4.5 Inspection Methods: The Senses, Verifying Items & IP Classification
Key Takeaways
- Inspection is carried out mainly by sight, supported by touch, smell and hearing; taste is never used, and touch is used only on parts that are safe to handle
- On an EIC the schedule of inspections items are marked acceptable or not applicable; on an EICR they carry the observation codes C1, C2, C3, FI, plus LIM for a limitation
- At initial verification an unsatisfactory item must be corrected and the affected inspection and tests repeated before the certificate is issued - there is no coding system for new work
- At periodic inspection an unsatisfactory item is recorded as a coded observation; the inspector does not normally rectify, but a C1 requires immediate action to make safe
- IP2X or IPXXB is the standard for basic protection by an enclosure or barrier; IP4X or IPXXD applies to a readily accessible horizontal top surface
Inspection Is a Sensory Examination
Assessment criterion 3.3 asks you to describe the appropriate human senses required for a particular inspection. It is a favourite exam item because the answer is short and precise.
| Sense | What it detects | Notes |
|---|---|---|
| Sight | The great majority of findings: damage, corrosion, missing barriers, incorrect cable type or routing, absent or illegible labelling, poor terminations, signs of overheating, IP degradation | The primary sense — inspection is fundamentally a visual activity |
| Touch | Loose accessories, insecure glands and enclosures, warm equipment indicating overload or a high-resistance joint | Only on parts that are safe to touch; the installation should be isolated, and a suspected hot part is checked with the back of the hand or a thermal instrument |
| Smell | Overheated PVC or bakelite, burnt insulation, the sharp smell of ozone from arcing | Often the first indication of a fault inside a sealed enclosure |
| Hearing | Arcing or buzzing at a loose terminal, humming from loose laminations, a chattering RCD or contactor | Useful on energised switchgear before isolation |
Taste is never used. If an exam option offers it, that option is wrong.
Two practical points follow. First, most inspection is carried out with the installation isolated, which is why touch is available at all. Second, several of these senses are only useful before isolation — you cannot hear arcing in a dead board — so a walk-round of the energised installation, made safely and without opening anything, is a legitimate part of the process.
Verifying and Marking Each Item (AC3.2)
Every item on the schedule of inspections has to be resolved to an outcome. How you mark it depends on which document you are producing, and candidates lose marks by carrying the EICR codes onto an EIC.
On an Electrical Installation Certificate
New work either complies or it does not. Each item is marked as acceptable (a tick), or N/A where the item does not apply to this installation — for example supplementary bonding in a location that does not require it. There is no C1, C2, C3 or FI on an EIC. A deficiency is not coded; it is corrected.
On an Electrical Installation Condition Report
The installation already exists, so each item is judged on condition and marked with one of:
| Mark | Meaning |
|---|---|
| Acceptable condition | The item was inspected and is satisfactory |
| C1 | Danger present — risk of injury |
| C2 | Potentially dangerous |
| C3 | Improvement recommended |
| FI | Further investigation advised |
| N/A | The item does not apply to this installation |
| LIM | The item was not inspected because of an agreed or operational limitation |
LIM is not a pass. It records that the item was not examined, and it must be consistent with the limitations stated on the front of the report. Marking an item acceptable when it was never seen is a serious reporting failure. The coding system itself is covered in detail in section 10.3.
While inspecting a new installation before energising, you find a consumer unit with a missing blanking piece leaving a live busbar accessible. What is the correct action?
Dealing With an Unsatisfactory Item (AC3.4)
Assessment criterion 3.4 splits deliberately into 3.4a and 3.4b, because the answer is genuinely different for the two processes.
3.4a — During initial verification
The installation is not yet in service and the inspector is certifying compliance. So:
- Stop and report the deficiency to the designer or installer, and to the client where the work is not the inspector’s own.
- Do not proceed with testing past the point where continuing would be unsafe or would produce meaningless results — for example, do not energise an installation with a broken protective conductor.
- Have the defect corrected.
- Repeat the affected inspection and any test invalidated by the correction. Re-terminating a circuit protective conductor invalidates the R1+R2 for that circuit, and therefore the Zs derived from it.
- Issue the certificate only when the work complies. An EIC declaring compliance for work known to be defective is a false document.
Where the defect is in the existing installation that new work connects to — inadequate main bonding, for example — it must be recorded, the client informed in writing, and the adequacy of the existing arrangements for the new work resolved before the new work is put into service.
3.4b — During periodic inspection
The installation is in service and belongs to somebody else. The inspector reports; they do not normally repair.
- Record the observation with a clear description of what and where, and assign the correct code.
- For a C1, take immediate action to make safe — typically isolating and securing the dangerous part — and notify the duty holder immediately and in writing. This is the one case where the inspector intervenes rather than merely reports.
- For a C2, record it and inform the client promptly; remedial action is urgent but the item is not an immediate danger.
- Where the item cannot be assessed, record FI and explain why.
- Let the outcome follow the codes — the inspector does not choose the overall result independently.
Any remedial work carried out is a separate job with its own certification — a Minor Works Certificate, or an EIC where new circuits are installed.
The IP Classification System (AC3.5)
IP stands for Ingress Protection, defined in BS EN 60529. The code is two digits: the first for solid bodies, the second for liquids. An X means the digit is not specified.
| First digit | Protection against solid objects |
|---|---|
| 0 | None |
| 1 | Solid objects greater than 50 mm (back of the hand) |
| 2 | Solid objects greater than 12.5 mm (a finger) |
| 3 | Solid objects greater than 2.5 mm (a tool) |
| 4 | Solid objects greater than 1 mm (a wire) |
| 5 | Dust-protected |
| 6 | Dust-tight |
| Second digit | Protection against water |
|---|---|
| 0 | None |
| 1 | Vertically falling drips |
| 2 | Drips at up to 15° from vertical |
| 3 | Spraying water |
| 4 | Splashing water from any direction |
| 5 | Water jets |
| 6 | Powerful water jets |
| 7 | Temporary immersion |
| 8 | Continuous immersion |
An optional additional letter describes access to hazardous parts specifically: A back of hand, B finger, C tool, D wire. That is where IPXXB and IPXXD come from — they specify the access protection without making any claim about dust or water.
Where BS 7671 uses IP codes
| Requirement | Code |
|---|---|
| Basic protection by an enclosure or barrier — no access to live parts with a finger | IP2X or IPXXB |
| The readily accessible horizontal top surface of a barrier or enclosure — no access with a wire | IP4X or IPXXD |
| Zones 1 and 2 of a location containing a bath or shower | IPX4 |
| Where water jets are used for cleaning, for example in some commercial kitchens | IPX5 |
The horizontal top surface rule catches people out. A consumer unit lid protects a finger from the front, but the top face is where a dropped screw or a length of wire will land — so it gets the tighter requirement. During inspection, look for missing blanks, broken knockouts, unglanded entries and cracked enclosures: all of them degrade the IP rating that the equipment was selected to provide.
A distribution board is fitted at eye level in a plant room. Which IP requirement applies to its readily accessible horizontal top surface?
Which combination of senses would most likely detect a loose, arcing terminal inside an energised switchgear enclosure before it is opened?