Electrical installations and Part P compliance

What Part P covers and why it matters

Part P of the Building Regulations sets safety requirements for electrical installations in dwellings. It exists because poor electrical work in homes is a leading cause of domestic fires and electrocution. Part P ensures that electrical work in dwellings is designed, installed, inspected, and tested to a safe standard.

Understanding Part P is important if you own residential property, develop housing, convert buildings to residential use, or carry out any electrical work in a dwelling. Getting it wrong can mean your work is non-compliant, which creates problems when selling or letting a property and can result in enforcement action from building control.

The critical distinction: dwellings versus commercial premises

Part P applies only to dwellings - houses, flats, maisonettes, student accommodation, and the common parts of blocks of flats. It does not apply to commercial premises, industrial buildings, or shops.

Electrical work in commercial and industrial premises is governed by the Electricity at Work Regulations 1989 (EAWR), which impose a general duty to maintain electrical systems in a safe condition but do not require building control notification. If you manage both residential and commercial property, you need to understand which regime applies to each building.

For commercial premises electrical safety, see Electrical safety in your business premises.

Notifiable versus non-notifiable work

Part P divides electrical work in dwellings into two categories. Notifiable work must be reported to building control (either directly or through a competent person scheme). Non-notifiable work must still comply with BS 7671 but does not need building control involvement.

The distinction matters because carrying out notifiable work without proper certification leaves the property without a compliance certificate. This creates difficulties when selling, remortgaging, or letting the property, and can require expensive retrospective regularisation.

Competent person schemes

Competent person schemes provide the most practical route to Part P compliance. Electricians registered with these schemes can self-certify their work, meaning they do not need to involve building control separately. This saves time and money for both the electrician and the property owner.

How the self-certification process works

When a competent person scheme member completes notifiable electrical work:

1. They carry out the work to BS 7671 standards
2. They inspect and test the completed installation
3. They issue an Electrical Installation Certificate (EIC) or Minor Electrical Installation Works Certificate (MEIWC) to the customer
4. The scheme operator notifies the local authority building control within 30 days
5. The customer receives a Building Regulations Compliance Certificate from the scheme operator

This process is seamless for the customer. The key benefit is that you receive the compliance certificate without having to apply to building control yourself or pay a building control inspection fee.

Using a non-registered electrician

If your electrician is not registered with a competent person scheme, you must apply to your local authority building control before work starts for any notifiable work. Building control will arrange inspections during and after the work and charge an inspection fee (typically 200 to 350 pounds). The work must still comply with BS 7671 and the electrician must still provide an EIC or MEIWC.

Using a non-registered electrician is not illegal, but it is more expensive and creates more administrative work. Always check scheme registration before hiring an electrician for domestic work.

BS 7671: the IET Wiring Regulations

All electrical installations in the United Kingdom - whether domestic, commercial, or industrial - must comply with BS 7671 (the IET Wiring Regulations). Currently in its 18th Edition (2018, amended 2022), BS 7671 sets detailed technical standards for the design, erection, inspection, and testing of electrical installations.

BS 7671 is not legislation itself, but it is the standard referenced by Part P and recognised by the courts as representing good practice under EAWR 1989. An installation that does not comply with BS 7671 is very difficult to defend as safe.

Key requirements under the current edition include:

• RCD protection - residual current devices required for most final circuits to protect against electric shock
• Arc Fault Detection Devices (AFDDs) - recommended for certain circuits in dwellings, particularly bedrooms, to detect arc faults that could cause fires
• Surge Protection Devices (SPDs) - required in most new installations to protect against transient overvoltages
• Consumer unit enclosures - must be constructed from non-combustible material in domestic premises

Certificates you should receive

After any electrical work, you should receive the appropriate certificate:

• Electrical Installation Certificate (EIC) - for new circuits, consumer unit replacements, and rewires. Certifies that the new installation has been designed, constructed, inspected, and tested to BS 7671.
• Minor Electrical Installation Works Certificate (MEIWC) - for additions and alterations to existing circuits that do not involve a new circuit. Examples include adding sockets to an existing circuit or replacing a light fitting in a bathroom.
• Building Regulations Compliance Certificate - issued by the competent person scheme operator or local authority building control for notifiable work. This is the document that confirms Part P compliance and is needed for property transactions.

Keep all certificates safely. They are needed when selling or remortgaging the property. If certificates are missing, you may need to apply for retrospective building control regularisation, which typically costs 150 percent of the standard application fee and requires a full inspection of the installation.

How Part P relates to EAWR 1989

Part P and EAWR 1989 serve different purposes and apply to different building types, but they work together to ensure electrical safety across all premises:

• Part P applies to dwellings only and focuses on the installation of electrical work. It requires building control notification for certain work and provides a compliance certification framework.
• EAWR 1989 applies to all workplaces (not dwellings) and focuses on the ongoing safety of electrical systems. It requires systems to be maintained in a safe condition and restricts electrical work to competent persons.

For mixed-use buildings (such as flats above shops), Part P applies to the residential elements and EAWR 1989 applies to the commercial elements. Both require compliance with BS 7671.

If you are converting a commercial building to residential use, the electrical installation must be brought up to current Part P and BS 7671 standards as part of the building regulations approval for the change of use.