packing and freight until the invoice
10 sets per carton with installation instructions. Packing is not an afterthought on this product: under-packed goods arrive as claims, and last-minute packing upgrades at the port cost several times the factory rate.
How to avoid it: State the packing and labelling in the RFQ and make it a priced line on the quotation, so the comparison is honest.
Mistake 5: Treating every cable duct seal quotation as the same product
Suppliers legitimately differ on seal type (mechanical versus resin); duct and cable size range; fire rating. A quotation lower than the others usually means one of those levers was moved, not that the margin was thinner.
How to avoid it: Force every quotation onto the same one-page spec — EPDM seal; silicone for wide temperature range as the material basis — so the price spread means something.
The one-page check before you place the order
- Grade and standard fixed on paper: EPDM seal; silicone for wide temperature range, to IEC 60529.
- Size range confirmed: duct diameter 50–200 mm, cable range 10–120 mm per port, single and multi-cable versions.
- Finish and coating stated: UV and ozone stabilised elastomer; metal plates galvanised or stainless.
- Test evidence agreed: water tightness at pressure head; gas tightness; fire resistance where rated.
- Packing priced as a line item: 10 sets per carton with installation instructions.
- Minimum order and lead time understood: 100 sets, 25–40 days.
Six lines, one page, zero of them optional. The suppliers who push back on any line are telling you where your order will go wrong — which is exactly the information you wanted for free.
Related: the supplier selection guide turns this checklist into ten interview questions, and the price guide explains which cost differences are real.
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Written for procurement teams sourcing from China. No account required to read anything in this section.
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