A partial rewire addresses one or more specific sections of a property's electrical installation that have been found to be defective or non-compliant, without replacing the wiring throughout the whole building. This approach is common where an Electrical Installation Condition Report (EICR) has identified deterioration concentrated in a particular area, such as a kitchen, bathroom, extension, or loft conversion.
Partial rewiring is also appropriate when a section of wiring has been damaged—by water ingress, rodent activity, or disruption during building work—or where an addition to the property needs to be brought up to the same standard as a recently upgraded main installation. The electrician will confirm which circuits or sections require replacement and verify that the circuits being retained are in a condition suitable for continued use.
The new wiring must be compatible with the existing consumer unit, or the consumer unit may also need upgrading as part of the scope. As with a full rewire, partial rewiring involves first-fix cable installation—which requires access to wall chases, under floors, or ceiling voids depending on the route—followed by second-fix connection of accessories and testing of all affected circuits.
The scope may be smaller, but the standard of workmanship and the certification requirements are identical. In England, notification is required for a new circuit, a replacement consumer unit, or additions and alterations to existing circuits in defined special locations.
Replacing wiring on an existing circuit is not automatically notifiable; the scope and location matter. All work must meet applicable electrical safety standards, and the electrician should explain the notification and certification arrangements for the proposed work.
On completion, the electrician should provide the appropriate electrical certificate: an Electrical Installation Certificate or, for eligible minor work on an existing circuit, a Minor Electrical Installation Works Certificate. Building Regulations compliance evidence is separate and is required where the work is notifiable.