internal contact resistance

One of the key components in a solar PV installation in Australia is a roof-top DC isolator. While not required in any other country in the world, Australian standards make it mandatory. However no Australian manufacturer makes such a product. So installers in Australia have to buy products from other countries (often these products are not necessarily made specifically for this purpose) and custom modify them to suit the harsh climatic conditions of Australia — no easy feat.

In 2012 iEnergytech tested the internal contact resistance of several brands/models of DC isolators to establish which ones gave the most consistent/reliable results. Measurements were taken in a controlled environment using a Meggar MicroOhmmeter.

The tests revealed that some models were inconsistent while others were not.

The results helped the technical team at iEnergytech determine the best switches to be used in our installations.