Part P Building Regulations Explained: Electrical Safety in Dwellings

What Part P Actually Says

Part P is the part of the Building Regulations that covers electrical installations in dwellings in England and Wales. It does not apply in Scotland, Northern Ireland, or in commercial premises and factories. The whole of Part P itself is remarkably short — a single paragraph:

Reasonable provision shall be made in the design and installation of electrical installations in order to protect persons operating, maintaining or altering the installations from fire or injury.

That is the entire legal requirement. Everything else you read about Part P — the approved document, the schemes, the lists of notifiable work — is guidance on how to demonstrate compliance with that one sentence.

Part P sits alongside other parts of the Building Regulations: Part A (structure), Part B (fire safety), Part L (energy efficiency), Part M (access), and so on. It earned the letter “P” simply because that was the next available letter when it was introduced.

Where Part P Applies

Part P applies to all electrical work in dwellings, including:

• Houses and bungalows
• Flats and maisonettes
• Common parts and shared staircases of blocks of flats
• Outbuildings supplied from a dwelling — garden sheds, garages, greenhouses
• Land associated with the dwelling — outdoor lighting, garden sockets

It does not apply to offices, shops, factories, business units, or any other non-domestic premises. Those installations still have to be safe and compliant with BS 7671 (the Wiring Regulations), but Part P itself is not the legal driver.

The scope is also broad in another sense — Part P covers everything from a complete rewire down to swapping a light switch. The reasoning is sensible: any electrical work in someone’s home should be safe, regardless of how trivial it seems.

Approved Document P and BS 7671

The Approved Document P is the practical guide published alongside the regulation. It explains how to comply with that single paragraph and gives examples, definitions, and procedural detail. Importantly, the Approved Document is guidance, not law — you are free to comply with Part P in other ways, provided the installation is safe.

In practice, the most common route to compliance is to follow BS 7671 (the IET Wiring Regulations). While Part P does not mandate BS 7671, designing and installing in line with it is the most straightforward way of demonstrating that the installation will not cause fire or injury. Our essential electrical safety guide explains how BS 7671 ties into day-to-day site practice for ECS card holders.

You should also remember that electrical work rarely happens in isolation. Channels in walls, holes through joists, fire-stopping around cables, lighting energy efficiency, and the height of socket outlets and switches all engage other parts of the Building Regulations — Parts A, B, L, and M in particular. Compliance with Part P does not exempt you from these.

Notifiable Work in England

Although Part P applies to all electrical installations, only a short list of jobs needs to be notified to Building Control. In England, that list is:

1. The installation of a new circuit
2. The replacement of a consumer unit
3. Any addition or alteration to existing circuits in a special location

A “special location” is essentially a room containing a bath or shower, but only the area within defined zones — broadly, the volume above the bath or shower tray and within 600 mm horizontally of it, up to a height of 2.25 m from finished floor level. Swimming pools and sauna heaters also count.

In a typical bathroom, the items likely to fall inside that zone are limited:

• Electric showers — almost always notifiable
• Extractor fans within the zone (most ceiling-mounted ones are not)
• Anything else mounted within 600 mm of the bath or shower

Lighting, towel rails, and shaver sockets are usually outside the zone. Note also that BS 7671 requires socket outlets to be at least 3 m horizontally from the boundary of the bath or shower zone — a separate Wiring Regulations rule, not Part P.

Everything else is not notifiable — that includes additions and alterations to anything else, and replacements, repairs, and maintenance anywhere.

In Wales, the older list still applies, so additional kitchen work and certain outdoor installations remain notifiable there.

The Three Routes to Notification

When work is notifiable, there are three legitimate ways to deal with it:

1. Self-certification via a Competent Person Scheme

Electricians who join a registered scheme — NICEIC, NAPIT, ELECSA, Stroma, and others — can self-certify their own notifiable work. They pay an annual scheme fee and a small per-notification charge (typically around £5), and the scheme handles the building control paperwork on their behalf. This route is only available for work the registered person has actually carried out themselves; it cannot be used to retrospectively sign off someone else’s installation.

2. Third-Party Certification

A non-registered installer can appoint a registered third-party certifier to inspect and test the work and issue the appropriate certification. In practice this option has very limited availability, as several of the major scheme operators have declined to offer it.

3. Building Control Notification

The installer (or homeowner) submits a building notice or full plans application directly to the local authority Building Control office, pays a fee — typically a few hundred pounds — and Building Control inspect as they see fit. This is the route most DIY householders take if they want to do the work themselves.

The fourth “option” — doing the work without telling anyone — is unlawful.

Common Misconceptions

A few myths come up regularly, and they cause real problems on site and in homes:

• “Part P courses” and “Part P qualified” do not exist. Part P is one paragraph; there is no exam, no qualification, and no certificate for it. Training courses advertised under that name are simply general electrical courses. Membership of a competent person scheme is a separate matter that involves your existing electrical qualifications and assessed work.
• You cannot “call in an electrician to sign it off” afterwards. Notifiable work must be notified before it starts. Once the work has been done by an unregistered person, no electrician can lawfully self-certify it.
• The remedy for unnotified work is regularisation. Building Control offer a regularisation procedure for work carried out without notification. It typically costs around double the normal fee, and inspectors may require you to expose concealed cables and accessories so the installation can be properly inspected and tested.

For a refresher on the broader safety knowledge needed alongside Part P, see our guides on electrical safety awareness for site workers and the complete PPE guide for electricians.

Practical Compliance Checklist

When planning domestic electrical work, run through these points:

• Is the property a dwelling or associated building? If yes, Part P applies.
• Does the work fall into one of the three notifiable categories (new circuit, consumer unit replacement, special location alteration)?
• If notifiable, which route will you use — competent person scheme, third-party certifier, or direct to Building Control?
• Are you also engaging other Building Regulations parts — Part A for structural penetrations, Part B for fire-stopping, Part L for energy efficiency?
• Will the design and installation comply with BS 7671, including correct circuit protection, RCD protection where required, and proper inspection and testing on completion?
• Is the work supported by the appropriate Electrical Installation Certificate or Minor Electrical Installation Works Certificate?

Keeping a clear paper trail — design, risk assessment, certification, and Building Control notification where required — is the simplest way to prove that “reasonable provision” has been made.

How Sparky Safety Can Help

Part P sits within a much wider set of legal duties under the Health and Safety at Work etc. Act 1974, CDM 2015, PUWER 1998, the Electricity at Work Regulations 1989, and reporting obligations under RIDDOR 2013. The Sparky Safety app is built to help you absorb all of this in a way that is genuinely useful on site and in the test centre.

With the app you get:

• Over 300 ECS HS&E practice questions spread across all 11 official topic areas, including general health and safety, electrotechnical, and special site hazards
• 10 BS 7671 calculators covering cable sizing, voltage drop, maximum demand and diversity, earth fault loop impedance, and more — see our maximum demand and diversity calculation guide for a worked example
• Topic-by-topic study guides that explain the legislation behind each question rather than just the answers
• Realistic mock tests at the live ECS format — 45 questions in 45 minutes, with a 38/45 pass mark
• Quick reference guides to BS 7671, building regulations, and the legal framework around domestic electrical work

Whether you are preparing for your ECS HS&E test, brushing up before a domestic installation, or simply making sure your next consumer unit change is properly notified, Sparky Safety gives you the knowledge and confidence to get it right first time.