Transmission Tower Earth Resistance
The concept was extended to measuring the footing resistance of transmission towers. The new method was to fit a very large split core CT around each leg and by measuring the component of test current flowing through each leg in turn, the resulting resistance of each leg could be summated as four parallel resistances.
Complicated but a lot faster, easier and safer than the old practice of climbing the tower, isolating the overhead earth while the ground crew measured the earth resistance by the traditional method.
The technology was just what utilities needed and they purchased hundreds.
Pacific Test Equipment
This and other products from LEM-Norma were the basis for the establishment of Pacific Test Equipment 3-years later in November 1999.
While the original instrument of 1996 is well and truly obsolete and the LEM-Norma company no longer exists, the multi-function earth tester technology has been refined by AEMC and Sonel and continue as industry favourites as the 6471 and MRU-120HD.
The laborious split-core method of tower resistance measurement was updated with the Ground-Flex using four Rogowski Coils to wrap around each leg to measure and summate the tower resistance in a few seconds!
While it was earth testing innovation that kick started Pacific Test Equipment, other new technologies were soon to be added.