Guide · Electrical Safety
RCDs explained: the device your EICR keeps mentioning
No component appears in landlord EICR conversations as often, or as opaquely, as the RCD. Inspectors code its absence, electricians quote for adding it, and consumer-unit upgrades revolve around it — while many landlords couldn't say what it actually does. Here is the device explained, and why the wiring standards keep raising its status.
Electrical Safety
What does an RCD actually do?
It watches for missing current: electricity flowing into a circuit should flow back in equal measure, and an imbalance means current is leaking somewhere it shouldn't — through damaged insulation, through water, or through a person. A residual current device detects that imbalance and disconnects in a fraction of a second, fast enough to matter to a human heart.
That makes it a different creature from a fuse or circuit breaker, which respond to overloads and short circuits — faults measured in tens of amps. The RCD responds to leakages measured in thousandths of an amp: exactly the scale of a shock through a body, which is why it is described, without exaggeration, as life-protection.
Electrical Safety
Where do the wiring standards expect RCD protection?
Modern editions of the wiring regulations expect RCD protection across progressively more of the domestic installation — socket circuits, bathroom locations, cables buried in walls, and in current practice effectively the whole consumer unit's outgoing ways. Each edition has widened the net, reflecting decades of evidence about where shocks and fires actually start.
Older installations were wired to older editions, and that is not automatically a breach: the standards are not retrospective. What it does mean is that an installation without RCD protection is measurably behind current safety practice — and the EICR is the mechanism through which that gap gets formally observed and judged.
Electrical Safety
What does missing RCD protection mean on an EICR?
A coded observation, with the code depending on context: the inspector weighs which circuits are unprotected, what they serve, and the installation's overall condition. Absence of RCD protection in higher-risk locations tends to attract the codes that make a report unsatisfactory; in other contexts it may be recorded as an improvement recommendation.
The coding is the inspector's professional judgement on the day, not a lookup table — which is why two reports on similar properties can differ. What a landlord should take from any RCD observation is direction of travel: the device is cheap relative to what it protects, and every standards revision has moved toward more of it.
Electrical Safety
How do RCDs reach an existing installation?
Several routes, scaled to budget: a full consumer-unit replacement bringing every circuit under RCD protection is the comprehensive fix and the usual companion to other remedial work; individual RCBOs (breaker and RCD combined per circuit) offer finer-grained protection; and socket-level RCDs exist as a narrow, partial measure for specific points.
The consumer-unit route has become the default in rental stock because it resets the whole board to current standards in one certificated job: modern protective devices, proper labelling, and an Electrical Installation Certificate that gives the next EICR a clean baseline. It is the upgrade that retires a whole family of observations at once.
Electrical Safety
Why do RCDs trip, and when is tripping a fault?
A trip is the device doing its job — the question is what it caught. One-off trips after storms or with a particular appliance plugged in usually indicate a genuine leakage from moisture or a failing appliance; the appliance-by-elimination test (unplug everything, reintroduce one at a time) identifies the culprit in most household cases.
Repeated tripping with no appliance cause is installation territory: deteriorating insulation, moisture ingress into fittings, or a fault developing on a circuit — and it belongs with an electrician, not with the temptation to hold the switch on. An RCD that keeps tripping is reporting a problem; silencing the reporter is not a repair.
Electrical Safety
What testing do RCDs need between EICRs?
Two kinds: the built-in test button, which anyone can press and which mechanically exercises the device — worth doing on a routine such as tenancy changeover, with the date logged — and the instrument test an electrician performs, measuring actual disconnection times, which the EICR includes as standard.
The test button deserves a line in the tenant welcome pack: what the switches are, that a trip usually means an appliance fault, and how to reset safely. A tenant who understands the board reports intelligently; one who doesn't lives with a tripping circuit or, worse, improvises around it.
Electrical Safety
How should a landlord think about the upgrade decision?
As sequencing rather than whether: an installation without modern RCD protection will keep generating observations, and each EICR cycle, each alteration and each insurance renewal asks the same question again. Pairing the consumer-unit upgrade with the next planned electrical work — or the next void — buys the answer once, at the convenient moment.
The honest cost framing is asymmetric: the upgrade is a bounded, one-time expense; the alternative is an unbounded exposure measured in shock risk, fire risk and repeated remedial friction. Few line items in landlord compliance convert money into safety as directly as residual current protection — which is why the standards keep insisting on it.
Need the certificate itself?
The EICR (Electrical Safety Report) page covers cost, process and every UK area we serve.
FAQ
Related questions, answered
Who can carry out an EICR in your area?
A qualified and competent person — in practice an electrician who tests against BS 7671, typically registered with a scheme such as NICEIC or NAPIT. Landlords should ask for evidence of qualifications, scheme membership and insurance before booking.
What do the C1, C2, C3 and FI codes on an EICR mean?
C1 means danger present, immediate action required. C2 means potentially dangerous, remedial work needed. FI means further investigation required. C3 is an improvement recommendation only. A report with any C1, C2 or FI is unsatisfactory; C3s alone still pass.
Do tenants get a copy of the EICR?
In England, yes: existing tenants within 28 days of the inspection, new tenants before occupation, and prospective tenants within 28 days of a request. your local council can also demand a copy, which must be supplied within 7 days.
Is an EICR legally required for rentals in your area?
In England, yes: private landlords must have a satisfactory EICR renewed at least every 5 years. Scotland requires an EICR as part of the Repairing Standard. In Wales, the Renting Homes (Wales) Act 2022 regime requires electrical safety testing at least every 5 years. Northern Ireland currently has no equivalent general duty for private tenancies, though safety obligations still apply.
How long does an EICR take?
Usually 2 to 4 hours for a typical flat or house, longer for larger properties or older installations. Power is switched off circuit by circuit during testing, so tenants should expect short interruptions.
What information does an EICR contain?
The report identifies the property and the extent of the inspection, records test results per circuit, lists observations with C1/C2/C3/FI classifications, states an overall satisfactory or unsatisfactory outcome, and gives the recommended date of the next inspection.
Book it
Ready to act on this? The pillar page covers the certificate end to end, with every UK area linked: EICR (Electrical Safety Report).