Electrical testing intervals: what actually determines them

"How often do we need an EICR" is one of the most common questions a facilities team asks, and the honest answer is that there isn't one fixed number that applies universally. The interval is meant to be set by the inspecting engineer based on the type of installation, how it's used, and its condition — not read off a single table that applies the same way to every building.

Why the interval isn't fixed

Guidance from bodies like the IET and NICEIC gives typical maximum intervals for different premises types, but these are starting reference points, not guarantees. An installation in heavy, harsh, or industrial use may reasonably need testing more often than the typical guidance suggests; a lightly used, well-maintained installation in a benign environment might reasonably sit at the longer end. The engineer doing the inspection is meant to set the next interval based on what they actually find, not simply reapply the previous one by default.

What actually happens during the inspection

An Electrical Installation Condition Report inspects the fixed wiring and electrical installation of a building — not portable appliances, which sit under separate PAT testing — and classifies any issues found by severity, from observations worth noting through to defects that need urgent attention. The report itself is the evidence; the interval to the next one is a recommendation within it, specific to that building.

• –Type of premises and how the installation is actually used, not just its category on paper
• –Age and condition of the existing wiring and distribution equipment
• –Environmental factors — moisture, temperature, dust, or heavy mechanical use
• –Findings from the previous inspection, including any pattern of recurring faults

Acting on the classifications, not just filing the report

A report that comes back with defects classified as needing attention is only useful if those findings actually turn into tracked work. This is the same pattern that shows up across every statutory inspection category — the inspection itself is rarely where things go wrong, it's the gap between a finding on paper and a completed remedial job that leaves a facilities team exposed months later when someone asks for evidence.

Keeping installation records tied to the asset register — which distribution boards exist, where, and what their inspection history looks like — makes it much easier to demonstrate a coherent picture across a whole estate, rather than a folder of disconnected certificates that each need to be individually located when someone asks.

Always confirm the appropriate interval and classification scheme with a qualified electrical inspector working to current IET and BS 7671 guidance — this post describes the shape of the process, not a substitute for that professional judgement.