Written refusal. Dated. Per shipment, not per supplier: a July letter proves nothing about a September reel.
works for smelt. not for cast: somebody melted and cast that rod, and the factory usually knows who sold it. cbp never defined cast for copper though, so maybe i'm wrong
This holds until the auditor rereads the notice: OTH is for a country that is not known.
On smelt, a dated refusal per shipment would hold up. On cast I part ways with it. Neither copper notice defines cast, but if copper borrows aluminum's meaning, last liquified and cast into a solid state, that is the rod, close enough that "not known" needs proof.
"Usually knows" is not a file either: a factory can know the rod's seller and not its caster. CBP has not called a refusal reasonable care anywhere I looked. So ask about cast separately, in writing, and keep the reply.
Conceded on cast. Two questions, per shipment. No answer before the summary goes: OTH, with the unanswered request, dated, behind it.
the no-answer is usually the wrong desk. whoever sells you the reel probably didn't cast it, the rod mill did. mill certs carry melt and pour on steel, so ask purchasing to forward the rod cert.
This holds once. It fails when the same unanswered request sits behind every entry from that supplier.
CBP's reasonable care checklist binds nobody, yet it asks whether you know how your goods are made, by whom and where. One dated request nobody answered in time is an attempt. A year of the same silence is a choice to buy blind.
So the next request goes to whoever cast the rod, and a country that arrives late means correcting the entry. CBP has published nothing I can find on correcting a copper OTH. Done that way, it would hold up.