The wiring regulations BS7671:2008 explain that all new wiring must be correctly Designed, installed and Tested to comply with current regulations. In the first instance testing allows the electrician to confirm the new wiring meets the regulations.
Secondandly we test to understand how the wiring in a particular installation has coped over time. Wiring will deteriorate with age and this could be due to environmental factors such as damp, heat and cold, or it could be due to damage for example rodent damage, or even through modifications made by homeowners. Testing in this situation allows the electrician to understand the condition of the wiring.
Because so much of the wiring in a house is covered, testing is the only way to understand the condition of the wiring in a house.
To show compliance with the regulation all testing results are recorded on 2 main types of certificates.
Electrical Installation Certificates - Used for 1 or more new circuits, re-wires or new builds
Minor Works Certificates - Used for any modification work on a single circuit where any new additional wiring has been fitted.
Inspection works hand in hand with testing. As much as possible electricians will use all their senses to inspect the condition of the wiring that is visible.
Looking at the condition of the wiring for signs of heat damage or rodent damage are the most the most obvious place to start, but smell is also import as well as touch, a wire may look ok, but if it feels hard and brittle then that may be a sign of overheating.
For examples of the type of problems encountered in a typical house look at the Rogues Galley on this website
All work covered under the banner of Part P needs to have an electrical certificate. These basically prove to whom ever purchases your house in the future that the electrical works undertaken has been tested and meets the regulations.
There are 3 major types of certificates...
Minor works certificate
Electrical Installation certificate
Electrical Inspection and Condition Report
A Minor Works Certificate
The minor works certificate is only to be used for additions to an electrical installation that do not extend to the introduction of a new circuit e.g. the addition of a socket-outlet or a lighting point, to an existing circuit.
Electrical Installation & Certification
The Electrical Installation Certificate is to be used only for the initial certification of a new installation or for an alteration or addition to an existing installation where new circuits have been introduced.
Typically used for new builds, re-wires, anywhere a new circuit has been installed.
Electrical Inspection and Condition Report (EICR)
When people require their electrics to be checked, they often call it different things:
An electrical safety check
An electrical survey
I need my electrics checked
Can you inspect my electrics?
Are my electrics safe
Have I got dodgy electrics?
Can you look at my electrics?
An electrical safety report
An electrical safety certificate
A Landlords electrical safety certificate - More on this later
NICEIC electrical certificate.
What they are asking for in all these cases is an in-service, inspection and more importantly, a test of their electrical installation. This is known as only one thing in the IEE wiring regulations - an Electrical Inspection and Condition Report (EICR).
An EICR is ideal to assess the condition of an installation prior to selling, buying or renting a property... or just for peace of mind. However, the IEE Wiring Regulations recommend that an EICR should be considered for the following reasons:
A change of occupancy of the premises
A change of use of the premises
After alterations or additions to the original installation
Because of significant change in the electrical loading of the installation
Where there is reason to believe that damage may have been caused to the installation.