In a past life, I specified some custom
cat5e wire for a particular application. We needed 12 miles total, to fabricate many hundreds of patch cables. I had the budget to pay a lab to test and certify the cable met specs.
Buying the 8 colored conductors from China, to twist, overmold and imprint here in the USA, was investigated in depth. Buying from China was finaincially very attractive.
From very knowledgeable cable experts, I heard many reasons why using wire from China wasn't a good idea. Some reasons have been mentioned here. I'll add another.
The quality often varies from batch to batch. Meaning I would have to send each different batch of cable out to the lab for testing. Or risk having problems in the field, after installs.
I chose to go with domestic sources. The prospect of variations in quality and performance was too scary.
That said, I use monoprice for my personal needs. I've been pleased with their cat5 and cat6 cables (spools and pre-made patch cables)
Fastb