ELECTRAGUARD.UK

Short Answer:
Only in specific types of high-risk buildings.
Under BS 7671:2018+A2:2022, AFDDs are mandatory for final circuits up to 32A supplying:

1. High-Risk Residential Buildings (HRRBs)
This includes:
-High-rise apartment blocks
-Buildings over 18m in height
-Buildings containing vulnerable occupants
2. Houses in Multiple Occupation (HMOs)
Any shared home or rental property classed as an HMO requires AFDD protection on relevant circuits.
3. Purpose-Built Student Accommodation
4. Premises with Vulnerable Occupants
Such as:
-Care homes
-Supported living
-Medical accommodation
-Assisted-living facilities
If your property falls into one of these categories, AFDDs are required by regulation.

🔳 When Are AFDDs Recommended (But Not Mandatory)?
In all other domestic properties, AFDDs are not compulsory, but the regulations list them as “recommended” for increased protection.
This includes:
-Standard houses
-Bungalows
-Flats below 18m
-Renovations
-Extensions
-Consumer unit upgrades
Electricians must “consider the use of AFDDs” during the design stage, but homeowners are free to accept or decline them.

🔲 When Are AFDDs Optional?
AFDDs are optional when:
-Installing a new consumer unit in a typical house
-Rewiring a standard domestic property
-Adding a new circuit (e.g., for an EV charger or extension)
-Carrying out alterations or minor works
-The risk level is low and the customer declines the upgrade
AFDDs can be fitted to all, some, or none of the circuits — they are circuit-specific.
Common circuits electricians may recommend protecting:
-Socket ring circuits
-Bedroom circuits (because of sleeping risk)
-Loft circuits
-Garage and outbuilding circuits
-High-risk appliance circuits (washer, dryer, dishwasher)

💷 Are AFDDs Expensive?
Typical costs (2025):
-£80–£150 per device
-Installed as AFDD/RCBO units
-Often added during a consumer unit replacement
Homeowners often choose partial protection to balance cost and safety.

🧰 Why Aren’t They Mandatory in All Homes?
There are three main reasons:
-Cost — AFDDs are significantly more expensive than MCBs/RCBOs
-Not needed in most standard domestic layouts
-Fire risk in typical UK homes is lower compared to high-rise or high-risk buildings
Regulations aim to protect the highest-risk buildings first.

⭐ Final Advice
If your home is not one of the mandatory building types, the decision is yours. AFDDs offer excellent fire protection, but costs may influence whether you fit them to:
-All circuits
-Only key circuits
-None at all

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Call today for a free, no-obligation estimate and see why so many homeowners and businesses rate us as their go-to electrician.

24/11/2025

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