For panel builders, understanding how to distribute electrical power is important. Get that right and everything works as expected. But, if current, frequency, or operating temperature is not properly accounted for, then busbars and components can overheat. Field failures are expensive in terms of money, reputation, and the prospects for future projects.
For power distribution systems designed for any voltage, be sure to:
- Adhere to the recommendations of IEC 61439 or the appropriate local standard.
- Follow the installation guidelines and recommendations provided by all the original manufacturers when it comes to derating, assembly and more. This may mean that several manufacturers’ instructions must be accounted for. If using a unique manufacturer’s pre-fabricated solution, this is already taken care of.
- Use the right type of copper or aluminum.
Regarding the first point, IEC 61439 provides rules needed to ensure the quality and safety of the switchboard as well as how to test it. For instance, it specifies how big a conductor must be to safely handle a given amount of current under stated operating and environmental conditions.
However, as the second item above notes, manufacturers often provide additional information about how to assemble devices in a switchboard and how to derate them for environmental and operational circumstances. If manufacturer instructions are available, follow them. At times products and solutions from several manufacturers are involved, and so all the recommendations – which could conflict – should be adhered to. Alternatively, if using a pre-fabricated solution, then following guidelines and recommendations is already taken care of.
Finally, the third point is important because the quality of the conductor determines overall system quality.
Copper should be Cu-ETP H12 or the equivalent. It has the required conductivity, which means that busbars will not get too hot. It also has the needed malleability and mechanical properties, which means that it can be bent, drilled and cut without a problem. For similar reasons, aluminum should be a grade with between 55 and 61 percent conductivity as defined by the International Annealed Copper Standard. Thus, it should be grade 1350 or 6101, as specified by the ASTM B609 or ASTM B317 standard, respectively. It also must have the right surface treatment and not be raw aluminum so that conductivity is retained for a long time.