What does an EICR check? The tests explained

An EICR checks whether the fixed electrical installation in a property — the consumer unit, wiring, sockets, switches, light fittings and wired-in equipment — is safe to keep using. It has two parts: a visual inspection, then a series of electrical tests on the circuits. Together they look for the four things the government’s guidance for landlords lists: circuits that are overloaded, electric shock risks and fire hazards, defective electrical work, and missing earthing or bonding.

Here is what happens at each stage, and what each test proves.

Part 1: the visual inspection

First, the electrician looks over the installation, working through a standard checklist called the schedule of inspections. They check:

• The intake — the meter tails and main switch. The supplier’s cut-out and meter aren’t opened, but if something there looks dangerous, you should be told in writing so you can report it.
• Earthing and bonding — that the main earthing conductor is present, the right size and securely connected, and that the incoming gas and water pipes are bonded to it.
• The consumer unit — how it’s fixed, whether the enclosure is damaged, whether the circuits are labelled, and whether there’s a notice reminding you to test your RCDs.
• Wiring and accessories — damaged cables, cracked or scorched sockets and switches, loose fittings, signs of overheating, and cables run where they could be damaged.
• Bathrooms and shower rooms — RCD protection, bonding where it’s needed, and sockets kept a safe distance from the bath or shower.
• Additions and alterations — signs of later work, which the report asks the inspector to note.

An installation built to an older edition of the wiring regulations isn’t automatically unsafe — the standard report form says so. The inspector’s job is to judge whether it is safe now.

Part 2: the tests, and what each one proves

Testing is done circuit by circuit. Some tests need the power off and others need it on, which is why the power goes off in short bursts during the visit — see how long an EICR takes.

Continuity of protective conductors

What it checks: that the earth conductor runs unbroken from the consumer unit to every socket, light and fitting on the circuit, and that the bonding to the gas and water pipes is connected.

Why it matters: if a fault makes a metal part live, the earth conductor carries the fault current away so the fuse or circuit-breaker can switch off. A broken earth means that metal part could stay live.

Ring circuit continuity

Many homes have socket circuits wired as a ring: the cable leaves the consumer unit, loops round the sockets and comes back. The electrician measures each conductor of the ring from end to end.

Why it matters: a break in the ring can go unnoticed because the sockets still work — but part of the cable may then carry more current than it was designed for.

Insulation resistance

What it checks: that the insulation around the conductors is sound. A test voltage is applied between the conductors, and between each conductor and earth, and the resistance is measured in megohms (MΩ).

Why it matters: insulation that has broken down — through age, heat, damp or a nail through a cable — can leak current, which is a shock and fire risk. For ordinary 230-volt circuits, a reading below 1 megohm doesn’t meet BS 7671 and should be given a code.

Electronic equipment can be damaged by the test voltage, so it’s unplugged or disconnected first — which is why you may be asked to unplug computers and chargers.

Polarity

What it checks: that every switch, fuse and circuit-breaker is in the line (live) conductor rather than the neutral, and that sockets and light fittings are connected the right way round.

Why it matters: with the polarity reversed, a light can be switched off while the fitting is still live — a real risk for anyone changing a bulb. Industry guidance codes incorrect polarity at a socket or fitting as potentially dangerous (C2).

Earth fault loop impedance

What it checks: the resistance of the path a fault current would take — out along the line conductor, back through the earth and round through the supply. It’s measured at the incoming supply (known as Ze) and at the far end of each circuit (Zs).

Why it matters: the lower the impedance, the more current flows in a fault and the faster the fuse or circuit-breaker switches off. Each reading is compared with the maximum BS 7671 allows for that protective device. A reading that’s too high, on a circuit with no RCD, means a fault might not be cleared quickly enough — usually a C2.

The electrician also measures the prospective fault current — the most current that could flow in a short circuit — and checks the fuses and circuit-breakers are able to break it safely.

RCD tests

What it checks: that each RCD — the safety switch that cuts the power when current leaks to earth — switches off quickly enough. The test instrument simulates a leak at the RCD’s rated current (usually 30 mA in a home) and records the time it takes to trip, in milliseconds. A standard RCD must switch off within 300 milliseconds. The electrician also checks the test button works, and operates the main switch, circuit-breakers and RCDs by hand to prove they switch off.

Why it matters: an RCD reduces the risk of injury from a common type of electric shock. A main RCD that doesn’t trip when tested is coded C2. There’s more in RCDs explained: why your EICR mentions them.

The tests at a glance

What an EICR doesn’t cover

Every EICR has limits, and a good report says what they were.

• Hidden cables. Unless agreed beforehand, cables under floors, in roof spaces and inside walls aren’t inspected, although the tests still show up many hidden faults.
• Parts that couldn’t be reached — a locked room, say — are recorded as limitations, with the reason.
• Product recalls. Equipment isn’t checked against safety alerts or recall lists.
• Plug-in appliances. Kettles, lamps and extension leads are covered by PAT testing, not the EICR.
• Fault-finding. An EICR assesses condition; it isn’t a repair visit. If a result points to a problem the electrician can’t pin down, it’s recorded as FI — further investigation.

How the results are recorded

Everything goes into the report: the schedule of inspections, a schedule of circuit details, and a schedule of test results with the readings for each circuit. The report form says it is only valid when those schedules are attached — so if you’re handed a single summary page, ask for the rest.

Each problem gets a code: C1 (danger present), C2 (potentially dangerous), C3 (improvement recommended) or FI (further investigation). Any C1 or C2 makes the report unsatisfactory. See EICR codes explained, or see an example on our sample report page.

Key points

• An EICR is a visual inspection plus a set of tests on the circuits.
• The tests check that earth paths are unbroken, insulation is sound, polarity is right, faults will be cleared quickly and RCDs trip in time.
• Every reading is compared with the limits in BS 7671, the UK wiring regulations.
• Hidden cables, product recalls and plug-in appliances are outside a standard EICR.
• A complete report includes the schedules of inspections and test results.

Book an EICR that tests every circuit

We test every circuit to BS 7671, email you the full report as a PDF and explain every code in plain English. If anything needs fixing, you get a clear quote, with no obligation to use us. Prices start at £90 inc VAT (£75 + VAT) for a studio to two-bedroom flat with one consumer unit, and you see your price before you book.

Get your price, read about our landlord EICR and homeowner EICR services, or call 07301 010244.