MAINTENANCE-FREE EARTH & RING EARTH
his type of earthing and bonding system is
adopted for S&T equipments with solid state
components which are more susceptible to
damage due to surges, transients and overvoltages being encountered in the system due to
lightning, sub-station switching etc. these
equipments include Electronic Interlocking,
Integrated Power Supply equipment, Digital Axle
Counter, Data Logger etc.
This type of earthing arrangement requires no
maintenance so called as “Maintenance free
earthing or “Effective Earthing”. Effective earthing
electrode eliminates problems of conventional
1. By providing highly corrosion resistant
2. By eliminating the corrosion causing elements
in the salt.
3. By providing uniform non corrosive, low soil
resistivity material around the electrode.
1.1 Importance of Earthing
1. Efficiently dissipate electric surge to protect
equipments thus minimize downtime, service
interruption & replacement cost.
2. Provide a stable reference for electrical and RF
circuits to minimize noise during normal
3. Protect staff from dangerous electric shock.
1.2 Characteristics of good Earthing System
1. Low resistance and electrical impedance
2. Conductors of sufficient dimensions capable of
withstanding high fault current.
3. Lower earth resistance ensures that energy is
dissipated into the ground in the safest possible
1.3 Location for earth
1. Low lying areas close to building or equipment
2. Close to existing water points but not naturally
3. Avoid Dry sand, lime stone, granite, stony ground
and high bank.