Was talking to a switchboard manufacturer and he mentioned that the switchboards manufactured to BS 61439 are only tested to 70 degrees C, so all the cables attached to/from it must be calculated for 70 degrees. The only reference in the standard which makes some sense about this is section 10.2.3.1 attached. This means that all the XLPE cabling out there which is rated at 90 degrees is under-utilised and is useless.
Many designers I assume, are not aware and proceed in producing the calculations in Amtech or similar with cables to set operate at 90 degrees and think all is ok.
I did some googling on their website and found the below. Two of their specification engineers also agree that they quote the switchboards to be only permitted to accept 70 degree cables. As far as the standard they are manufactured to, is not very clear about this 70 degree property. Could not find any reference to that apart from that section talking about testing.
I did some googling on their website and found the below. Two of their specification engineers also agree that they quote the switchboards to be only permitted to accept 70 degree cables. As far as the standard they are manufactured to, is not very clear about this 70 degree property. Could not find any reference to that apart from that section talking about testing.
