How to Check Your Electrician's Work: A Homeowner's Guide

Electrical work is the one area of domestic construction where poor quality doesn't just mean an expensive fix - it means a genuine safety risk. Electrical faults are one of the largest single causes of accidental house fires in England, according to the Home Office and MHCLG fire statistics. Approved Document P of the Building Regulations exists specifically because of this risk, making certain electrical work notifiable (meaning it must be certified or notified to building control). The Approved Documents quoted throughout this guide are the England ones. Wales publishes its own versions, Scotland works to the Technical Handbooks with no Part P equivalent and its own certification of construction schemes, and Northern Ireland has its own Technical Booklets, so check the local regime if you are outside England.

You're not going to test the technical detail yourself unless you're a qualified electrician. That's not what this guide is for. What you can do is check the visible, practical aspects of the installation, make sure you get the right certificates, and know enough to ask the right questions. Before the work starts, make sure you've got the quote right - see our electrician quote breakdown for what to look for. The checks below won't catch a faulty connection inside a junction box, but they'll catch the things that tell you whether your electrician is thorough or cutting corners.

TL;DR Checklist

• Electrician is Part P registered (NICEIC, NAPIT, or BESCA) for notifiable work
• Consumer unit has a metal enclosure and RCD protection on all circuits
• Sockets and switches are 450–1200mm from the floor, consumer unit switches 1350–1450mm
• Supplementary bonding in bathrooms connects all metal pipework to earth
• Cables are in safe zones: vertical from outlets, horizontal near ceiling/floor
• You receive an EIC or Minor Works Certificate plus Building Regs Compliance Certificate
• Outdoor electrics use IP-rated sockets with RCD protection
• Smoke alarms are mains-powered, battery-backed, interlinked, on every storey

The Full Guide

Part P certification

Part P of the Building Regulations controls electrical safety in dwellings. "Notifiable" electrical work is defined by regulation 12(6A) of the Building Regulations 2010 as three things only: installing a new circuit, replacing a consumer unit, and any addition or alteration to an existing circuit in a special location. A special location means the space around a bath tap or shower head, or a room containing a swimming pool or sauna heater. A full rewire counts because it installs new circuits. Ordinary work in kitchens and outdoors stopped being notifiable in its own right when the 2013 edition of Approved Document P took effect, although it is still within the scope of Part P and still has to be safe and compliant. Notifiable work must be certified by an electrician registered with a competent person scheme, by a registered third-party certifier, or by building control.

Competent person schemes such as NICEIC, NAPIT and BESCA cover this. When your electrician is registered with one of these, they can self-certify the work and notify your local authority without a separate building control inspection. They'll issue you a Building Regulations Compliance Certificate as well as the technical test certificates.

Check registration before work starts. Every scheme has an online register where you can search by name or registration number. If the electrician isn't registered, they can still do the work - but you'll need to arrange separate building control inspection and approval, which costs more and takes longer.

Consumer unit

The consumer unit (fuse board) is the heart of your electrical installation. If it's being replaced or newly installed, two things are now mandatory.

First, a metal enclosure. Since January 2016, BS 7671 has required all new or replacement consumer units in domestic properties to have a non-combustible case. In practice, this means metal. Plastic consumer units are no longer permitted for new installations because they can contribute to the spread of fire if a fault develops inside.

Second, RCD protection. All circuits in the consumer unit should be protected by Residual Current Devices - either as RCBOs (combined RCD and circuit breaker in one unit) or as RCDs protecting groups of circuits. An RCD detects current leakage (such as current flowing through a person who's touched a live part) and disconnects the supply in milliseconds.

You can visually check both of these. The consumer unit should be a metal box. Inside, you should see either RCBOs (one per circuit) or a combination of RCDs and MCBs (miniature circuit breakers). Each circuit should be labelled - lights, sockets, cooker, shower, etc. If the labelling is missing or wrong, ask for it to be completed before the electrician leaves.

Socket and switch heights

Approved Document M sets out accessibility requirements for electrical outlets and controls. For new dwellings, Approved Document M Volume 1 puts switches and sockets in the same band: the centre line of switches and socket outlets serving habitable rooms should be 450–1200mm above floor level, and the consumer unit should be mounted so its switches are 1350–1450mm above floor level. The 900–1100mm switch height sometimes quoted comes from Volume 2, which covers buildings other than dwellings. Volume 1 applies to newly erected dwellings and dwellings undergoing material alteration only; paragraph 0.2 confirms it does not apply to the extension of a dwelling.

The logic is accessibility - sockets at skirting level are hard for people with mobility problems to reach, and light switches at head height are difficult for wheelchair users.

For work in existing properties that doesn't trigger Part M compliance, these heights are recommended but not strictly required. However, there's no good reason not to follow them. Sockets at the recommended height are more convenient for everyone, and the work is no more difficult or expensive.

Bathroom bonding

Bathrooms are special locations in electrical terms because of the combination of water and electricity. One specific requirement is supplementary equipotential bonding - connecting all metal pipework (hot water, cold water, central heating, waste pipes if metal) and other metal parts (bath, radiator) to the earth circuit.

This bonding ensures that if a fault develops and a metal pipe becomes live, the current flows safely to earth rather than through anyone touching the pipe. You can usually see the bonding connections - they're typically green-and-yellow-sleeved cables connected to pipes with earthing clamps, often visible under the bath or behind the basin.

Modern plastic plumbing has reduced the need for some bonding (plastic pipes don't conduct), but the requirement still exists where metal is present. Your electrician should assess what bonding is needed based on the actual installation.

Cable routes

This is one you can check during the first fix stage - after cables are run but before the plasterboard goes on. Cables concealed in walls must be in prescribed "safe zones" to prevent someone accidentally drilling into them years later.

The safe zones set out in Regulation 522.6.202 of BS 7671 are: horizontally or vertically in line with an accessory or consumer unit; within 150mm of the top of the wall or partition; and within 150mm of an angle formed by two adjoining walls. A horizontal run at skirting level is not a safe zone, which is why low-level runs need mechanical protection, an earthed metallic covering, or 30mA RCD protection. Cables outside these zones must either be protected by RCD (which they should be anyway from the consumer unit) or enclosed in mechanical protection - typically metal capping or conduit.

Walk the walls during first fix and look at where the cables run. They should follow logical routes: straight up from sockets, straight across near the ceiling. Diagonal runs, cables wandering across the wall at random heights, or cables run across the middle of a wall with no mechanical protection are all non-compliant and potentially dangerous.

Certificates and documentation

At the end of the work, you should receive specific documentation. For notifiable work (new circuits, rewiring, consumer unit changes), you need:

1. Electrical Installation Certificate (EIC) - the technical record of the installation, including test results. For minor additions to existing circuits (adding a socket, moving a light), you'll get a Minor Electrical Installation Works Certificate instead.

2. Building Regulations Compliance Certificate - confirms the work complies with Part P. This is the document that goes on the building control register and the one you'll need when you sell.

The electrical installation certificate should be completed on site, with test results filled in and the electrician's signature and registration details, and handed to whoever ordered the work. The Building Regulations compliance certificate works differently: Approved Document P paragraph 3.4 gives the installer or their registration body 30 days from completion to send you a copy and to notify building control. If nothing has arrived within 30 days, chase the registration scheme directly rather than the electrician.

Outdoor electrics

If your project includes outdoor electrical work - garden lighting, outdoor sockets, electric vehicle charge points, hot tub supply - all circuits must be RCD protected and all equipment must be IP rated (ingress protection against water and particles).

Outdoor sockets should be at least IP66 rated. Connections buried in the ground need to be properly protected in armoured cable or ducting, with adequate depth of cover. The route of any buried cables should be recorded and marked with cable warning tape above the cable at half depth.

Smoke alarms

This is technically a fire safety requirement under Approved Document B rather than Part P, but your electrician will usually install them as part of the electrical work. For new builds, extensions, and loft conversions, the requirements are:

• Mains-powered smoke alarms with battery backup on every storey
• A heat alarm in the kitchen where the specification goes to Category LD2. It is good practice and it avoids the false alarms a smoke detector gives near cooking, but Approved Document B only requires it outright for multi-storey flats using the Approach 4 layout in paragraph 3.21
• All alarms interlinked - so when one goes off, they all go off
• Ceiling mounted and at least 300mm from any wall or light fitting, which is the siting recommendation in BS 5839-6. The 2019 edition of Approved Document B no longer sets siting distances itself, it points to BS 5839-6

Interlinked alarms can be wired together with cable or wirelessly linked with radio frequency. Both are acceptable, but wired is more reliable and is standard for new installations.

Common Problems

No certificates provided after notifiable work. This is the most common compliance failure. The electrician does the work, promises certificates "in the post," and they never arrive. Without an EIC and Building Regulations Compliance Certificate, the work is technically uncertified. Chase immediately - and if they don't produce them, contact their registration body.

Plastic consumer unit on a new installation. Since 2016, this doesn't comply with BS 7671. If your electrician has fitted a plastic consumer unit, ask them to replace it with a metal one. This isn't optional.

Missing labels on the consumer unit. Every circuit should be clearly labelled inside the consumer unit door. "Ring 1," "Lights GF," "Cooker," "Shower," etc. Without labels, isolating a specific circuit for maintenance or in an emergency is guesswork - and guesswork with 230 volts is dangerous.

Smoke alarms that aren't interlinked. Individual battery-powered smoke alarms are not adequate for any work that requires Part B compliance. If you're in the loft bedroom when a fire starts in the kitchen, you need the kitchen heat alarm to trigger the alarm next to your bed. That requires interlinking.

Questions to Ask Your Builder

• "Can I have your NICEIC/NAPIT/BESCA registration number so I can verify it?" - Do this before work starts. It takes 30 seconds online. If they hesitate, find out why.
• "Will you be fitting a metal consumer unit with RCBOs?" - RCBOs give individual RCD protection per circuit, which means a fault on one circuit doesn't trip everything else in the house. It's the better standard.
• "Can you show me the cable routes before the plasterboard goes on?" - A good electrician will be happy to walk you through the first fix. It also gives you a chance to photograph the routes for your records.
• "When will I receive the EIC and Building Regulations Compliance Certificate?" - Ideally on completion, at the latest within a week. Anything longer than that should prompt a follow-up.
• "Are the smoke alarms interlinked, and can you demonstrate them?" - Ask for a test on completion. When one alarm is triggered, every alarm in the house should sound.