I am installing fiber optic cables between two buildings. Is there a specific # of pull boxes in a underground PVC conduit run? I was told Every 100' there should be a box. I have a copy of the 1996 NEC handbook and could not find anything.

Thank you,

Shonn Diess

Looking in my 1999/2002 nec now for relevant (if any) code articles.

Some basic questions:

Have you ever pulled fiber optic cables before ? Have you been trained on how to correctly pull fiber cables ? Fiber cables are easily damaged if not pulled properly.

How long is the run going to end up being ?

Do you require service loops at these 100' intervals ?

The guy pulling the fiber (you) would probably appreciate the JB's every now and then.

Shonn:

You should invest in a new copy of the 2002 NECH, I found many rules that apply to the questions you asked, and there are lots of Article 300 rules thay can be applied.

With fiber, you want to reduce the number of times that you have to handle it. Every time you pull it out of a box and loop it to refeed it in, you run additional risk of damage from kinking or other problems. Do a pulling force calculation and make sure that the pulling force required for your pull is less than what is permitted by the manufacturer. As long as the pulling force is within the specs, only place pull points where they are needed for the fiber terminataions. Whenever you use any type of pulling point you have to look at the minimum bending radius permitted for the fiber. In many cases this will require a pull box and not a conduit body.
Don(resqcapt19)