Copper takes the strain

To help reduce commercial electricity bills the Copper Development Association (CDA) has issued an interactive software package that takes the strain out of calculating optimum power cable and busbar sizes for maximum cost savings and optimum payback periods.

The package consists of two programmes, Energy Efficient Power Cable Selection and Energy Efficient Busbar Design, both of which can demonstrate payback periods of less than one year for up-sized energy efficient conductors. Energy is lost in all current carrying cables and busbars in the form of heat due to electrical resistance, so called l2R losses.

Using the minimum regulation size means hotter running and greater losses. Larger sizes save energy and reduce running costs over the lifetime of the installation. The energy saved is worth many times the slightly increased cost of larger cables and busbars and can give very short payback periods.

The Energy Efficient Power Cable Selection program calculates cable size taking account of type of cable, installation method, circuit length, overload protection, ambient temperature and circuit grouping. Results are presented for the minimum size (that is, BS 7671) and for each incremental size up to the most economic size (that is, IEC 1059). For each size, the overall lifetime cost and the payback period are calculated. The economic calculations take account of load growth, discount rate and increases in energy costs. Cable and installation costs can be modified by the user to suit local conditions.

The two programs can be obtained from CDA on the new CD-ROM Megabytes on Coppers 11 or on two floppy disks at a cost of £20, for PC format only.