In Trimble, Pro Design UK, for carrying out the cable calculations for Street lighting do we have to really use GROUPING option in the calculations? How does this help in the calcs for a single phase or a 3phase supply ?
Is your cable grouped with any other cables running at more than 1/3 of their grouped ratings? If so you enter the number in the box. If you have grouped cables either single or 3 phase it does not help but will derate your cable so you may need are larger CSA.
Yes , i have more than 3 cable running in a duct all of them 10sqmm. Do we have to really specify grouping for cables running together in ducts as we do a worst case design?
Yes if they are running in ducts together. You also have to look at depth of lay and the thermal resistive the of the soil. Are your 10mm cables fully loaded?
Punch all the data in to your Trimble and hit the calculate button and see what the outcome is. Then go in to reports and then cable analysis and see what the running temperature is?
