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Ask ten electricians whether AFDDs are mandatory and you will get ten different answers. Some swear they are required on every board change. Some think they are still just a recommendation. A few are convinced a new rule lands in October 2026. On a normal house that confusion costs you nothing. On a care home or a house in multiple occupation, getting it wrong can mean a failed inspection, an awkward call with the responsible person, and a liability you do not want your name attached to if there is ever a fire.
So here is the straight answer, with the guesswork stripped out. Are AFDDs mandatory? Yes, but only in specific buildings, and the rule is older than most people think.
AFDDs are mandatory for socket circuits up to 32A in HMOs, purpose-built student accommodation, care homes and higher-risk residential buildings. They have been since Amendment 2 in September 2022, not from 2026. Everywhere else they are recommended.
Yes, AFDDs Are Mandatory, But Only in Specific Buildings
Arc Fault Detection Devices are required, not optional, for single-phase AC final circuits supplying socket-outlets rated at 32A or less in four types of premises:
- Houses in multiple occupation (HMOs)
- Purpose-built student accommodation
- Care homes
- Higher-risk residential buildings (broadly, over 18 metres tall or more than six storeys)
In those buildings you must fit an AFDD to the relevant socket circuits. The device has to conform to BS EN 62606. This is not a grey area and it is not new.
It Has Been the Rule Since 2022, Not 2026
This is where most of the confusion comes from. The requirement came in with Amendment 2 to BS 7671, which became mandatory on 27 September 2022. If you have been signing off HMO and care home work since then without AFDDs on those socket circuits, that work did not meet the standard.
You may have heard that Amendment 4 in 2026 makes AFDDs mandatory. That is not quite right. Amendment 4 is widening where AFDDs are required, pushing beyond dwellings toward more higher-risk situations. The direction of travel is more circuits, not fewer. The exact new categories are set out in the published amendment, so check the current wording before you quote a specific case to a client, rather than trusting a forum post. Our guide to Amendment 4 covers the wider changes landing this year.
"AFDDs become mandatory in October 2026." Not true. They have been mandatory for the four premises types above since 27 September 2022. October 2026 is the Amendment 4 changeover date, which widens the scope further.
Where AFDDs Are Only Recommended
Outside those higher-risk premises, in an ordinary home or most commercial work, AFDDs are recommended, not required. You can leave them out. What you cannot do is leave them out and stay silent about it. If a client asks for a board with no arc fault protection, that is their call, but the sensible move is to record that you offered it and that it was declined, so the decision is on paper and not on you.
That habit, writing down what you fitted and what you did not and why, is the difference between paperwork that protects you and paperwork that hangs you out to dry when someone reviews it a year later.
What This Means on the Job
None of this is hard once you know the rule. The trap is the record keeping. On the Electrical Installation Certificate or the EICR you need the circuit details, the protective devices and any coded observations to actually match what is on the wall. An inspector who sees an HMO socket circuit with no AFDD and no explanation has an easy C2 to write.
This is the boring part of the job that quietly decides whether your work stands up, and it is exactly the part LedgerCert is built to make quick. You produce a clean, current EIC or EICR on your phone, record the circuits and observations properly, and export a professional PDF, all free to create and download. When the rule is this specific, having the certificate right is not admin for its own sake. It is the thing that proves you did the job properly.
AFDDs are mandatory for socket circuits up to 32A in HMOs, student accommodation, care homes and higher-risk residential buildings. Mandatory since Amendment 2 in September 2022, not 2026. Amendment 4 is widening the scope this year, so check the latest wording. Everywhere else they are recommended, and if you leave them out, record that you did and why. Whatever you fit, make the certificate match the installation.
Frequently Asked Questions
Are AFDDs mandatory in a normal house?
No. In an ordinary single dwelling AFDDs are recommended, not required. They are only mandatory for socket circuits up to 32A in HMOs, purpose-built student accommodation, care homes and higher-risk residential buildings.
When did AFDDs become mandatory?
With Amendment 2 to BS 7671, which became mandatory on 27 September 2022. It was not introduced by Amendment 4 in 2026.
Which standard must an AFDD meet?
It must conform to BS EN 62606.
Does Amendment 4 change the AFDD rules?
Amendment 4 (2026) widens where AFDDs are required, extending the scope beyond dwellings. Check the published amendment for the exact categories before applying it to a specific job.
Can I leave AFDDs out if a client does not want them?
Outside the mandatory premises, yes. The sensible step is to record that arc fault protection was offered and declined, so the decision is documented on the certificate.
How LedgerCert Helps
LedgerCert is a free web app for UK electricians to create, manage and export digital compliance certificates. You can produce a clean, current EICR, EIC or Minor Works Certificate on your phone or tablet, record the circuits, protective devices and observations properly, and export a professional PDF. It is free to create and download, and it works offline on site.
When a rule is as specific as the AFDD requirement, the thing that protects you is a certificate that matches the installation. That is exactly what LedgerCert is built to make quick, so you can get the rule right, record it cleanly, and move on to the next job.