For j thompson who wants more info on me drilling roof trusses?

Question:yes i'm talking about 2 x 4 trusses, i wish to run a cable through my loft at high level (loft is floored), size of hole to be drilled is 10 - 16mm

Answers:
Small hole should be no problem. Be very careful though. These are "engineered" components that may not be modified. Damage one and the load goes to the adjacent ones and they are not designed to handle the job. Different parts of the truss are in compression and others are in tension. Complicated system.
Given that.drill small holes only. Stay in middle of the width of the lumber and stay out of the middle of any span. DO NOT break an edge of the framing member EVER on a truss, such as "notching".