MEPworx Wiring – Temperature Derate function for Final Boards and Ways

By David Wren

You can already add Temperature Derating data (Derate) to breakers in the CPD Database program.

This was primarily introduced for use with gPV Fuses in PV Array systems, where the installations are designed to operate at higher ambient temperatures.

Where Temperature Derate data has been added to the default CPD Type being used in your Final Board, you can now make use of a higher Enclosure Temperature. As illustrated below, this is selected from the Enclosure Temperature pull-down in the General Details for Final Boards.

This new function is available to Single Section boards, also the Parent or Sub Sections of Split Section boards.

When an Enclosure Temperature has been selected from the pull-down list, the resultant reduced CPD rating will be applied to all the CPDs on the outgoing Ways of the board, or it’s sub sections.

Where required, the Enclosure Temperature can be further edited for the Ways individually, on a circuit-by-circuit basis.

To assist with exploring this feature, Temperature Derate data has been added to Generic CPD entries for Fuses, AFDDs, MCBs & RCBOs as below:

• Fuses, BS-88, BS88-3, BS-1361. (gPV fuses already have entered Derate data)
• AFDD/RCBO - Type B, C & D with Type A RCD trip
• AFDD/MCB - Type B, C & D
• MCB - Type B, C & D
• RCBO - Type B, C & D with Type A RCD trip

These breakers are available in the 18th Edition CPD DB and the latest versions of each of the manufacturers CPD DBs.

Please refer to the Wiring Program's Help (F1) for more information.