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1.1 About This Handbook: Editions and Where It Applies

This guide is written for England. Building Regulations are devolved; Section 4.6 summarises the differences elsewhere, but check your own nation's rules.

The technical content follows the IET Wiring Regulations, BS 7671:2018+A4:2026 (18th Edition, Amendment 4, published 15 April 2026; the previous version is withdrawn on 15 October 2026). BS 7671 is a paid standard, so this guide relies on public summaries from the IET, NICEIC, SELECT, BEAMA and Electrical Safety First.

The legal content follows Approved Document P (Electrical safety, Dwellings), 2013 edition, still the current edition for England. It refers to an older BS 7671 (2008+A1:2011); in practice installers work to the current edition. Nothing here is design guidance: choosing cables and protective devices for new work is a job for a qualified electrician.

1.2 From the Street to Your Consumer Unit

Electricity arrives through a service cable owned by your Distribution Network Operator (DNO), declared at 230 volts, 50 hertz. The Electricity Safety, Quality and Continuity Regulations 2002 allow +10% to −6%, so roughly 216 to 253 volts is normal.

The service cable ends in the cut-out (service head): a sealed box containing the main fuse, which belongs to the network operator and protects their network, not your wiring. From there, short cables run to the meter, which belongs to your supplier or its meter operator. Some homes also have an isolator switch after the meter, which lets an electrician switch everything off without pulling the main fuse.

Meter tails then run to your consumer unit (fuse box). Everything after the meter is yours.

1.3 Supply Earthing: TN-C-S (PME), TN-S and TT

Every installation needs a path to earth so a fault operates a protective device quickly. How you get it depends on the supply.

PME has one specific weakness the IET describes: if the combined neutral-earth conductor breaks on the network (an "open PEN" fault), dangerous voltages can appear on metalwork connected to your main earthing terminal. This is why there are restrictions on using a PME earth outdoors, for example for some EV chargers, and why it must not be used for caravans, boats in marinas and certain other locations.

1.4 Earthing and Bonding Explained

Earthing

Each circuit carries a circuit protective conductor (the earth core) to every metal fitting, socket earth pin and appliance case. If a live conductor touches the metal case of a toaster, current flows along this low-resistance path back to the supply, large enough to trip a breaker or blow a fuse within a fraction of a second. Earthing turns a dangerous fault into a disconnection.

Main protective bonding

Metal pipes entering the house can sit at a different earth potential from your electrical system, so during a fault a person touching a pipe and an appliance could be across a dangerous voltage. Main protective bonding conductors connect gas, water and other incoming metal services to the main earthing terminal so everything rises and falls together. Network guidance puts the gas bond within 600mm of where the pipe enters the property, or inside the meter enclosure, before any branch. Bonding clamps should carry a "Safety Electrical Connection" label. If a plumbing job has left a clamp loose, missing or on a dead-end stub, ask an electrician to check it.

Supplementary bonding

Older bathrooms often have extra cables linking pipes, radiators and baths. BS 7671 allows this supplementary bonding to be omitted only when every circuit in the room has 30mA RCD protection, meets the disconnection requirements, and the pipework is connected to the main bonding. Never remove it yourself; that decision needs testing.

1.5 What Lives Inside the Consumer Unit

A consumer unit divides the supply into final circuits, each with its own protective device. Behind the cover you should never remove are busbars carrying the full supply current. On the front you will see:

• A main switch, usually double-pole, which disconnects line and neutral for the whole installation. Note that it does not make the meter tails or its own incoming terminals dead.
• One or more RCDs (residual current devices), each with a test button marked T, protecting a group of circuits; or individual RCBOs combining an RCD and a circuit breaker for each circuit.
• A row of miniature circuit breakers (MCBs) or, in older boards, fuse carriers.
• Sometimes a surge protective device (SPD), and sometimes arc fault detection devices (AFDDs).

Since 1 January 2016, BS 7671 has required domestic consumer units to have a non-combustible enclosure, such as steel, or to sit in a non-combustible cabinet, after fire investigators reported rising numbers of fires involving plastic units. An older plastic board is not automatically unsafe and need not be replaced, but an inspector may comment on it.

2.1 Ring Final Circuits and Radial Circuits

A ring final circuit (often called a ring main) is a largely British arrangement. The cable visits each socket in turn and returns to the same breaker, so current can reach any socket by two routes and 2.5mm² cable can be protected at 30 or 32 amps. BS 7671's informative Appendix 15 notes that a ring has historically served up to about 100m², and that cookers and hobs over 2kW, immersion heaters and similar heavy, long-duration loads should not be on a ring.

A radial circuit ends at the last socket. The same appendix gives 2.5mm² cable on a 20 amp device (historically up to about 50m²) and 4.0mm² on 30 or 32 amps (about 75m²).

A spur is a branch from a ring or radial. An unfused spur, run in the same cable as the ring, should feed only one single or one twin socket. A fused spur takes its supply through a fused connection unit (FCU) with a fuse of no more than 13 amps, which then protects the cable beyond it.

2.2 Lighting Circuits

Lighting circuits are radials, typically protected by a 6 amp breaker (sometimes 10 amps) and wired in 1.0mm² or 1.5mm² twin-and-earth cable. Most UK houses use the loop-in method: the permanent supply runs from ceiling rose to ceiling rose, and from each rose a separate cable runs down to the switch. That switch cable carries the supply down to the switch and the "switched line" back up to the lamp. In this arrangement there is usually no neutral at the switch, which matters if you want a smart switch (Section 7.7).

A loop-in ceiling rose may hold the incoming supply, the outgoing supply, the switch cable and the lamp flex. In the switch cable, the blue (or older black) core is not a neutral but the switched line, live whenever the light is on; it should be marked with brown or red sleeving. Some houses use junction boxes instead of looped roses, and two-way switching uses three-core cable between switches with terminals marked COM, L1 and L2.

2.3 Fuses and Miniature Circuit Breakers

The basic protective device on each circuit protects the cable against two dangers: overload (too much current for too long, which overheats the cable) and short circuit (a direct line-to-neutral or line-to-earth fault, which produces a very large current).

Older boards use rewireable or cartridge fuses. Rewireable fuses are less precise and easily abused; a carrier rewired with thicker wire gives no protection. Never fit wire above the rating marked on the carrier, and plan for an upgrade.

A miniature circuit breaker (MCB) does the same job with a thermal trip for overloads and a magnetic trip for short circuits. MCBs carry a letter showing how much surge current they tolerate before tripping instantly. Under BS EN 60898, a Type B trips instantaneously at between 3 and 5 times its rated current, a Type C at between 5 and 10 times, and a Type D at between 10 and 20 times. Domestic circuits normally use Type B. A label such as B32 means a Type B breaker rated at 32 amps.

Together with the earth, an MCB disconnects a fault that makes metalwork live. It does not protect a person who touches a live part: a few tens of milliamps through the body can kill, far less than it takes to trip a breaker. That is the RCD's job.

2.4 RCDs and RCBOs

A residual current device compares the current going out along the line conductor with the current coming back along the neutral. In a healthy circuit they are equal. If some current leaks to earth, perhaps through a damaged cable, water in an outdoor fitting or a person, the RCD detects the imbalance and disconnects. An RCD for additional protection against shock has a rated residual operating current of no more than 30mA and must operate within 40 milliseconds at five times that current.

BS 7671 requires 30mA RCD additional protection for, among other things:

• socket outlets rated up to 32 amps (with narrow, documented exceptions outside dwellings);
• mobile equipment rated up to 32 amps for use outdoors;
• final circuits supplying luminaires (light fittings) in domestic premises;
• cables concealed in walls or partitions at less than 50mm deep, unless they have earthed metallic protection (see Chapter 8);
• every circuit serving a room containing a bath or shower.

RCD types (AC, A, F, B) differ in the leakage they detect. The IET warns that electronic equipment can produce leakage that "blinds" a Type AC device, so choosing the type is a design decision for the electrician. On a split-load board one fault trips every circuit on that RCD; an RCBO combines RCD and MCB for a single circuit, so a fault only switches off that circuit.

2.5 AFDDs and SPDs

An arc fault detection device (AFDD) watches for the signature of arcing at a loose terminal or damaged cable, which can start a fire without tripping an MCB or RCD. Since BS 7671 Amendment 2 (2022), AFDDs have been required for socket circuits rated up to 32 amps in higher-risk residential buildings, houses in multiple occupation, purpose-built student accommodation and care homes, and they are recommended for such circuits elsewhere. They are not required retrospectively in an existing house.

A surge protective device (SPD) diverts brief high-voltage transients, such as those from lightning on the network. BS 7671 requires this protection in a single dwelling unless the value of the installation and its equipment does not justify it; the IET notes that an SPD costs little compared with replacing damaged equipment.

2.6 Cable Colours and Cable Sizes

The 2004 to 2006 colour change

The harmonised colours could be used from 31 March 2004; during a two-year transition either set could be used (but not both in one alteration), and only the new colours have been permitted since 31 March 2006. Appliance flexes had used brown, blue and green-and-yellow since 1969.

Beware: black is a neutral in old wiring but a line conductor in new three-core cable. A mixed installation needs a warning notice at the consumer unit. Approved Document P notes that old-colour cables need not be replaced simply because of their colour, if otherwise adequate.

Older cables

If you find rubber insulation, a cloth or lead sheath, or insulation that crumbles, do not disturb it; have the installation inspected. Some older lighting circuits have no earth conductor at all, and a metal fitting or switch plate must not be fitted there (Section 7.4).

Typical cable sizes (for recognition only)

The table is for recognition only; sizing a new circuit is a calculation for the electrician.

Avoid burying cables in thermal insulation, which stops them shedding heat. When adding loft insulation, keep cables on top where you can.

3.1 Identifying What Is in Front of You

Open the hinged flap (never the screwed cover) and read each device's markings:

• Main switch: usually the largest, marked with a rating such as 100A.
• RCDs: wider than an MCB, with a T or Test button and a marking such as "30mA" or "IΔn 0.03A".
• MCBs: narrow single-module switches marked with a letter and number, such as B6 or B32.
• RCBOs: like an MCB but with a test button and 30mA marking.
• SPD (status window) and AFDD (test button, sometimes indicator lights).

3.2 Labelling Your Circuits

Approved Document P expects permanent labels so people can operate an installation safely, yet many boards are wrongly labelled. An accurate circuit chart needs only a notepad and a plug-in lamp.

1. Choose a daytime slot, warn the household, and note clocks, timers and the boiler programmer that will need resetting.
2. Number the devices from left to right.
3. Switch off one MCB or RCBO and record every light, socket (both outlets of each double) and fixed appliance that stops. Switch it back on and repeat.
4. Keep the chart by the board, label the strip, and note oddities such as a socket on a lighting circuit.

3.3 Testing Your RCDs

The test button checks that the RCD's mechanism works. BS 7671 calls for a notice at the board asking the user to press it; the IET explains that the recommended interval changed from quarterly to six-monthly in the 18th Edition, and suggests doing it when the clocks change.

1. Warn the household, then press the T button. The RCD should switch off at once.
2. Switch it back on. If it will not reset, see Section 3.5.

If it does not trip, it is faulty and those circuits have lost shock protection: call an electrician promptly. The button only tests the mechanism, not the trip time.

3.4 What a Trip Is Telling You

3.5 Finding the Cause of a Trip, Step by Step

If an RCD has tripped

1. Unplug appliances on the affected circuits, especially kettles, washing machines, dishwashers, ovens, immersion heaters and outdoor equipment.
2. Switch off every MCB protected by that RCD.
3. Reset the RCD. If it will not stay on with every MCB under it switched off, stop: the fault is in the board or the wiring near it. Call an electrician.
4. Switch the MCBs back on one at a time. If the RCD trips when a particular MCB goes on, that circuit has the fault. Leave it off and restore the others.
5. With all appliances on that circuit still unplugged, try that MCB once more. If the RCD now holds, the fault is in an appliance. Plug the appliances in one by one, switching each on, until the trip recurs. Take that appliance out of use.
6. If the RCD trips on that circuit with every appliance unplugged and every fixed appliance switched off at its FCU or isolator, the fault is in the fixed wiring or a fixed appliance. Leave the circuit off and call an electrician.

If an MCB has tripped

1. Switch off and unplug what was in use on that circuit, and think about what was switched on just before the trip.
2. Reset the MCB once. If it holds, reconnect appliances one at a time, spreading heavy loads across circuits.
3. If it trips immediately with everything on that circuit unplugged, there is a fault in the wiring. Leave it off.

3.6 When to Stop

If water reaches the consumer unit or any fitting, touch nothing wet. Switch off the main switch only if you can do so dry and safely; otherwise keep everyone away and call an electrician, or 105 if the supply equipment is affected.

4.1 What Part P Requires

Part P of Schedule 1 to the Building Regulations 2010 came into force (in its original form) on 1 January 2005. Its single requirement, P1, reads: "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."

It covers installations in or attached to a dwelling, the common parts of flats, and gardens and outbuildings supplied from the dwelling. Two points are often misunderstood:

• All work must meet P1. Approved Document P says non-notifiable work should still be designed, installed, inspected, tested and certificated to BS 7671, and councils can take enforcement action against unsafe work.
• "Not notifiable" only means you need not tell building control.

4.2 Notifiable and Non-Notifiable Work in England

Since 6 April 2013, regulation 12(6A) of the Building Regulations 2010 makes work notifiable where it consists of:

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

A special location is defined in the regulations as either a room containing a swimming pool or sauna heater, or, within a room containing a bath or shower, the space around the bath tap or shower head. That space extends from the floor up to 2.25 metres (or to the shower head, if it is fixed higher), and horizontally 0.6 metres from the edge of the bath or shower tray; where there is no tray, 1.2 metres from the centre of the shower head.

All other work is not notifiable, "namely additions and alterations to existing installations outside special locations, and replacements, repairs and maintenance anywhere". Approved Document P's examples: a built-in cooker is not notifiable unless a new cooker circuit is needed; connecting a garage door to an existing isolator is not, but a new circuit to that isolator is.

4.3 The Three Routes to Compliance

1. Self-certification by a registered competent person. A registered electrician does the work, issues an Electrical Installation Certificate and notifies it; within 30 days the scheme sends you a Building Regulations compliance certificate and informs building control. This is the usual route.
2. Third-party certification. An unregistered installer appoints a registered certifier before work begins and notifies them within 5 days of finishing; if testing is satisfactory, the certifier's scheme issues the certificate.
3. Building control. The installer, who may be a homeowner, notifies a building control body before work begins and pays a fee; if satisfied, it issues a completion or final certificate.

The schemes authorised for domestic electrical work are listed on GOV.UK; at the time of writing they are BESCA, Blue Flame Certification, Certsure (which operates the NICEIC and ELECSA brands), NAPIT and OFTEC. The joint register at electricalcompetentperson.co.uk lets you look up registered electricians across schemes.

4.4 Certificates You Should Receive

For notifiable work you should receive both the BS 7671 certificate and the compliance certificate; keep them with the deeds. Owner-occupiers have no legal duty to commission inspections, but inspection at least every 10 years and on moving in is widely recommended.

4.5 If Work Was Done Without Notification

Contravening the Building Regulations is an offence under section 35 of the Building Act 1984 (as substituted by the Building Safety Act 2022), punishable by a fine and, on indictment, up to two years' imprisonment. More often the consequence is a problem when selling.

For unnotified work carried out after 11 November 1985, the owner can apply to the local authority for a regularisation certificate. The authority must be satisfied the work complied with the regulations at the time, which usually means paying for inspection and testing and putting faults right.

4.6 Wales, Scotland and Northern Ireland

• Wales has its own Approved Document P. The 2013 changes that narrowed notifiable work in England were not made in Wales, so a wider range of work is notifiable there, including some work in kitchens and outdoors (for example garden lighting and supplies to outbuildings). Check the Welsh Government's guidance before starting anything.
• Scotland uses a separate building standards system with building warrants and its own technical handbooks, rather than Part P. Ask your local authority building standards service what applies.
• Northern Ireland also has its own building regulations regime. Check with your council's building control service.

BS 7671 is the recognised standard across the UK, so the technical guidance here still applies.

4.7 Buying and Selling a House

The Law Society's TA6 property information form, used in England and Wales, asks sellers about building works and their certificates, and buyers' conveyancers will look for compliance certificates for notifiable electrical work. Missing paperwork can be resolved by asking the installer or scheme for copies, regularisation, or an indemnity policy. When buying, an EICR before exchange is worthwhile; rewireable fuses, no RCDs, mixed colours without a notice, or rubber-insulated cables all suggest work is needed.

5.1 Landlords: The Electrical Safety Standards Regulations

The Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020, extended to social housing in 2025, apply where a tenant pays rent and occupies the home as their main residence. According to GOV.UK guidance (November 2025), landlords must:

• ensure the standards in BS 7671 are met while the home is let;
• have the electrical installation inspected and tested by a qualified person at least every 5 years, and obtain a report (usually an EICR) giving the results and the date of the next inspection;
• give a copy of the report to the existing tenant within 28 days of the inspection, to a new tenant before they occupy, and to a prospective tenant within 28 days of a request;
• give a copy to the local council within 7 days of a request;
• where the report requires remedial or further investigative work, complete it within 28 days (or sooner if the report says so), then give the tenant and the council written confirmation from the qualified person within 28 days of completion.

Councils can impose a financial penalty of up to £40,000 for breaches. Exclusions include lodgers sharing with the landlord, leases of 7 years or more, student halls, hostels, refuges and care homes. A new or fully rewired home with an EIC needs no further report until 5 years after it was issued.

Social landlords must also check equipment they supply at least every 5 years; for existing social tenancies, first inspections are due before 1 November 2026.

5.2 Reading an EICR

The GOV.UK guidance defines the codes as follows.

An "unsatisfactory" report means specific defects need fixing, not necessarily a rewire. Ask the inspector to explain each item, and get remedial quotes against the same list.

5.3 Smoke and Carbon Monoxide Alarms in Rented Homes

Under the Smoke and Carbon Monoxide Alarm (England) Regulations 2015, as amended in 2022, from 1 October 2022 all relevant private and social landlords in England must:

1. ensure at least one smoke alarm is fitted on each storey of the home where there is a room used as living accommodation;
2. ensure a carbon monoxide alarm is fitted in any room used as living accommodation that contains a fixed combustion appliance, excluding gas cookers;
3. repair or replace alarms once told they are faulty.

Alarms must be checked on the first day of a new tenancy, and councils can impose a penalty of up to £5,000 for failing to comply with a remedial notice. The government recommends alarms to BS 5839-6 (smoke) and BS EN 50291 (carbon monoxide), preferably with sealed-for-life batteries, and suggests smoke alarms on the ceiling of a hall or landing and carbon monoxide alarms at head height about 1–3 metres from the appliance. Heat alarms do not replace smoke alarms. These rules do not apply to owner-occupiers.

5.4 Alarms in New Homes and Building Work

For new dwellings and certain material alterations in England, Approved Document B (Volume 1, 2019 edition as amended) says:

• all dwellings should have a fire detection and alarm system to a minimum of Grade D2 Category LD3 under BS 5839-6, which in practice means mains-powered smoke alarms with a standby supply in the circulation spaces of each storey;
• smoke alarms should be mains operated and conform to BS EN 14604; heat alarms should be mains operated and conform to BS 5446-2; both should have a standby power supply such as a battery;
• larger houses need a higher grade: a house of more than one storey in which any storey exceeds 200m² needs a Grade A system;
• a fire detection and alarm system should be installed when a new habitable room is provided above or below the ground storey (for example a loft conversion), or at ground level without a final exit.

Approved Document J (2022 amendments) says a new or replacement fixed combustion appliance (other than one used solely for cooking) should have a carbon monoxide alarm to BS EN 50291-1 in the same room, battery-powered for its working life or a fixed-wired Type A alarm, mounted on the ceiling at least 300mm from a wall (or high on a wall but not within 150mm of the ceiling) and 1–3 metres horizontally from the appliance.

Battery alarms need no electrical work. Mains alarms are installation work (notifiable if on a new circuit) with their own design rules in BS 5839-6: use an electrician.

5.5 Good Practice for Owner-Occupiers

• Test smoke and carbon monoxide alarms monthly using the test button, and replace them at the end of the life the manufacturer states (often printed on the alarm).
• Press the RCD test buttons every six months (Section 3.3).
• Have the installation inspected when you move in and at least every 10 years, or sooner if the inspector recommends it.
• Look round once a year for scorched accessories, warm plugs and damaged flexes.

6.1 Why Switching Off Is Not Enough

The classic DIY accident follows a belief that a circuit was off: the label was wrong, the rose was live from the loop, a neighbouring circuit shared the box, or someone switched the breaker back on. Electrical Safety First's Best Practice Guide 2 puts it plainly: never assume equipment is dead because an isolating device is in the off position.

Safe isolation means: isolate the right circuit, secure it so nobody can reverse it, and prove dead with a tester proved before and after. Every time.

6.2 The Equipment: What GS38 Asks For

The HSE's GS38 (fourth edition, 2015) is written for workplaces but is the recognised reference for safe test equipment.

A two-pole voltage indicator

GS38 recommends a proprietary test lamp or a two-pole voltage detector (to BS EN 61243-3), which indicates voltage by two or more independent means and limits its current. Probes should:

• have finger barriers or be shaped to keep fingers away from the metal;
• be insulated to leave an exposed tip of no more than 4mm (GS38 strongly recommends 2mm or less, or spring-loaded retractable shrouded probes);
• be marked with a measurement category (CAT II, III or IV) and a voltage rating suitable for where they will be used. Measurements in the building installation, such as at sockets and distribution boards, fall into category III.

A proving unit

Testers can fail silently, so GS38 says they should be proved before and after use, preferably on a voltage proving unit (a battery box that generates a test voltage). Branded indicator and proving unit kits cost roughly £130 to £250 including VAT at 2026 retail prices.

Other kit

• Insulated screwdrivers (1000V, BS EN 60900): not a licence to work live.
• A breaker lock-off and padlock, or at least tape and a warning label.
• A head torch, as the lights may be off.

6.3 Why Not a Neon Screwdriver, a Voltage Stick or a Multimeter?

A non-contact indicator is a useful extra warning, but as Electrical Safety First says, a cable it does not show as live must not be assumed dead on that basis alone.

6.4 The Safe Isolation Procedure, Step by Step

6.5 Hidden Hazards That Catch People Out

• Borrowed neutrals. Electrical Safety First warns that using the neutral of one circuit for another is not permitted by BS 7671 but is common, especially on lighting. A borrowed neutral can become live when you disconnect it, even though its own circuit is off. This is why step 5 tests neutral to earth.
• Two-way and multi-circuit switches. A switch plate may carry conductors from more than one circuit. Test every conductor in the box.
• Automatic and remote controls. Timers, photocells, smart plugs and app-controlled devices can switch a load on unexpectedly. Isolate at the consumer unit, not at the control.
• Solar panels and batteries. An installation with solar photovoltaic panels, battery storage or a generator has more than one source of supply. Battery systems with an "island mode" may keep circuits live when the grid supply is off. Do not work on such an installation unless you know how every source is isolated; if in doubt, leave it to an electrician.
• Stored energy. Some equipment containing capacitors can hold a charge for a short time after isolation. Follow the manufacturer's instructions.

Without a proper voltage indicator and proving unit, you are not equipped to remove a faceplate, and Chapter 7 is not for you.

7.1 Before You Start: The Ground Rules

The jobs here are replacements: a similar accessory in the same place on the same cables. They are not notifiable in England, but must still meet BS 7671. Before any job:

• Read the procedure and the product's instructions.
• Buy UKCA or CE marked accessories made to the relevant British Standard (BS 1363 for sockets and plugs) from an established retailer.
• Photograph the wiring before disconnecting anything, and label conductors if in doubt.
• Carry out the full safe isolation procedure (Section 6.4); every job assumes it.

Making a good termination

• Strip just enough insulation for the conductor to enter the terminal fully, with no bare copper showing and no insulation under the screw.
• Where two or three conductors share a terminal, twist them together so all are gripped.
• Tighten firmly (to the maker's torque if given): loose terminals cause scorched sockets.
• Sleeve bare earth conductors green-and-yellow, and fold cables back without crushing them.

7.2 Replacing a Socket Faceplate Like for Like

1. Isolate and lock off the circuit (Section 6.4). On a ring, every socket on that ring is now off.
2. Undo the faceplate screws and ease the plate forward. Prove dead between every pair of conductors for every cable, then re-prove your tester.
3. Photograph the wiring. One cable usually means a radial end or spur; two, a ring or a radial passing through; three, a ring with a spur.
4. Remove the conductors. Cut back and re-strip any damaged ends if there is enough length; if not, stop.
5. Connect the new faceplate: all browns (or reds) into L, all blues (or blacks) into N, all green-and-yellow into E. If the back box is metal and has its own earth terminal, connect a short green-and-yellow earth lead from that terminal to the faceplate's earth terminal.
6. Tug each conductor gently, fold the cables in, and tighten the plate evenly.
7. Restore the circuit and check every socket on it works. A plug-in socket tester is a useful extra check at the new socket.

A socket with USB outlets is a fine replacement if it meets the standards and fits the existing back box.

7.3 Replacing a Light Switch Like for Like

1. Isolate and lock off the lighting circuit at the consumer unit. Turning the switch off is not isolation.
2. Remove the plate and prove dead on every conductor; a box may hold more than one circuit.
3. Photograph the terminals (COM and L1 on a one-way switch; COM, L1 and L2 on a two-way) and move each conductor to the identical terminal on the new switch. Sleeve the blue or black switched line brown or red.
4. If the new plate is metal, it must be earthed: connect the circuit's earth conductor to the plate's earth terminal. If there is no earth conductor in the box, do not fit a metal plate. Fit a plastic one.
5. Refit, restore power and check the light switches correctly from every switch that controls it.

With LED lamps, a dimmer must be compatible with the lamps and within its minimum and maximum load; otherwise it flickers, buzzes or fails early.

7.4 Replacing a Light Fitting Like for Like

1. Check the new fitting's weight, fixing, class and, for bathrooms or outdoors, IP rating (Chapter 9).
2. Isolate and lock off the lighting circuit. Use a stable platform and a torch.
3. Remove the rose cover and prove dead on every conductor, including the loop terminals, which may be fed from elsewhere.
4. Photograph and label the groups: the loop line (several browns or reds together: supply in, supply out and feed to the switch); the neutrals; the switched line back from the switch (blue or black, sleeved brown or red); and the earths.
5. Reconnect each group to the new fitting's terminal block, or to suitable enclosed connectors such as lever connectors to BS EN 60998: the loop line group on its own; neutrals with the lamp neutral; the switched line to the lamp line; earths with the fitting's earth.
6. Fix the fitting securely; a heavy fitting needs a joist or proper support, not plasterboard plugs. Check no conductor is trapped and fit the canopy.
7. Restore power and check this light and the others on the circuit. If another light has stopped working, the loop is mis-connected: isolate and recheck.

7.5 Wiring a Plug and Choosing the Right Fuse

Leave moulded plugs alone where you can. If you must fit one, use a BS 1363 plug and a BS 1362 fuse.

1. Strip the outer sheath so the cord grip will clamp the sheath, not the inner cores.
2. Cut the cores to length: green-and-yellow to E (top), brown to L (beside the fuse), blue to N. Leave the earth slightly longer so it is the last to pull free.
3. Strip, twist the strands, insert fully and tighten, with no stray strands. Tighten the cord grip, fit the right fuse and close the plug.

Choosing the fuse

The plug fuse protects the flex. Fire and rescue services advise a 3 amp (red) fuse for appliances up to about 700 watts and a 13 amp (brown) fuse from about 700 to 3,000 watts, unless the manufacturer specifies otherwise. Divide watts by 230 to check: a 2,000W heater draws about 8.7A (13A fuse); a 60W lamp about 0.26A (3A fuse). If a fuse blows, find out why, then replace it with the same rating, never higher, and never foil or wire.

7.6 Replacing a Fused Connection Unit Faceplate

A fused connection unit (FCU) supplies a fixed appliance or a spur. Its terminals are marked SUPPLY and LOAD; reversing them leaves the fuse protecting the wrong side.

1. Isolate the circuit at the consumer unit (not just at the FCU) and prove dead on all conductors.
2. Photograph which cables are on the supply side (two if on a ring) and which on the load side, and transfer each to the matching terminal of the new FCU, with all earths to the earth terminal.
3. Fit a fuse of the same rating as before, or the rating the appliance maker specifies.
4. Refit, restore and test the appliance.

If the FCU is within the zone around a bath or shower, the replacement must suit that zone. Mains switches, including switched FCUs, are not permitted in zones 1 or 2 unless they form part of a SELV circuit (Chapter 9).

7.7 Smart Switches

A smart switch in place of an ordinary one is a replacement and not notifiable. Three issues decide whether it will work.

• Neutral. Loop-in wiring usually leaves no neutral at the switch, and many smart switches need one. "No-neutral" models pass a small current through the lamp, which can make LEDs flicker or glow, sometimes cured by the maker's bypass device. Running a new cable for a neutral is an alteration: use an electrician.
• Depth. Check the switch body against your back box.
• Compatibility. Check load limits, lamp types and two-way support.

Remember Section 6.5: a smart switch can turn a light on remotely. Always isolate at the consumer unit before working on smart lighting.

7.8 Outdoor Sockets

Adding an outdoor socket off an existing indoor circuit is not notifiable in England unless a new circuit is needed (it may be in Wales). It is still not a beginner's job:

• It needs 30mA RCD protection, which the existing circuit may lack.
• It needs a suitable weatherproof IP rating, a protected cable route through the wall, and safe-zone routing inside.
• A wrongly extended ring can overload its cable, and the circuit must be tested with instruments afterwards.
• On PME supplies, outdoor work raises the earthing issues in Section 1.3.

Use a registered electrician and expect a Minor Works certificate (or an EIC for a new circuit). Replacing a damaged outdoor socket with a correctly rated weatherproof unit is a replacement; follow Section 7.2 and reseal the enclosure.

7.9 Jobs for a Registered Electrician

8.1 The Safe Zones in BS 7671

BS 7671 restricts where cables buried less than 50mm deep in a wall may run. The IET's summary of Regulation Group 522.6 describes these safe zones:

• within 150mm of the top of the wall or partition (that is, just below the ceiling);
• within 150mm of an angle formed by two adjoining walls (the corners);
• running horizontally or vertically in line with a point, accessory or switchgear that the cable connects to, such as a socket, switch or fused spur, on any surface of the wall.

BS 7671 also requires cables concealed at less than 50mm in a wall or partition to have 30mA RCD protection (since Amendment 3 of 2015 this applies to every type of installation, not just homes), unless they have an earthed metal covering or are enclosed in earthed metal conduit or trunking, or form part of a SELV or PELV circuit. The same applies at any depth in a partition built with metal parts other than fixings, such as a metal-stud wall.

8.2 Reading a Wall Before You Drill

Use the zones as a map of where cables are likely, then look for clues:

• Every accessory implies a cable running up, down or sideways from it, including thermostats, wall lights and fans.
• Check the other side of the wall: on a stud partition, zones extend straight through.
• Kitchen walls often hide cables to cooker switches and appliance spurs.
• Older or amateur work may ignore the zones entirely.

Cable detectors help but can miss deep or screened cables and be fooled by foil-backed board or damp plaster. Believe the more cautious answer.

8.3 Drilling and Fixing Safely

1. Decide whether the fixing can go somewhere clearly outside every zone; a few centimetres sideways often solves the problem.
2. Check both sides of the wall and scan with a detector.
3. Where a fixing must go near a zone, consider switching off and locking off the circuits that could be in that wall while you drill. This will not prevent damage to a cable, but it removes the shock risk at the moment of drilling.
4. Use a drill stop or tape on the bit so you drill no deeper than the fixing needs. Shallow cables are the ones at risk.
5. Drill slowly; stop if the drill suddenly breaks through or the dust changes colour (copper swarf, or plastic shavings).
6. Afterwards, check that the circuits you switched off come back on and that no RCD trips.

8.4 Floors, Ceilings and Lofts

BS 7671 requires cables under floors and above ceilings to be run where they will not be damaged by the floor, the ceiling or their fixings. Where a cable passes through a timber joist or batten, it should be at least 50mm from the top or bottom edge, unless it has earthed metal protection. Cables are therefore often found clipped along the sides of joists or passing through holes drilled near their centre.

• Before screwing down floorboards, lift a board to see where cables cross, and keep screws away from the lines of any holes or notches in the joists. Choose screws only as long as needed.
• In the loft, do not stand on or crush cables, and do not bury them in insulation where you can avoid it (Section 2.6). Downlighter fittings can get hot; follow the maker's guidance on clearances and insulation covers.
• Old cables lying loose in a loft that end in nothing are not necessarily dead. Do not cut them; have them identified.

9.1 Why Bathrooms Are Different

Wet skin greatly reduces the body's resistance, and bathers touch earthed taps and pipes. BS 7671 Section 701 therefore sets zones and rules for rooms with a bath or shower. The details below follow SELECT's summary of the A2:2022 text; your electrician will work from the current standard.

9.2 The Zones

• Zone 0 is the inside of the bath tub or shower tray. For a shower without a tray, zone 0 is 0.10m high and has the same horizontal extent as zone 1.
• Zone 1 is the space above the bath or shower tray, up to 2.25m from the floor or the height of the highest fixed shower head, whichever is higher. The space under the bath is zone 1 if it can be reached without a tool. For a shower without a tray, zone 1 extends 1.20m horizontally from the centre of the fixed water outlet.
• Zone 2 extends 0.6m horizontally beyond zone 1, to the same height. A shower without a tray has no zone 2; its zone 1 is enlarged instead.
• Everything else in the room is outside the zones, but still within the special location, so the RCD rules below still apply.

9.3 IP Ratings

The IP code (BS EN 60529) rates solids (first digit, 0–6) and water (second digit, 0–8); X means not rated.

IP44 means protected against objects over 1mm and splashing; IP65, dust-tight and protected against jets. Always check the product is stated to suit its zone.

9.4 What May Go Where

Approved Document P's 2013 diagram says 3m from the bath or tray, reflecting the BS 7671 of its day; the 18th Edition figure is 2.5m from the zone 1 boundary. Every circuit serving the room, or passing through zones 1 or 2, needs 30mA RCD protection.

Ceiling pull-cord switches, which are operated by an insulating cord, are commonly used to control bathroom lights from inside the room. Like everything else, their position must suit the zones; ordinary wall switches are usually placed outside the room.

9.5 Shaver Sockets

The only mains socket permitted in zone 2 is a shaver supply unit to BS EN 61558-2-5. Its isolating transformer means touching one pin and earthed metal does not give a shock through that path. It is for shavers and toothbrushes only, never hair dryers via adaptors, and must be sited away from direct spray. "Shaver sockets" without an isolating transformer are not suitable for bathrooms.

9.6 Extractor Fans

Approved Document F (2026 edition, Volume 1: Dwellings) gives a minimum intermittent extract rate of 15 litres per second for a bathroom where an intermittent fan is used. In a room with no openable window, the fan should have controls that keep it running for at least 15 minutes after the room is vacated, and any automatic control such as a humidistat should have a manual override. Extract fans and terminals should be as high as practicable and no more than 400mm below the ceiling.

A fan in zone 1 must be at least IPX4 and suitable for the zone; some are SELV models with a transformer outside the zones.

• Replacing a failed fan with a similar one on the same wiring is a replacement and not notifiable, but the new fan must suit the zone it is in.
• Adding or moving a fan is an addition, notifiable if within the special location. Use an electrician.

9.7 Electric Bidet Toilet Seats

An electric bidet seat, often called a Japanese toilet seat or by TOTO's trade name Washlet, replaces an ordinary toilet seat. It has a heated seat, a warm-water wash wand and often a warm-air dryer, and it needs two connections: mains electricity and a cold water feed taken from the cistern supply. The job splits cleanly. An electrician provides the power point; you can fit the seat and connect the water, following the maker's instructions.

Choosing a Seat

• Buy a model sold for the UK, rated 220–240V. Seats made for the Japanese home market run on 100V and are not for a UK bathroom.
• Check the seat fits your pan. Makers publish the pan length and fixing-hole spacing they suit, and some pans (rimless, back-to-wall or with a concealed cistern) need a specific model. Measure before you order.
• Check the backflow protection (see below). Look for WRAS approval or the maker's written statement that the seat meets the UK water fittings regulations.

The Electrical Supply

These seats are Class I appliances: they must be earthed. TOTO's installation guide, for example, requires a supply protected by a 30mA RCD (which every circuit serving a bathroom needs anyway), asks for an easily reached connection, rates its seat at 269–315W, and supplies a power cord only about 1m long. In the UK the difficulty is the socket. BS 7671 forbids ordinary socket outlets within 2.5m horizontally of the boundary of zone 1 (Section 9.4), and in most British bathrooms the toilet is well inside that distance, so plugging in beside the pan is usually not allowed.

The usual answer is for an electrician to fit a fused connection unit (FCU) fed from an existing circuit, outside the zones and within reach of the seat's cord, either with a flex outlet or with the seat's flex wired directly into it. A fused connection unit is not a socket outlet. Where the toilet really is more than 2.5m from the edge of zone 1, a socket outlet can be used. Either way, the electrician chooses the fuse rating the maker specifies and checks RCD protection.

• Notification: a spur outside the special location (more than 0.6m from the bath or shower tray, or 1.2m from the shower head where there is no tray) is an addition outside a special location and is not notifiable in England. Inside that space, it is notifiable (Section 4.2). Either way, it is a job for an electrician, not a homeowner.
• Removing the plug: if the seat comes with a moulded plug, ask the maker before having it cut off for a fused connection unit, as some warranties depend on the supply arrangement.

The Water Supply and Backflow

A wash wand sits inside the toilet pan, and water from the pan must never be able to siphon back into the drinking water supply. Water Regs UK classes a combined toilet and bidet as a fluid category 5 risk, the highest category. The seat must therefore have built-in category 5 backflow protection that meets UK requirements. Otherwise it must be supplied through a break tank with a Type AB air gap, which is impractical for a seat. In practice, buy a seat whose protection is confirmed for the UK.

Tell your water supplier first. The Water Supply (Water Fittings) Regulations 1999 list "a bidet with an ascending spray or flexible hose" among the fittings that need advance notice to the water supplier, who then has ten working days to respond. Water Regs UK says installing a combined toilet and bidet is notifiable in Scotland and Northern Ireland and could be notifiable in England and Wales. Contact your water supplier, say which seat you plan to fit, and follow any conditions it sets.

Connect the seat to the cold supply only. TOTO warns that a hot feed can cause burns or damage, because the seat heats its own water. Its guide also gives an operating pressure range of 0.1–1.0 MPa (1–10 bar); check your seat's figures if your mains pressure is unusually high or low.

Procedure: Fitting the Seat

You need: the seat and the parts supplied with it (usually a base plate, a T-adaptor or tee valve and a new hose), an adjustable spanner, a screwdriver, a towel and a bowl. Before you start: the electrician's supply point should be in place but switched off, and you should have told your water supplier.

1. Isolate the water. Close the isolating valve on the cistern feed (a quarter turn with a flat screwdriver on most) and flush to empty the cistern. If there is no isolating valve, have one fitted first: you will need it to service the seat.
2. Remove the old seat by undoing the nuts under the back of the pan. Clean the pan rim and fixing holes.
3. Fit the base plate to the pan with the supplied bolts, centred and square, at the position the instructions give. Do not overtighten on ceramic.
4. Fit the tee. Disconnect the cistern's flexible connector at the isolating valve, fit the supplied T-adaptor, and reconnect the cistern to one outlet. Use the new hose supplied with the seat for the other outlet; TOTO, for one, says never reuse an old hose.
5. Slide the seat onto the base plate until it clicks, then pull gently towards you to check it is locked. Never lift the unit by the seat or lid.
6. Connect the hose to the seat's water inlet without kinking or crushing it. Hand-tighten, then nip up only as far as the instructions allow.
7. Open the isolating valve slowly and check every joint for drips with dry tissue. Let the cistern refill and flush once.
8. Switch on the supply only now, with the water connected. Run the seat's first-use or air-purge routine, then test each function. Some seats have a seat sensor that must detect someone sitting before the wand will run.
9. Check again the next day for slow leaks under the tee and at the seat inlet.

10.1 Kitchens

A kitchen is not a special location, and in England adding a kitchen socket to an existing circuit is not notifiable (it may be in Wales). But kitchens combine heavy loads, water and many appliances.

• Heavy loads. Several kitchen appliances together can approach a ring's limit, and cookers and hobs over 2kW belong on their own radial.
• Built-in appliances are often isolated by labelled switches above the worktop. Keep them labelled.
• Water and heat. Keep sockets and switches away from splashing and from reaching across a hob.
• Plug-in modular lighting is within the scope of Part P, but notifiable only if it involves regulation 12(6A) work.

10.2 Cookers and Hobs

A cooker or hob is usually on its own circuit with a nearby cooker control unit or double-pole switch. Installing one is not notifiable unless a new circuit is needed.

• A similar cooker on the existing circuit and outlet is a replacement; a more powerful one may need the circuit checked.
• Switching from gas to electric usually needs a new, notifiable circuit; gas work is for a Gas Safe registered engineer.
• Some small ovens and hobs may use a 13 amp plug or fused spur, but only where their instructions say so.

10.3 Electric Showers and Immersion Heaters

An electric shower heats water instantly, which takes a great deal of power: models of 8.5kW to 10.5kW are common, and a 10.5kW shower draws over 45 amps at 230 volts. Shower manufacturers' instructions typically call for a dedicated circuit from the consumer unit, sized by calculation, with a suitably rated double-pole isolating switch positioned outside the zones, and BS 7671 requires 30mA RCD protection for every circuit serving the bathroom. A new electric shower is notifiable (new circuit and work in a special location). Replacing a shower like for like, with the same or lower rating on the existing circuit, is a replacement, but the electrical connections are inside zone 1 and the new unit's rating must be checked against the existing circuit and cable. If the new unit is more powerful, the circuit may need upgrading.

A discoloured or buzzing shower switch, repeated trips or a hot-plastic smell mean stop and call an electrician. Immersion heaters, also heavy long-duration loads, belong on their own circuit, not a ring.

10.4 Outdoor and Garden Electrics

Part P covers fixed installations in gardens and outbuildings supplied from the house. Outdoor work combines water, mechanical damage, buried cables and, on PME, the earthing issues in Section 1.3.

• A supply to an outbuilding is normally a new, notifiable circuit needing suitable buried cable and earthing decisions.
• Extra-low voltage garden lighting reduces shock risk, but its mains transformer connection is installation work.
• Use mowers and trimmers from an RCD-protected socket, or a plug-in RCD adaptor tested before use.
• Never power a shed through a permanent extension lead out of a window.

10.5 Electric Vehicle Chargers

A home EV charge point is almost always on a new dedicated circuit and is therefore notifiable work. It is also specialist work, for several reasons:

• Hours of high current mean the supply capacity must be checked.
• On PME, BS 7671 has specific EV requirements because of the open-PEN risk.
• Chargers need the RCD types their makers specify.
• The installer must notify the distribution network operator of a new charge point.
• Since 30 June 2022, under the Electric Vehicles (Smart Charge Points) Regulations 2021, new charge points sold in Great Britain for domestic or workplace use must have smart functionality, such as the ability to shift charging to off-peak times.

Expect an EIC and a compliance certificate. Do not charge a car through a domestic extension lead or cable reel; follow the vehicle maker's guidance on portable charging cables.

10.6 Solar Panels, Batteries and Heat Pumps

Roof-mounted PV is within the scope of Part P. PV, batteries and heat pumps involve new circuits, and PV and batteries add sources of supply that can stay live when the mains is off (Section 6.5); Amendment 4 of BS 7671 added a chapter on stationary batteries. None of this is homeowner work. Keep the isolation instructions by the consumer unit.

11.1 Extension Leads and Adaptors

A 13 amp socket and lead can supply 13 amps in total, about 3,000 watts; a four-way lead shares one socket's capacity four ways. Electrical Safety First and fire services advise:

• Check the rating: some older leads and many cable reels are 10 amps or less.
• Unwind cable reels fully: Electrical Safety First warns a wound reel may be rated at only 3 or 4 amps, and recommends reels with a thermal cut-out.
• Never plug one extension lead into another. This can overload the plug in the wall socket.
• Give high-power appliances (kettles, washing machines, heaters) a wall socket each.
• Avoid block adaptors, which can overheat, sag out of the socket and may be unfused; use a fused bar-type lead.
• Do not run leads under carpets.

If you rely on extension leads permanently, you need more sockets; ask an electrician.

11.2 Checking Plugs, Flexes and Appliances

With the appliance unplugged, look for:

• Cracked, chipped or scorched plug casings, or pins with brown heat marks.
• Flex damage: cuts, kinks, flattened sections, tape repairs, or coloured inner insulation visible where the outer sheath should be held by the cord grip.
• A hot plug, softening plastic or a smell (slight warmth after hours of heavy use can be normal).
• Appliances that trip RCDs, spark or give tingles.

Replace damaged flexes or plugs, or retire the appliance. Do not join flexes with tape or connector blocks.

11.3 Portable Heaters

A portable heater puts a lot of heat close to soft furnishings. Fire and rescue service advice includes:

• Keep heaters at least one metre from anything combustible, such as curtains, bedding, sofas and clothing.
• Plug heaters directly into a wall socket, not an extension lead.
• Never leave a heater on unattended or while you are asleep, and never use one to dry clothes.
• Avoid second-hand heaters, whose history and safety features are unknown.
• Stand heaters on a level surface where they cannot be knocked over, and choose models with a tip-over switch and overheat protection.

11.4 E-Bikes and E-Scooters

Lithium-ion battery fires spread fast and give off toxic smoke. London Fire Brigade's #ChargeSafe campaign reports an e-bike or e-scooter battery fire in London roughly every two days, many during charging. Its advice:

• Do not charge while you are asleep or out of the house. Unplug the charger once charging is complete.
• Use the correct charger: the one supplied with the device, or an official replacement from a reputable seller. LFB says many fires are caused by incompatible chargers, modified bikes, and faulty or counterfeit products bought online.
• Be wary of conversion kits that add a battery and motor to an ordinary bicycle, and of batteries bought from unknown online sellers.
• Keep escape routes clear. Do not store or charge e-bikes and e-scooters in hallways, on stairs or in communal corridors, where a fire would block your way out.
• Fit smoke alarms where you charge, and test them regularly.
• Watch for warning signs: a damaged or swollen battery, unusual heat, smell, hissing or popping, or a battery that suddenly holds less charge.

If a battery starts to smoke or catch fire, get everyone out, close the door behind you, and call 999. Do not try to fight it.

11.5 Product Recalls

Faulty appliances are recalled more often than many people realise. The Office for Product Safety and Standards publishes a searchable database on GOV.UK, Product safety alerts, reports and recalls, which you can filter by product category (including electrical appliances), risk level and date, and subscribe to by email. Check it when you buy a second-hand appliance, and periodically for larger items such as washing machines, tumble dryers, dishwashers and fridges. Registering new appliances with the manufacturer means they can contact you directly if a recall is issued.

Stop using a recalled appliance and follow the maker's instructions; do not pass it on.

12.1 How to Use the Fault Tables

Each entry gives the likely causes, what you can safely check without opening anything, and when to call an electrician. Anything that needs a cover off needs safe isolation first (Chapter 6).

12.2 Lights and Lighting Circuits

12.3 Sockets, Switches and Smells

12.4 Trips and Power Loss

12.5 Case Studies

12.6 Choosing and Checking an Electrician

1. Check registration on electricalcompetentperson.co.uk or the scheme's own register (for example NICEIC or NAPIT), making sure it covers your type of work and the business name matches.
2. Ask which certificates you will get: an EIC and, within 30 days, a compliance certificate for a new circuit or consumer unit; a Minor Works certificate for an addition; an EICR with full test schedules for an inspection.
3. Get written quotes covering the work, making good and notification.
4. Check insurance and complaints routes. Ask about the contractor's insurance, and ask the scheme about its complaints procedure and any warranty that applies to notifiable work.
5. Be wary of anyone who offers a cheaper price "without the paperwork", proposes a consumer unit change without testing the circuits, or issues an EICR after a very short visit.

Electrical Safety First's "find an electrician" service also searches the registers.

Notifiable work in England (Building Regulations 2010, regulation 12(6A))

Wales, Scotland and Northern Ireland have different rules (Section 4.6).

Protective devices at a glance

MCB types (BS EN 60898)

Colour codes

A blue or black core used as a switched line should be sleeved brown or red. A mix of old and new colours requires a warning notice at the consumer unit.

IP ratings (BS EN 60529), second digit

Plug fuses (BS 1362)

Key numbers

Checklist: before any replacement job

• Is this a like-for-like replacement, not an addition or a new circuit?
• Is the new accessory to the right British Standard, with the right IP rating and class for its location?
• Do I have a GS38-compliant two-pole voltage indicator and a proving unit?
• Do I know which circuit to isolate, and can I lock it off?
• Have I photographed the existing wiring?
• Do I know what I will do if I find damage, no earth, or voltage after isolation? (Stop and call an electrician.)

Checklist: routine

• Monthly: test smoke and carbon monoxide alarms.
• Six-monthly: press every RCD and RCBO test button.
• Yearly: check the circuit chart, look for heat marks and damage, search the recalls database, and note when the next EICR is due.

Editions relied on in this handbook

• BS 7671:2018+A4:2026, IET Wiring Regulations, 18th Edition incorporating Amendment 4 (published 15 April 2026), via public IET, NICEIC, SELECT, BEAMA and Electrical Safety First summaries. Bathroom zone details are from SELECT's summary of the A2:2022 text.
• Approved Document P, Electrical safety: Dwellings, 2013 edition (England).
• Approved Document B Volume 1, 2019 edition incorporating 2020, 2022, 2025 and 2026 amendments (England).
• Approved Document F Volume 1, 2026 edition (England).
• Approved Document J, 2010 edition incorporating 2010, 2013 and 2022 amendments (England).
• HSE GS38, fourth edition (2015).
• Electrical Safety First Best Practice Guide 2, Issue 4.2.
• GOV.UK guidance on electrical safety standards in the private and social rented sectors (November 2025) and on the Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022.