A commercial EICR (Electrical Installation Condition Report) is the periodic inspection of the fixed wiring in a workplace, shop, office, warehouse or other non-domestic building, carried out under Chapter 65 of BS 7671 and reported on the same form as a domestic EICR. What differs is the scale, the legal driver and the method. IET Guidance Note 3 recommends a maximum interval of 5 years for most commercial premises, 3 years for industrial and 1 year for the highest-risk locations; the Electricity at Work Regulations 1989 place the duty to maintain the installation on the employer or occupier; and because a commercial installation may have dozens of distribution boards, the inspector samples circuits and agrees written limitations before starting.
- Intervals come from IET Guidance Note 3 Table 3.2: typically 5 years commercial, 3 years industrial, 1 year for swimming pools, petrol stations, caravan parks and similar.
- The legal duty is Regulation 4(2) of the Electricity at Work Regulations 1989: systems must be maintained so as to prevent danger. The EICR is the accepted evidence.
- Three-phase supplies, sub-mains, multiple distribution boards and sampling all need to be recorded properly on the schedules.
- Agree the extent and limitations in writing before starting, and exclude emergency lighting, fire alarms and other systems with their own standards.
- The most common commercial observations are missing circuit charts, borrowed neutrals, 13 A sockets without RCD protection and no main bonding to structural steel.
Is a commercial EICR a legal requirement?
No single regulation says "commercial premises must have an EICR every 5 years", in the way the Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020 do for rented housing. The duty is broader. Regulation 4(2) of the Electricity at Work Regulations 1989 requires that "all systems shall be maintained so as to prevent, so far as is reasonably practicable, such danger", and the Health and Safety Executive's guidance (HSR25) explains that regular inspection and testing is the way to establish whether maintenance is needed. The duty falls on employers, the self-employed and employees for matters within their control, enforced by the HSE and local authorities.
The Regulatory Reform (Fire Safety) Order 2005 adds a duty on the responsible person to take precautions against fire, and electrical faults are an ignition source every fire risk assessor looks for. Most commercial insurance policies require periodic inspection by a competent person, often on a 5-year cycle, and a claim can be refused where it is missing. The EICR satisfies all of these at once, which is why it is treated as a requirement in practice.
How often does a commercial property need an EICR?
The intervals are recommendations in IET Guidance Note 3 (Inspection and Testing), Table 3.2; BS 7671 itself gives no table, and Regulation 652.1 leaves the frequency to be determined from the type of installation, its use, the maintenance regime and external influences. They are maximum periods; the previous inspector can recommend a shorter one on the report, and the duty holder must justify the interval they use.
| Premises | Maximum period between inspections (GN3) |
|---|---|
| Commercial (offices, shops, restaurants, hotels, public houses, village halls, churches) | 5 years |
| Educational establishments | 5 years |
| Hospitals and medical locations (general areas) | 5 years |
| Industrial premises | 3 years |
| Agricultural and horticultural | 3 years |
| Leisure complexes (excluding swimming pools), theatres, cinemas | 3 years (cinemas 1 to 3 years) |
| Swimming pools, saunas | 1 year |
| Petrol filling stations, caravan parks, marinas, laundrettes | 1 year |
| Emergency lighting (fixed wiring) and fire alarm (fixed wiring) | 3 years and 1 year respectively, alongside the BS 5266/BS 5839 tests |
A change of use, a change of occupier, a significant alteration, flood or fire damage, or an insurer or purchaser request all justify a new inspection before the interval expires. Intervals for all property types are set out in How Often Is an EICR Required? Intervals by Property Type.
What is different about inspecting a commercial installation?
The form, codes and standard are identical to a domestic EICR (/guides/how-to-do-an-eicr-step-by-step). The differences are practical.
Three-phase supply and sub-mains
A typical commercial installation has a three-phase 400 V TN-C-S or TN-S supply, a main switch or switch-fuse, and sub-mains to several distribution boards. Each sub-main is a circuit in its own right and gets a line on the schedule of test results: cable type and size, the protective device at the origin, measured Zs at the sub-board (Zdb) and insulation resistance. Record phase rotation at each three-phase board, measure prospective fault current at the origin and each board, and check the breaking capacity of every device against it. Where a board's Zdb is high, every circuit on it inherits the problem, so investigate the sub-main before writing off twenty final circuits as C2.
Distribution board schedules
Every distribution board has its own schedule of test results and inspection schedule, headed with the board designation, location, supply device and Zdb. Circuits are identified by the board's own numbering, so the chart on the door matters; a board with no chart is the first observation on most commercial reports. Filling in the schedules is covered in Schedule of Test Results: How to Fill In Every Column.
Sampling
Testing every socket-outlet and luminaire in a 200-desk office is not practical, so Guidance Note 3 permits sampling. The inspector agrees an initial sample of accessories, commonly expressed as a percentage per circuit type, and increases it, up to 100 per cent, if defects are found. Dead tests are still performed at the board on each circuit; where a circuit could not be tested because equipment could not be isolated, that is recorded as a limitation, not left blank. See EICR Sampling and Limitations Explained: Extent, LIM and N/V.
Access and live working
Dead testing means switching things off, so agree a time, obtain a permit to work where the site requires it, and warn the occupier about servers, alarms, refrigeration and emergency lighting that will be affected. Regulation 14 of the Electricity at Work Regulations prohibits live working unless it is unreasonable for the conductor to be dead, and inspecting inside a live 400 V board with the covers off is exactly the situation it addresses.
What should be agreed in writing before the inspection?
BS 7671 requires the extent and any limitations to be agreed with the person ordering the work and recorded on the report. On a commercial job do this in writing before you arrive, covering:
- Extent: which buildings, floors and boards are included; whether tenant fit-outs, outbuildings, external lighting and car park supplies are in or out.
- Sampling: the percentage of accessories to be inspected.
- Circuits that cannot be isolated: IT, security, refrigeration, life-safety systems, process plant, and what will be recorded for them.
- Exclusions: emergency lighting (BS 5266-1), fire detection and alarm (BS 5839-1), lightning protection (BS EN 62305), lifts, machinery internal wiring, generators and UPS output, HV switchgear, and portable appliances (covered by in-service inspection and testing, see PAT Testing Guide UK: Intervals, Tests and Records).
- Access: locked rooms, ceiling voids, plant rooms, roofs and any area needing a permit.
The report should say what was excluded and why, and recommend that the client obtains current certificates for the excluded systems; see Emergency Lighting Certificate: BS 5266-1 Testing and Records and Fire Alarm Certificate BS 5839-6: Grades and Categories.
What do insurers and landlords require?
Insurers typically require inspection and testing by a competent person at intervals not exceeding a stated period, commonly 5 years and sometimes 3 for higher-risk trades, with defects rectified; some ask for the report at renewal. An Unsatisfactory report that has sat in a drawer for two years is worse than no report, because it documents that the duty holder knew.
In leased premises the lease decides who commissions the EICR. Under a full repairing and insuring lease the tenant maintains the installation within the demise and the landlord the common parts and incoming supply; both are duty holders under the Electricity at Work Regulations for the parts they control. Facilities managers should hold the EICR, remedial certificates, emergency lighting and fire alarm certificates and PAT records together, because an assessor, insurer or HSE inspector will ask for all of them. What happens after an Unsatisfactory result is in Unsatisfactory EICR: What Happens Next (Landlords & Electricians).
What defects are found most often in commercial installations?
The codes are the same as for any EICR: C1 danger present, C2 potentially dangerous, C3 improvement recommended, FI further investigation required; C1, C2 or FI makes the report Unsatisfactory (/guides/eicr-codes-explained-c1-c2-c3-fi). The observations that recur on commercial reports are:
| Observation | Typical code | Notes |
|---|---|---|
| No circuit chart or inaccurate labelling at a distribution board | C3 | C2 where circuits cannot be safely identified for isolation |
| Borrowed neutral (neutral shared between circuits on different protective devices) | C2 | Isolating one circuit leaves its neutral live from the other; common on lighting after alterations |
| 13 A socket-outlets without 30 mA RCD protection | C3 | C2 where sockets could supply equipment outdoors, in wet areas or on construction-type work; the 411.3.3 risk-assessment exception must be documented |
| No main protective bonding to structural steel or incoming services | C2 where the metalwork is extraneous-conductive | Confirm with a bonding conductor continuity test before coding; record as FI if it cannot be established |
| Missing blanks, broken covers or exposed live parts in boards | C1 or C2 | C1 where live parts are accessible to touch |
| Undersized main earthing conductor or main bonding conductors | C2 or C3 | Depends on the supply and the age of the installation |
| Thermal damage to terminals, discoloured busbars, signs of overheating | C2 | Investigate loose connections and loading |
| Inadequate IP rating in wash-down, kitchen or external areas | C2 | Water ingress into live parts |
| Sub-mains in unsupported SWA or with glands not earthed | C2 or C3 | Check gland continuity and support |
| Unidentified or abandoned cables left connected | FI | Common after tenant fit-outs |
Borrowed neutrals deserve a word. Where two lighting circuits share a neutral, the neutral of the switched-off circuit still carries return current from the live one, and an electrician who has isolated "their" circuit gets a shock at the neutral. GN3 and Electrical Safety First's Best Practice Guide 4 both treat this as C2. They show up when a lighting circuit's insulation resistance test fails until the adjacent circuit is also isolated.
Structural steel bonding comes up because portal-frame warehouses and steel-framed offices have exposed steel that may or may not be extraneous. Test between the steel and the main earthing terminal: a very low reading with no visible bonding conductor suggests it is connected somewhere, a high reading suggests it is not extraneous, and a reading in between needs judgement. The reasoning is in What is main protective bonding? Explained.
How Certio helps
Certio produces the EICR, EIC, Minor Works certificate and PAT records on the BS 7671 model forms and turns them into branded PDFs. Photograph the consumer unit and the circuit schedule drafts itself; point the phone camera at a Megger MFT-X1 and the reading goes straight into the schedule of test results, or dictate it while your hands stay on the probes. Suggested observation wording with the regulation reference is there for you to check and confirm. The judgement stays yours; the typing goes. Starter is free for 7 days, then £5 a month.