Is there any guidance or recommendations for where cables are installed within the ground for a small length of their run and appropriate grouping factors that can be applied?
I have an existing site with single core cables installed from a transformer to a main panel 14m away. 2m is within the ground, whilst the rest is on ladder on the out side of the building and out of the ground directly into the transformer.
The only way I can get the calculations to pass is to put them through the software as been on ladder through out their entire run which as I mentioned above, is not the case. Even when using and the ERA values for in the ground, I still cant get it to pass.
I appreciate that when installed in the ground, the issue is its harder to dissipate the heat so I would normally use this as worse case and use the ratings for buried in the ground in my calculations or as mentioned, is there any other guidance on this which the previous designers/installers have factored in that I am missing?
Thank you in advance.