Cable in which bare 250 µm fibers sit loose inside buffer tubes, usually 12 fibers per tube, stranded around a central strength member. The fibers have slight excess length, so the cable can stretch under pulling tension or shrink in the cold without loading the glass. Tubes are either gel-filled or kept dry with water-swellable tape and yarn, and the fibers are normally spliced to pigtails rather than terminated directly.
Feeder is a 288-count loose-tube, twenty-four tubes of twelve, so plan two full days in the closure.
Indoors, loose-tube outdoor cable usually has to transition to rated indoor cable within about 15 m of the building entrance, because its polyethylene jacket does not meet indoor fire ratings.
Also heard as
- loose buffer cable
Do not mix it up with
- Tight-buffered cable: Tight-buffered cable is an indoor design with a 900 µm buffer on every fiber, terminated directly.
Related terms
Buffer
The protective plastic layer or tube around coated fiber, either a tight 900 µm jacket or a loose gel-filled tube.
Icky pick
Slang for the sticky petroleum gel that fills loose buffer tubes and some cable cores to keep water out.
Fiber color code
The fixed sequence of twelve colors that identifies each fiber and buffer tube in a cable.
Pigtail
A short fiber with a factory connector on one end and bare fiber on the other, spliced onto a cable to terminate it.
Two-fifty
Splicer slang for fiber that has only its 250 µm acrylate coating, with no tight buffer over it.