joist span confusion

[bureaucrazy]

I must run fp cable under floor perpendicular to Joists. i must drill holes in Joists and thread cable through. safe zone is 0.25 to 0.4 of span length. the Joists run as a continuous piece of wood from front wall to rear wall but are supported halfway by a wall underneath. should i therefore consider there to be a single long span giving two large drilling zones or instead two shorter spans measured from the intermediate supporting wall giving four smaller drill zones?

 

[Spudnik]

The span is taken from where the joists are supported, so its from one end to the central support wall.

 

[Guest123]

As Jason said mate.
Just bear in mind holes should be on "X" axis and no closer than 3 times the size of the hole you are drilling.