As we become more aware of occupational health and safety so the need for protection against ground faults is growing. Industrial electrical equipment is fed via a distribution system which in turn is connected to a main feed. Ground fault protection may be installed, for instance at a main breaker, protecting the branch circuit but not necessarily a valuable or critical piece of equipment. Industrial Ground Fault Sensors from NK Technologies are designed to be installed in individual pieces of equipment or their electrical feed. The sensors provide an on/off output that may be used to operate a circuit interruption device like a shunt trip breaker or feed into an alarm system. With over 100 models to choose from, there’s sure to be one to fit your application.
The simple addition of an NK Technologies’ Current Operated Switch in a lighting circuit provides an isolated on/off signal to either a relay to automatically switch to a back-up lamp or signal a PLC to indicate lamp failure. The split-core model is designed for quick and simple installation for existing installations and the solid-core device provides a compact solution for new installations.
This application is similar to the Heat Trace System described previously, however there is a wider choice of generally lower-cost cable, which is often attached directly to roofs and gutters, or imbedded in sidewalks, steps, driveways or car parks. Although this type of installation is sometimes exempt from the code requiring ground fault protection, it is strongly recommended. The simple installation of an NK Technologies’ Ground Fault Sensor will provide an early warning of trouble. Inevitably cable insulation deteriorates with age and stresses such as hydraulic action from ground water, resulting in current leakage to ground. This may create a hazardous situation for people or animals in contact with the installation; it will waste power and cause a significant drop in the heat output and the overall efficiency and thus effectiveness of the system. The circuit may continue to function, but snow and ice could continue to accumulate. If circuit interruption is required NK’s Ground Fault Sensor should be installed in conjunction with a contactor, shunt trip breaker or other approved circuit interruption device.
Industrial electrical heaters are prone to ground leakage due to the breakdown or contamination of insulators. The use of NK Technologies’ Ground Fault Sensors enables early detection of leakage Currents as small as 5mA. The on/off output of the sensor can be used to trigger a circuit interruption device (for example a shunt-trip breaker) or a monitoring device like a PLC to determine the required action. Latching and auto-reset models are available in both normally energized and normally de-energized configurations suitable for most applications.