When it comes to Electrical Installation Condition Reports (EICRs), the recommended re-inspection interval is one of the most common points of confusion. Recently, some electricians have been marking plastic consumer units (CUs) down to a 3-year inspection cycle, but is that correct — or even required?
Key Takeaways (60-Second Summary)
- Plastic consumer units aren’t banned — they can remain in service if safe.
- New domestic installs must be metal (since 2015 Amendment 3).
- Rental properties: Legally require an EICR every 5 years, not 3.
- Shorter intervals (e.g. 3 years) should only be recommended if specific risks are found (overheating, poor workmanship, high-risk location).
- Non-domestic settings: Plastic is still permitted but now a rarer choice, usually for high-IP environments.
- Metal is the default in most new installs due to durability and fire resistance.
What the Regulations Actually Say
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Owner-occupied homes: Guidance Note 3 suggests a maximum of 10 years between inspections.
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Private rented properties (PRS): The Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020 make it a legal requirement for landlords to have a valid EICR at least every 5 years.
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Commercial and industrial premises: Typically 5 years, though higher-risk environments may be shorter.
👉 The material of the consumer unit (plastic vs metal) does not change these baseline intervals in law.
Why Plastic Consumer Units Get Flagged
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In 2015, Amendment 3 of BS 7671 introduced a requirement for new consumer units in domestic dwellings to be made from non-combustible (metal) material when installed inside a property.
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This was in response to fire incidents linked to poor terminations and overheating in plastic boards.
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As a result, some electricians see any plastic CU as a higher risk, even if it’s perfectly serviceable and safe when installed correctly.
When a 3-Year Interval Could Be Justified
There are valid cases where an inspector might recommend a shorter interval, for example:
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Plastic CU under a wooden staircase (higher fire risk location).
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Signs of overheating or thermal damage on the board.
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Poor installation workmanship (loose terminations, overloading).
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Vulnerable occupants or higher-risk settings (e.g. HMOs, supported living).
In these cases, reducing the interval is about managing risk, not following a blanket rule.
The EICR Form: Justification Required
Every EICR has a box for:
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“Recommended interval until next inspection”, and
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“Reason for recommendation”.
If an electrician reduces the interval (e.g. from 5 years down to 3), they should state why. A simple blanket statement like “Plastic CU present — 3 years” isn’t really good enough; it should be backed up by specific risk factors.
Plastic vs Metal Consumer Units: Domestic and Non-Domestic Use
| Setting | Plastic Consumer Units | Metal Consumer Units |
|---|---|---|
| Domestic (dwellings, inside the property) | ❌ Not permitted for new installs since BS 7671:2015 (Amendment 3). Existing boards can remain in service if safe. | ✅ Required for new installs. Non-combustible to reduce fire spread risk. |
| Domestic (outside / outbuilding / garage / shed) | ✅ Acceptable where a high IP rating (e.g. IP65) is needed. | ✅ Common choice. May corrode in damp environments but still widely used. |
| Private Rental Sector (landlords) | ❌ New installs must be metal indoors. Existing plastic boards do not automatically need replacement. | ✅ Required for compliance on new installs inside the dwelling. |
| Commercial / Industrial premises | ✅ Still permitted, but now a rarer choice — usually only where a high IP rating or corrosion resistance is required. | ✅ Bulk of new installs remain metal due to robustness, fire containment, and durability. |
| Public buildings / higher-risk environments (schools, care homes, etc.) | ⚠️ Possible if location demands high IP, but uncommon and usually policy-driven against. | ✅ Preferred — stronger fire safety case and compliance with most policy requirements. |
Plastic in Non-Domestic Installations
While plastic consumer units and enclosures are still permitted outside of dwellings, they are not the default choice.
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Metal remains the most common specification for new commercial and industrial installations.
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Plastic is usually the exception, chosen specifically where a higher IP rating is essential — for example, wash-down areas, chemical environments, or outdoor locations.
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Many manufacturers now offer metal IP-rated boards, so plastic is becoming a more niche decision than it once was.
👉 Bottom line: Plastic is still an option in non-domestic settings, but usually only where IP performance outweighs the benefits of metal.
FAQs on Plastic Consumer Units
Do I need to replace my plastic consumer unit?
Not automatically. If it’s in good condition, installed correctly, and shows no signs of overheating or damage, it can remain in service. New installs inside dwellings must be metal, but there is no legal requirement to rip out a safe, existing plastic board just because of its material.
Are plastic consumer units illegal?
No. The 2015 regulation change only applies to new consumer units installed inside domestic properties. In non-domestic environments (offices, workshops, industrial sites), plastic enclosures are still permitted, though less common today.
Will my EICR fail if I have a plastic consumer unit?
Not necessarily. The presence of a plastic board alone is not a code-worthy defect. It may, however, influence the inspector’s judgment about re-inspection intervals if it’s located in a higher-risk position (e.g. under a wooden staircase) or shows signs of stress.
I’m a landlord — my EICR says 3 years because I’ve got a plastic CU. What do I do?
Legally, you only need an EICR every 5 years under the Private Rented Sector regulations. If your electrician has recommended 3 years, ask them to explain and record their reasoning. If they’ve found actual defects, you need to repair those now — not simply wait for the next inspection.
Are metal consumer units safer than plastic ones?
They’re more resistant to fire spread, which is why they’re now required for new domestic installs. But safety ultimately comes down to good workmanship and tight connections. A poorly terminated cable in a metal board is just as much of a risk as in a plastic one.
Bottom Line
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Plastic consumer unit ≠ automatic 3-year EICR.
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Law trumps opinion: For rentals, 5 years is the legal minimum.
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Shorter intervals should always be justified by specific risk factors, not just the material of the board.
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In non-domestic settings, plastic is still permitted but usually only chosen for high-IP applications.
Further reading: Electrical Safety First – Best Practice Guide 1 (Issue 5, Jan 2023): Replacing a Consumer Unit in Domestic and Similar Premises .
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