Final answer:
The question is related to determining the dimensions of a pull box in electrical engineering, ensuring clearance for locknut and adherence to guidelines for space required for cable pulling.
Step-by-step explanation:
The question pertains to determining the dimensions for a pull box in an electrical engineering context, where there needs to be a specific clearance between the sides of conduits and the sides of the box. The clearance is specified as 25.4 mm for locknut. The "rule of thumb" mentioned in the question refers to the size of the pull box relative to the conduits running into it. While older guidelines suggest 5 diameters side-to-side and 7-8 diameters deep, newer guidelines recommend as much as 8 diameters side-to-side and 15 diameters deep for the pull box dimensions. This information assists in ensuring that there is sufficient space within the pull box for ease of pulling cables, as well as meeting safety and building code requirements.