Four condition codes determine whether an electrical installation is safe or not. Each one carries a different obligation. This guide explains what they mean, what you must do when you find one, and what the law requires of landlords when the report comes back Unsatisfactory.
An Electrical Installation Condition Report uses a small set of standardised codes to describe the condition of each observation. These codes come from BS 7671. the IET Wiring Regulations. and their meanings are not matters of opinion. An electrician cannot upgrade a C2 to a C3 because the client seems unbothered. The code describes the condition of the installation, not the client's tolerance for risk.
The codes are assigned at the observation level. The overall EICR outcome. Satisfactory or Unsatisfactory. is then determined by what codes appear on it.
| Code | Meaning | Makes EICR Unsatisfactory? |
|---|---|---|
| C1 | Danger present. risk of injury | Yes |
| C2 | Potentially dangerous | Yes |
| C3 | Improvement recommended | No |
| FI | Further investigation required | Yes |
A C1 code means danger is present and there is a risk of injury. This is the most serious code an electrician can assign. It is not a warning about what might happen. it describes a condition that presents a real risk right now.
Common C1 findings include: exposed live conductors, missing protective devices, damaged wiring with exposed cores, or a complete absence of earthing where earthing is required.
When a C1 is found, the electrician must advise the client in writing not to use the affected part of the installation until remedial work has been completed and the installation re-inspected. This is a professional obligation, not an optional courtesy. If the electrician can make the installation safe on the spot. isolating the dangerous circuit, for example. they should do so. If they cannot, they must make the danger clear before they leave.
The client cannot simply note the C1 and carry on. Any electrician who discovers a C1 and says nothing has failed in their duty of care.
A C2 code means the observation is potentially dangerous. The risk is not immediate in the way a C1 is, but the defect could become dangerous. through deterioration, fault development, or interference by an untrained person.
Common C2 findings include: inadequate protection against mechanical damage, absence of RCD protection where it is now required, incorrect cable sizes, and wiring methods that do not meet current standards.
A C2 makes the EICR Unsatisfactory. The installation does not necessarily need to be shut down immediately, but remedial work is required. In a rental property, a landlord must complete that remedial work within 28 days, or sooner if the EICR specifies a shorter period.
The distinction between C1 and C2 matters in practice. A C1 requires you to tell the client to stop using the affected circuit. A C2 requires you to tell the client that work is needed. Both make the report Unsatisfactory. Neither gives the client or landlord the option to do nothing.
A C3 code means an improvement is recommended. The installation is not dangerous. It does not meet current standards in some respect, but it was installed under older regulations and is not creating a hazard in its current state.
C3 is the code that confuses clients most. They see it on the report and assume something must be done. It does not make the EICR Unsatisfactory. An EICR that contains only C3 observations comes back Satisfactory.
That said, a C3 is not meaningless. It is an observation that something could be improved. An electrician should explain what the observation is and let the client decide whether to act on it. The recommendation to improve is genuine. it is simply not a requirement.
Upgrading from C3 to compliant is often straightforward: adding RCD protection to an older installation, or replacing a socket outlet near a sink with an RCD-protected one. Whether to do it is the client's call.
FI stands for Further Investigation. It is used when the electrician cannot determine the condition of part of the installation during the inspection and testing. Something is unclear. concealed wiring, an inaccessible enclosure, an anomalous test result. and a condition code cannot yet be assigned.
FI makes the EICR Unsatisfactory. The installation is not cleared until the investigation is complete and the FI is resolved into a condition code (C1, C2, C3, or satisfactory).
FI is sometimes misused as a way to avoid making a difficult call. That is poor practice. FI should be used only where the electrician genuinely cannot inspect or test the item during the current visit. It is not a catch-all for observations that are borderline.
When an FI is raised, the scope of the further investigation must be clear. The client must understand what needs to be inspected, what access or work is required, and what the consequence of not investigating is.
The EICR does not just record condition codes. It must state the recommended time period for the next inspection and testing. For installations with no defects, this is typically 10 years for domestic and 5 years for commercial. For installations with C1 or C2 observations, the report should specify the period within which remedial work must be done.
Under the Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020, landlords must complete remedial work within 28 days of receiving an Unsatisfactory EICR. or within any shorter period stated in the report. They must then obtain written confirmation from the electrician that the work has been done and the installation is now satisfactory, and provide that confirmation to the tenant.
An EICR is not a document you file and forget. Every C1 and C2 on it represents a legally unresolved obligation until remedial work is done and confirmed.
Electricians using Quickler for EICR work record observations through a WhatsApp conversation. no app to install, no login to remember. The moment a C1 or C2 code is entered, it is flagged live on the dashboard. The office sees it in real time, not when the engineer returns at the end of the day.
This matters on C1 findings in particular. If an engineer raises a C1 at a rental property, the office can contact the landlord immediately rather than waiting for the PDF to land in an email inbox hours later. The dashboard uses red/amber/green status to make the severity visible at a glance across all live jobs.
PDF export happens at the end of the workflow. The certificate reaches the client by one-click email directly from the job record.
C1 means danger is present and there is a risk of injury. The electrician must advise the client not to use the affected part of the installation until remedial work is done. A C1 makes the EICR Unsatisfactory and requires immediate action.
C2 means potentially dangerous. the defect does not present immediate danger but could become dangerous. C3 means improvement is recommended but the installation is not dangerous. A C2 makes the EICR Unsatisfactory. A C3 on its own does not.
FI stands for Further Investigation. It is used when the electrician cannot determine the condition of part of the installation without additional testing or access. An FI makes the EICR Unsatisfactory until the investigation is complete and a condition code can be assigned.
Under the Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020, landlords must complete remedial work within 28 days of receiving the EICR. or sooner if the report specifies a shorter timescale. A C1 typically requires immediate action.
Quickler runs through WhatsApp. No app install, no training, first live EICR under a week.