Jan 16 2017

Earthing & Bonding

Why on earth does my bonding need checking?

Have you decided to have additional electrical socket outlets, new lighting points, a new circuit installed (such as an electric shower) or any alterations to electrical circuits in your home? If so a NAPIT registered electrician is required, prior to starting work, to verify the earthing and protective bonding arrangements are adequate.

After completion of the electrical installation work no matter how small the job, the work shall be inspected and tested and a certificate issued. Part of this process is to verify that the earthing and bonding conductors are correctly sized, installed and terminated correctly.

Earthing and bonding explained

Earthing is used to protect people from the risk of electric shock. If the earthing arrangements within your electrical installation were defective or inadequate, you could receive an electric shock from the equipment or appliance metal casing.

The purpose of earthing is to provide a path for electric fault current to flow safely to earth to enable the circuit breaker or fuse to operate. Bonding is the connection of the incoming metal gas and water pipes to the main installation earthing terminal and is vital for your protection from electric shock.

In a correctly earthed installation, any appliance or equipment developing a fault to the metal casing, will be quickly disconnected by the operation of the circuit fuse or circuit breaker.


A protective conductor connecting exposed conducting parts of equipment to the main earthing terminal.

Circuit Protective Conductor (CPC)

A protective conductor connecting the main earthing terminal of an installation to an earth electrode or other means of earthing.

Protective Bonding Conductor

Protective conductor provided for protective equipotential bonding.

Residual Current Device a protective

A device which operates when an earth fault is detected.


The conductive mass of the earth, who’s electric potential at any point is conventionally taken as zero.

What do I need to do?

Correctly installed earthing and bonding can protect you from the risk of electrocution and fire caused by faulty equipment or appliances.

An NIC EIC registered electrician can advise you on whether your earthing and bonding installation requires improvements to maintain your safety in the event of an electrical fault occurring. Download more info here.

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