Hi,
I do a lot of cable calculations for Electric vehicle chargers and it is often that our client wants to run the cabling as 5 core, with the 5th core as the earth.
My question is, what is the correct way to do this. I have always used XLPE/SWA 4 core and then selected the CPC to be 'Live Core', which then takes (i believe) the 5th core to be the same size as the cable is fixed at.
However, a senior electrical engineer at the company selects 'armour & auxillary' and then fixes the CPC size to be the same as the fixed cable size.
Please can someone let me know which method is correct and how much of a difference the two methods will have on the CPC size, if any.
Thanks, Luke
Hi Luke,
I would personally suggest that it may not be a case of which is correct / incorrect, but which closer approximates the design you wish to achieve - in general I would always advise choosing the most conservative option to ensure a factor of safety. Not sure if suits your needs, but another approach may be to add your own specific cable for this situation via 18th Edition > Cable Data > Add new cable file (eg as below), as then you will have full control over its data?
Regards,
Shane
Shane Regan | Principle Building Performance Support EngineerHevacomp to OpenBuildings - A complete guide for every user | Bentley Communities
Hi Shane,
Okay.
Am i correct in thinking that if i select a 4 core cable and then select live core, that hevacomp takes this as the 5th core, at the same size as the cable size is fixed at? If that is correct then i will continue to use this method. If not, then please can you suggest the correct CPC to select?
Luke