By David Wren
A question that is sometimes asked is, “How can I check the temperature of a cable, working under its design conditions?”. This is quite straightforward and can be easily viewed in Wiring’s Schedules. These can be selected from the Display ribbon in both the Sub Mains and Final Circuit modes.In the example of a board’s Final Circuit Schedule shown below, the information relating to the cable’s temperature is in the 3rd column from the right. Here, the last two sets of figures show the Operational Temperature of the cable under its design conditions and the cable’s Design Temperature Rating.
Taking the data for the TP&N Way 3, the cable type used here is LSF which is a 90°C rated cable. Under its design conditions it can be seen that the Operational Temperature is only 73.2°C, which is well within the performance specification for this cable type, but is also greater than the maximum temperature rating of the 70°C PVC cables also in this final board.
By reviewing the cable data here in the Schedules, you can easily see that you need to increase the size of the LSF cables on Way 3, so as to reduce its operational temperature to be less than the 70°C rating of the PVC cables.