Earthing and Bonding
What is Earthing and Bonding ?
Earthing and bonding are two different types of fault protection.
Earthing is where the exposed conductive parts of the installation are connected to the main earthing terminal situated normally at the mains supply.
Bonding is where exposed conductive parts are connected to prevent hazardous voltages to touch, such as hot and cold water pipes.
Why do I need Earthing and Bonding ?
The connection to earth is a safe route for the fault current to flow significantly reducing the risk of electric shock
What can happen if my Earthing and Bonding connection is missing or broken?
There is a highly increased risk of conductive parts of appliances becoming live and causing electric shock.
Circuit breakers will fail to trip when there is a fault.
How can I tell if my Earthing and Bonding is compliant ?
An EICR condition report would identify any earthing defects in an installation.
What are the Earthing and bonding checks done during an EICR
When carrying out an EICR inspection the electrician will be checking the following items
The Presence and condition of the distributors earthing arrangement
Visual checks will be made of the main incoming supply to check the provision of a main earth.
The main earth will be disconnected from the bonding and an external earth loop impedence test will be performed.
The Presence and condition of the earth electrode
If a TT system or there is a requirement for additional earth electrodes then these will be inspected and earth electrode resistance tests will be carried out
The Provision of earthing and bonding labels at appropriate locations
It is required that safety electrical connections are all appropriately labelled at their location
Confirmation of earthing conductor sizes
Earthing conductor sizes are required to be checked for adequacy as set out in BS7671
Accessibility and condition of earthing conductor at the main earthing terminal
The condition of the main earthing connection will be assessed
Confirmation of the main bonding conductor sizes
The size of the main protective bonding conductors will be checked
The condition and adequacy of the main bonding conductor connections
The condition of the main bonding connections will be checked
Accessibility and condition of other protective bonding connections
Other protective bonding connections will be checked.
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