Standard explained
BS 7671 Inspection and Testing Explained
BS 7671 sets out initial verification of new work and periodic inspection of existing installations, including the dead and live tests that confirm an installation is safe.
Part of BS 7671 is devoted to inspection and testing — the procedures that confirm an installation is safe, both when newly installed and periodically throughout its life.
Two contexts
- Initial verification — carried out on new installations and major alterations before they are put into service, resulting in an Electrical Installation Certificate (EIC).
- Periodic inspection — carried out at intervals on existing installations, resulting in an Electrical Installation Condition Report (EICR).
The core tests
Whether initial or periodic, testing follows a logical sequence of dead tests (with the supply isolated) and live tests (with the supply on):
- Dead: continuity of conductors, insulation resistance, polarity.
- Live: earth fault loop impedance, RCD operation, prospective fault current.
Why the sequence matters
The order is a safety measure — dead tests confirm the installation is safe to energise before live tests begin. Following the model forms and procedures ensures results are consistent, comparable and defensible. For what this looks like on a real EICR, see what happens during an EICR.
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