Pull boxes shall be sized so that no cables in the box shall be tightly bent.
Fiber pull box distance.
The cables minimum bending radii shall not be violated.
Doing so can result in bending losses and or fiber breaks in the cable.
Calculating the correct size of pull box needed can be complicated so please feel free to contact us or call 800 767 1576 if you need assistance.
Always install listed optical fiber raceways per the following ent rules.
Determining the size of underground pull and junction boxes to meet nec 314 16 code standards is required to prevent damage to conductor insulation.
Figure 4 figure 5.
In many runs if the pulling distance is short enough and the pathway straight enough fiber optic cable can be pulled by hand without the use of special equipment.
Never exceed the maximum pulling load rating.
Inspect the cable run to ensure there are no sharp bends or corners that exceed the minimum bend radius of the fiber.
Typically optical fiber cables do not carry electrical power but the metallic components of a conductive cable.
You should pull on the fiber cable strength members only.
On long runs use proper lubricants and make sure they are compatible with the cable jacket.
On really long runs pull from the middle out to both ends.
Generally the minimum bending radius of a fiber cable under load is 20 d where d is the diameter of cable.
Installing a pull box after the second 90 degree bend or equivalent amount of degrees of bend in a conduit run is recommended.
The cable should never be bent below its minimum bending radius.
Fiber optic cables have kevlar aramid yarn or a fiberglass rod as their strength member.
2 in many runs if the pulling distance is short enough and the pathway straight enough fiber optic cable can be pulled by hand without the use of special equipment.
At river crossings the distance between the bottom of the water and the drilling hole should be 10 times the diameter of the pipe and not less than 3 m 10 feet.
Ansi tia 569 b 2004 commercial building standard for telecommunications pathways and spaces section 8 8 2 3 offers some guidance regarding cable fill in conduit.
362 24 bending radius 362 26 maximum total bends between pull points 360 362 28 trimmed to remove rough edges 362 30 support every 3 ft within 3 ft of any enclosure 362 48 joints between tubing fittings and boxes what about raceway fill.
Loops of cable commonly called service loops shall be provided at all intermediate pulling points such as in manholes and pull boxes.
How to calculate underground pull box sizing.
Procedures for pulling fiber optic cable.
A length of free cable shall be provided at each end of a cable pull.
Optical fiber cables are designed with a minimum bending radius.
