The RLTXERTH is a valuable addition to Ringline signal line. It is designed to continuously monitor earth leakage of the Ringline field bus. Although Ringline is rubust enough to tolerate a single earth on the system, multiple earths and partial shorts on the two wire, will cause the system to shut down due to false data transmissions. With The RLTXERTH Partial earths may be monitored and logged then identified and cleared later during schedulled maintenance before the problem causes a shutdown. This transmitter replaces the need to manually check for earths with a meter as part of a regular maintenance program. The transmitter is fully powered from the Ringline field bus and at the same time encodes the status of earth leakage back onto the bus allowing easy installation.