Cable route layout

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I am given the task of planning a preliminary cable route layout for a plant. The general plot plan is available. It's a gas treating plant divided into many units.
The problem is that I have no idea of how to do it. Well, I'm not that experienced and my work is going to be checked and revised for sure. Still, I'd like to do a better job rather than drawing random lines in a cad drawing and hatching them to show trenches!

To begin with, can anyone help me with the following questions?

1) What are the main concerns while designing cable route layout?

2) Does elevation changes affects the construction of trench too much? Should the path of trenches go around slopes or not?

3) The drawing is supposed to be preliminary. Is the width of trenches important in this stage? We have just an estimate of the loads in plant.


Any comments/links would be highly appreiciated.
 
All too often, those monks with their sandals in the ivory towers just think in terms of cost per foot and what is easiest to draw on their CAD screens -- a straight line. You bring up a good point about slopes.
Actually PVC conduit is usually used for underground since, if something goes wrong, you can hopefully pulll out the broken cable and pull in new wires. Or you can even pull in larger cable so go to the next larger size.
Slope is a consideration when you are using a tractor DitchWitch. Stability and safety against tipping should be a practical concern. Perhaps a 20% slope straight up and 10% crossways but it is up to the operator in the field as to what is comfortable. In other words, do not take my numbers as gospel.
The width of the trench should be at least the outside diameter of the pipe.
As always, consider the type of soil/rock. Call that new dig alert number beforehand. Also avoid cutting with-in the root zone of vulnerable trees.
~Peter
 
I do lots of layout from construction drawings to shop drawings for actual layout. Maybe a little more info on your drawings would help me answer your question.

What are you laying out? Specifically are you laying out, an underground duct bank or smaller feeders?

Why are you laying it out? Are you working on a set of plans for a contractor like shop drawings or are you working with an engineering firm to develop construction drawings? What is the intent of the drawings? (it makes a difference in how I answer your question)
 
the variables here are too numerous to mantion. u/g work is so vague. cover your as-. no one is giong to pay you for your extra work that is not specified in the contract. cya!!!!!!
 
ITO said:
I do lots of layout from construction drawings to shop drawings for actual layout. Maybe a little more info on your drawings would help me answer your question.

What are you laying out? Specifically are you laying out, an underground duct bank or smaller feeders?

Why are you laying it out? Are you working on a set of plans for a contractor like shop drawings or are you working with an engineering firm to develop construction drawings? What is the intent of the drawings? (it makes a difference in how I answer your question)
Click to expand...

Thanks for paying attention.

1) They're going to run 33KV, 6KV, and LV cables through trenches. And some trenches should contain cables with different voltage ratings. The trench walls will be probably built out of concrete and their depth-again probably-won't be more than 6ft.

2) I'm working with electrical department of an engineering firm. The firm is only responsible for engineering of the plant. Procurement and construction is out of their scope of work.
 
Ok sorry, I don't do much medium voltage work and probably should not be giving advice on it.

For the work I do, the engineer typically just does a generic layout avoiding building lines, and completely ignores any topographical concerns. Its up to the EC (like me) to actually figure out a path and make it work.
 
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