The min bend radius isn’t that large in my experience. On the order of 10cm IIRC, possibly even less.

Even less is correct: outdoor fibers (G.652.D) have a minimum bend radius of about 30mm. The indoor counterpart (G.657.A1 and A2) have 10mm and 7.5mm.

The larger cables tend to have strength members with higher physical bend radius restrictions, i.e. you can't bend the steel or kevlar elements that tightly without breaking things.

Those are more of a technically no?

Like I have fiber to the house and you really need to pinch it and whatnot to cause an internet outage.

A small bend radius means it can have a tight bend.

A large bend radius means it has to be a big bend.

A 7.5mm bend radius is really small. You can bend that stuff pretty tight before you create a problem.

Much smaller than that, some might even say a utility box is overkill: https://old.reddit.com/r/techsupportgore/comments/nvwcuh/the...

Fiber’s perfectly happy being joined in 12” by 16” boxes for small runs. The terminal box in my garage has a few loops and is more like 6” x 8”.

https://www.seeclearfield.com/fiber-optic-wall-box/metal-wal...

Railroad minimum bend radius is orders of magnitude bigger than fiber's.