Housing of an electrical equipment is earthed by directly connecting it to a earth grid or earth electrode, which provides a low resistance path to ground. In case of a fault involving earth the live part of the equipment gets connected with the low resistance earth path. This produces high earth fault current and the protective devices in the circuit disconnects the circuit from the power source thereby reducing further damage to the equipment. This is how an earthing protection system works.
But many a times it so happen that earthing equipment installed around the commercial building gets stolen. Though it is recommended to check the earthing resistance every six months in order to assess the health of earthing system but sometimes thefts take place even after few days of getting the earthing protection system installed. Today there are very good tools which renders help is assessing the health of your electrical system.
For 220 kV systems AC line fault detector manufactured by many SMEs in the country can help you find out the real problems in your AC line. One of the manufacturer offers following signals for fault detection.
- ALL OK
- EARTHING FAULTY
- NEUTRAL FAULTY
- LIVE & NEUTRAL REVERSED
- LIVE FAULTY
To ensure you have a healthy Earthing protection system, get hold of one such instrument. Below is a useful video courtsey EATechPodCast.