The rules, briefly, and one correction.
The current standard is BS 7671:2018+A4:2026, published on 15 April 2026 and mandatory from 15 October 2026, when the previous version is withdrawn. It is still the 18th Edition. Worth knowing that Amendment 4's headline changes cover battery storage, ICT earthing, Power over Ethernet and medical locations, so none of them forces a domestic board upgrade. All RCBO boards are best practice rather than a legal requirement, a dual RCD board remains compliant, and a plastic enclosure is not retrospectively a fault. We break all of that down properly on our Peterhead consumer unit page.
The correction, because it has appeared on Scottish pages including our own previously. Scotland has no competent person scheme and no Building Control notification. Those are England and Wales mechanisms, as is Part P, which does not apply here. In Scotland the framework is the Building (Scotland) Regulations and Building Standards, administered for Fraserburgh by Aberdeenshire Council. No building warrant is required to replace a consumer unit in an existing house, but the work must comply with BS 7671 and be tested and certified, which is what your certificate evidences.
One point that genuinely differs if you let property here: arc fault detection devices are required on socket circuits up to 32 A in HMOs, high rise residential, purpose built student accommodation and care homes, and only recommended in an ordinary dwelling. A licensed HMO therefore has a requirement the identical flat next door does not. Landlords also need a satisfactory EICR at least every five years under the Repairing Standard, with a copy to tenants.
And one duty that is real but routinely overstated. Since 1 March 2024 the Repairing Standard has required one or more RCDs rated at no more than 30 mA in the main consumer unit, normally covering the socket outlet circuit as a minimum, with the precise requirement depending on the installation. It does not require every circuit to be RCD protected, and it does not automatically fail a split load board, which has RCDs covering the socket circuits and will generally comply. What it does catch is a let property with no RCD protection at all. If you have been told a compliant board now fails, ask which paragraph that comes from.