Fixed Wire Testing: Observation Codes, C1, C2, C3 and FI Explained

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Date: Tue 08 Mar 2016

Observations could be things which are wrong with your installation that need rectifying and they are coded.

Fixed Wire Testing is a legal requirement and it is governed by the IET Wiring Regulations Seventeenth Edition also referred to as BS 7671. Your electrical contractor will supply you with an Electrical Installation Condition Report (EICR) on completion of testing. This report will indicate any problems or 'observations' which are coded according to their risk factor, but what do they mean?

Observations are recorded on page two of your Fixed Wiring Report, also known as as an Electrical Installation Condition Report (EICR). They are things which are wrong with your installation that need rectifying and they are coded according to their danger level, using the codes C1, C2, C3 and FI.

Code C1

A Code 1 (C1) observation means 'Danger present. Risk of injury. Immediate remedial action required.' It is an immediate threat and should be rectified or made safe as soon as possible. An example of a C1 defect would be accessible live conductors due to damage, poorly modified enclosures or removed maintenance panels. Incorrect polarity would also attract a code C1 as it may allow conductive parts, not normally expected to be live, to become live.

The presence of a code C1 warrants immediate action to be taken - the Intersafe engineer will inform the duty holder or responsible person for the installation immediately, both verbally and in writing, of the risk of injury that exists. Access to the faulty circuit may even be blocked, or the circuit turned off until the the defect is fixed.

Code C2

A Code 2 (C2) is not as severe as a C1, but is still a potentially dangerous defect. These might be things that don't pose an immediate threat but are likely to become a danger in the future. A C2 is described as 'Potentially dangerous - urgent remedial action required.'

The phrase "potentially dangerous", in the C2 code is designed to point towards a risk of injury from contact with live parts after a sequence of events. A sequence of events could mean that an individual may gain access to live parts through a day to day task that would not be expected to give access to live parts.

Code FI

An observation code FI is described as 'Further investigation required without delay.' This means that your electrical contractor has observed something whilst carrying out the testing for instance emergency lights seem very dim. This might not have been covered in the report so they have noted it separately as code FI.


Codes C1 and C2 attract unsatisfactory report findings and you'll have to have these defects rectified in order to prove compliance. A report could also be classed as unsatisfactory if the only fault codes are FI. An example would be when there are lots of circuits that are not verified at the time of testing, this is because the inspector would not be able to categorically say that these circuits are safe or not.

Code C3

Code 3 is described as 'Improvement recommended.' This means it does not comply with the regulations but isn't actually dangerous. For example, the installation may not comply with the current version of the regulations or may have damaged fittings that do not have exposed live parts. A code C3, in itself, should not warrant an overall unsatisfactory report.

You will need to address C1, C2 and FI faults on your report in order to achieve compliance. However it's always good practice and usually well worthwhile considering rectifying all faults on site. Remember you aren't obliged to use the same electrical contractor to test and to carry out remedial repairs and you don't need to have the whole installation re tested after the repairs have been completed.

Electrical Installation Condition Report (EICR)

Once faults have been rectified and your electrician has issued you with the relevant paperwork, Electrical Installation Certificate (EIC) or Minor Works Certificate (MW) these should be kept together with the Electrical Installation Condition Report (EICR) to prove all faults have been rectified in accordance with BS7671.

If the unthinkable happens and someone receives a shock from part of your installation or if there is an electrical fire in your building then a court, inquest or insurance company will certainly want to see this EICR Fixed Wire Testing report which makes it very important document.

Specialist Electrical Contractors

Intersafe specialise in providing tailored electrical testing solutions in Fixed Wire Testing, PAT Testing, Emergency Light Testing and Thermal Imaging. If your electrical installation testing is due, or you are not sure what you need, please contact a member of the Intersafe team on 02380 236200 or email

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