Earthing System International 

About 

An earthing (or grounding) is system connects specific parts in electrical installations with the Earth's conductor use for safety and functional purposes.  The purpose of this protection to allow fault happening such as leakage current from equipment to go to ground and absorbed by earth. This can minimized damage done on to human or equipment. This is a mandatory requirement in Malaysia and it most important in electrical system as protection.

 1. TT systems

 At one point is connected directly to earth (functional earthing). The exposed-conductive parts of the electrical installation are connected to earth electrodes which are electrically isolated from the earth electrode for earthing the system. 

• T -  Secondary side of supply transformer shall be earthed.  Direct connection of a point with earth. 

• T - All exposed metal frame or body of equipment shall be earth. Earth connection is by a local direct connection to earth. 

Applications of TT system in Malaysia.

• residential supply 

• commercial supply system 

• industry supply system

2.   TN-S system 

This earth terminal is connected by the supply protective conductor (PE) back to the star point (neutral) of the secondary winding of the supply transformer, which is also connected at that point to an earth electrode.   Consumer premise do not have to construct earth chamber and do not required to install an electrode copper rod onto the premise' ground. This safe cost of purchasing complete earthing accessories.

Applications of TN-S system in Malaysia.

• overhead line (LT) supply system  

• NOT ALLOWED  for residential, commercial and industry 

Protective Earth (PE) 

   An earth ground connection of the exposed conductive parts of electrical equipment helps protect from electric shock by keeping the exposed conductive surface of connected devices close to earth potential. 

3.    TN-C-S system 

This method is a basically jointing the neutral and earth together at same  point on the secondary transformer of electricity provider. The protective conductor is being shared same with neutral point, known as protective earth neutral (PEN). 

Terms :   C - combine  but  S - separate 

Applications of TN-C-S system in Malaysia.

• NOT ALLOWED  for residential, commercial and industry 

Protective Earth Neutral (PEN) 

An earth ground connection of the exposed conductive parts of electrical equipment helps protect from electric shock by keeping the exposed conductive surface of connected devices close to earth potential and share together with neutral conductor. 

4.   IT system

This method is where the neutral conductor is not connected to earth. The IT system can have an unearthed supply, or one which is not solidly earthed but is connected to earth through a current limiting impedance. IT system is used for circuits supplying medical equipment  and not allowed for public use.  

• I - indicates either that the supply system is not earthed at all, or that the earthing includes a deliberately-inserted impedance, the purpose of which is to limit fault current.

Applications of IT system in Malaysia.

• NOT ALLOWED   for residential, commercial and industry  

• only for HV transmission line