The jargon, translated

BS 7671, the IET Wiring Regulations, is the UK standard for how electrical installations must be designed, installed and tested; the current version is the 18th Edition with amendments.

The 18th Edition was published in 2018 and has been updated by amendments since, most noticeably Amendment 2 in 2022, which changed the rules on surge protection, arc fault detection and EV charging. It is not itself the law, but it is the standard that Part P and the landlord regulations point to, so an installation is judged against it. Electricians sit an exam on each new edition, which is why you will see 18th Edition on their cards.

See: EICRs and landlord certificates, Commercial inspection and testing, What is an EICR and how often do you need one?, Part P explained: what you can legally do yourself, How to check an electrician is properly qualified

C1, C2, C3 and FI are the grades used on an EICR: C1 means danger present, C2 potentially dangerous, C3 improvement recommended, and FI further investigation required.

Any C1, C2 or FI makes the report unsatisfactory, and a C1 should be made safe before the electrician leaves. C3 items are advisory, so a report with only C3s is still satisfactory. Landlords in England must fix C1, C2 and FI findings within 28 days of the report or sooner if it says so. A common C2 in older Blackpool properties is a consumer unit with no RCD protection for the sockets.

See: EICRs and landlord certificates, Commercial inspection and testing, What is an EICR and how often do you need one?, Landlord electrical safety rules explained, Electrics for Blackpool guest houses and holiday lets

A consumer unit, often called the fuse box, is the enclosure where your electricity supply is split into circuits, each protected by a fuse, MCB or RCBO.

Modern units are metal, as required for homes since 2016, and have a main switch, RCD protection and a row of circuit breakers labelled for lights, sockets, cooker, shower and so on. Older boards with rewirable fuses, a plastic case or no RCD still work but offer much less protection. Replacing one is notifiable work under Part P and should come with an Electrical Installation Certificate.

See: Consumer unit upgrades, House rewires, Signs your fuse box needs replacing, Part P explained: what you can legally do yourself, Why does my RCD keep tripping?

Earthing gives fault current a safe path back to the supply so protective devices trip; bonding connects metal pipework to that earth so nothing can sit at a dangerous voltage.

Main bonding runs from the consumer unit's earth bar to the incoming gas and water pipes, usually in green and yellow 10 mm cable. Missing or undersized bonding is one of the most common findings on EICRs in older houses and is usually quick to put right. Plastic incoming pipes do not need bonding, which is why newer estates in Poulton and Thornton often have none, and that is correct.

See: EICRs and landlord certificates, House rewires, Consumer unit upgrades, What is an EICR and how often do you need one?, Signs your house needs a rewire

An Electrical Installation Certificate is issued for a new installation, a new circuit or a consumer unit replacement, confirming the work was designed, built and tested to BS 7671.

It is different from an EICR: an EIC covers new work, an EICR checks existing wiring. The certificate lists the test results for every circuit, names the people responsible for the design, construction and testing, and should come with a schedule of inspections and test results. You should receive one after a rewire or a new consumer unit, and you will need it when selling the house or if a buyer's surveyor asks. Keep it with the deeds.

See: Consumer unit upgrades, House rewires, EV charger installation, Hot tub electrical supplies, Part P explained: what you can legally do yourself, How to check an electrician is properly qualified

An EICR (Electrical Installation Condition Report) is a formal inspection and test of a building's fixed wiring that records whether it is safe to keep using.

The electrician inspects the consumer unit, cables, sockets, switches and earthing, runs tests on each circuit, and grades any problems with the codes C1, C2, C3 and FI. The report is either satisfactory or unsatisfactory. Private landlords in England must have one at least every five years, and homeowners are generally advised to have one every ten years or when buying a house. On the Fylde coast, salty air and older guest-house wiring mean we find more corroded terminals and tired consumer units than you might expect.

See: EICRs and landlord certificates, Commercial inspection and testing, What is an EICR and how often do you need one?, Landlord electrical safety rules explained, Electrics for Blackpool guest houses and holiday lets

Emergency lighting is battery-backed lighting that comes on automatically when the mains fails, so people can find their way out of a building safely.

It is required in most non-domestic premises and in the shared areas of flats, guest houses and houses in multiple occupation, under the fire safety order and BS 5266. The usual regime is a short function test every month and a full-duration test, normally three hours, once a year, both recorded in the fire log book. Battery packs wear out, so an annual test often turns up a few fittings that light up but do not last.

See: Emergency lighting and fire alarms, Commercial inspection and testing, Electrics for Blackpool guest houses and holiday lets

First fix is the cabling, back boxes and consumer unit installed before plastering; second fix is fitting the sockets, switches, lights and board, then testing, after the walls are finished.

On a rewire the first fix is the messy stage, with floorboards up and chases cut in the walls, and the second fix is when the house starts to look normal again. The gap between them is for the plasterer and decorator, so the overall job takes longer than the days we are on site. Knowing the two stages helps you plan who stays where in the house and when the carpets can go back.

See: House rewires, Consumer unit upgrades, Signs your house needs a rewire

Fixed-wire testing is the commercial name for an EICR: a periodic inspection and test of a building's permanent wiring, as opposed to the portable appliances plugged into it.

Offices, shops and similar premises are usually tested every five years, with shorter intervals for places such as swimming pools, caravan parks and industrial units. The work is planned around the business, often circuit by circuit so nothing is off for long, and the report gives the owner evidence for insurers and the fire risk assessment. For a guest house or a block of flats it is the same inspection a landlord needs.

See: Commercial inspection and testing, EICRs and landlord certificates, What is an EICR and how often do you need one?, Electrics for Blackpool guest houses and holiday lets

An MCB (miniature circuit breaker) is the resettable switch in a consumer unit that trips when a circuit draws too much current, replacing the old rewirable fuse.

Each MCB is rated for its circuit: typically 6 A for lighting, 32 A for a ring of sockets, 40 A or more for a shower. It protects the cable from overheating, not people from shocks, which is why it is paired with an RCD or built into an RCBO. If an MCB trips repeatedly, something on that circuit is overloaded or short-circuiting and simply resetting it is not the answer.

See: Consumer unit upgrades, Electrical fault finding, Signs your fuse box needs replacing, Why does my RCD keep tripping?

A Minor Electrical Installation Works Certificate covers small additions or alterations to an existing circuit, such as an extra socket, that do not add a new circuit.

It records that the work was tested and that the circuit it joined is safe to extend, including a check on the earthing and the RCD. It is shorter than a full Electrical Installation Certificate because the rest of the circuit already exists. Many small jobs still need one, so if an electrician adds a spur in your kitchen in Cleveleys and leaves without any paperwork, ask for it.

See: Outdoor power and lighting, Electrical fault finding, Part P explained: what you can legally do yourself, How to check an electrician is properly qualified

NICEIC is one of the UK's main certification bodies for electrical contractors, which assesses firms each year and registers them to self-certify notifiable work under Part P.

Approved Contractor status covers commercial and industrial work as well as domestic, while the Domestic Installer scheme is for home work only. Every registered firm is listed on the NICEIC online register, so you can check a company before you hire it, and if work is found to be below standard there is a complaints process. NICEIC is not the only such body: NAPIT, ELECSA and others run similar schemes, and all are equally valid under Part P.

See: EICRs and landlord certificates, Consumer unit upgrades, Commercial inspection and testing, How to check an electrician is properly qualified, Part P explained: what you can legally do yourself

Notifiable work is electrical work in a home that must be reported to building control under Part P, such as a new circuit, a consumer unit change or bathroom work.

The simplest route is to use an electrician registered with a competent person scheme, who notifies the job for you and arranges a compliance certificate from the scheme. If you do notifiable work yourself, or use someone unregistered, the council must be told before you start and will charge to inspect it. Adding a socket to an existing circuit in a dry room is not notifiable, but it still has to meet BS 7671 and should get a Minor Works Certificate.

See: Consumer unit upgrades, House rewires, Hot tub electrical supplies, Part P explained: what you can legally do yourself

OZEV is the Office for Zero Emission Vehicles, the government body that runs the grants for installing electric vehicle charge points and approves the installers who can claim them.

The homeowner grant for houses with driveways ended in 2022, but at the time of writing OZEV grants are still available in some cases for flats, rented homes, landlords and small businesses, with the amounts and rules changing from time to time. The grant is claimed by an OZEV-authorised installer, not by you, and is taken off the invoice. Check the current gov.uk pages before you count on it.

See: EV charger installation, EV charger installs: what's involved and what it costs

Part P is the section of the Building Regulations for England and Wales that requires electrical work in homes to be safe, with certain jobs notified to building control.

Notifiable jobs include a new circuit, a consumer unit replacement and most work in bathroom zones. A registered electrician notifies the work through their competent person scheme and you receive a compliance certificate; otherwise you must apply to the council's building control yourself and pay a fee. Unnotified work can hold up a house sale, because the buyer's solicitor will ask for the certificates.

See: Consumer unit upgrades, House rewires, EV charger installation, Part P explained: what you can legally do yourself, How to check an electrician is properly qualified

PAT testing (portable appliance testing) is the inspection and testing of plug-in equipment such as kettles, lamps and extension leads to confirm they are safe to use.

The law requires employers and landlords of furnished lets to keep equipment safe but does not set a fixed interval; the IET Code of Practice suggests how often, based on the type of equipment and where it is used. Each item gets a visual check, an electrical test where needed and a pass or fail label, and you receive a register. Guest houses on the South Shore usually have it done before the season starts, along with the fire alarm and emergency lighting checks.

See: PAT testing, Commercial inspection and testing, Electrics for Blackpool guest houses and holiday lets, Landlord electrical safety rules explained

A PME or TN-C-S supply is the most common mains earthing in UK homes, where the supplier provides the earth through the combined neutral and earth of the incoming cable.

It works well indoors, but if the supply neutral is ever lost, metalwork connected to a PME earth can become live. That is why the regulations place extra conditions on EV chargers, hot tubs and outbuildings fed from a PME supply: either a charger with built-in open-PEN protection or a separate earth rod. It is one of the first things we check on a survey, because it changes what kit is needed and the price.

See: EV charger installation, Hot tub electrical supplies, Outdoor power and lighting, EV charger installs: what's involved and what it costs, What supply does a hot tub need?

A radial circuit is a single cable run from the consumer unit that feeds its points in turn and simply ends at the last one, with no return leg.

Lighting, cookers, showers, EV chargers and hot tubs are all on radials, and sockets can be too, especially in kitchens, outbuildings and newer builds. Radials are simpler to test and fault-find than rings because there is only one path. The cable and breaker are sized together, so a 20 A radial in 2.5 mm cable suits a small run of sockets, while a shower needs a 10 mm radial on its own.

See: House rewires, EV charger installation, Hot tub electrical supplies, Outdoor power and lighting, What supply does a hot tub need?

An RCBO combines an RCD and an MCB in one device, so a single circuit gets both earth-leakage and overload protection without affecting the others.

In an older split-load board one RCD covers several circuits, so a fault on the outdoor socket can also take out the fridge and the freezer. With RCBOs each circuit trips on its own, which makes faults easier to find and keeps the rest of the house running. They cost more per way, which is why a new consumer unit fitted with RCBOs throughout costs more than one with two shared RCDs. For holiday lets and guest houses the extra is usually worth it.

See: Consumer unit upgrades, Signs your fuse box needs replacing, Why does my RCD keep tripping?, Electrics for Blackpool guest houses and holiday lets

An RCD (residual current device) is a safety switch that cuts the power in a fraction of a second when it detects electricity leaking to earth, perhaps through a person.

A 30 mA RCD is the standard for protecting sockets, bathrooms and outdoor circuits in homes. It does not protect against overloads, which is the job of the MCB, so the two work together. Nuisance tripping is usually caused by a faulty appliance, damp in an outside socket or a worn immersion heater rather than the RCD itself. A consumer unit with no RCD at all is one of the clearest signs it is due for replacement.

See: Consumer unit upgrades, Electrical fault finding, Outdoor power and lighting, Why does my RCD keep tripping?, Signs your fuse box needs replacing

A ring final circuit is the UK way of wiring sockets: a loop of cable starting and ending at a 32 A breaker, so current reaches each socket both ways.

It lets a modest cable serve a whole floor of sockets. The weakness is that a break in the ring goes unnoticed, leaving one leg carrying everything, which is why an EICR includes a ring continuity test. Spurs can be added from the ring, but only one socket per spur without a fused connection unit, and a ring that has been extended many times over the years is a common reason for an unsatisfactory report.

See: House rewires, EICRs and landlord certificates, Electrical fault finding, What is an EICR and how often do you need one?, Signs your house needs a rewire

An SPD (surge protection device) sits in the consumer unit and absorbs brief voltage spikes, protecting electronics such as boilers, TVs and EV chargers from damage.

Surges come from lightning nearby or from switching on the wider network, and they can quietly shorten the life of anything with a circuit board. The current Wiring Regulations expect surge protection in most new consumer units and installations, with limited exceptions, so a new board will normally include one. It is a small module and is usually the cheapest insurance you will buy for a house full of smart kit.

See: Consumer unit upgrades, EV charger installation, Signs your fuse box needs replacing

SWA is steel wire armoured cable, a tough cable with steel wires under its sheath, used for underground runs and outdoor supplies to sheds, hot tubs and chargers.

The armour protects the cores from damage and can also serve as the earth. It is buried at a safe depth with warning tape above it, or clipped along walls and fences where it is out of harm's way. The cable size depends on the load and the length of run, so a 32 A hot tub supply across a long garden in Lytham may need a bigger cable than the same tub by the back door.

See: Hot tub electrical supplies, Outdoor power and lighting, EV charger installation, What supply does a hot tub need?

TrustMark is the government-endorsed quality scheme for tradespeople working in and around the home, covering technical competence, customer service and trading practices.

A TrustMark-registered firm has been vetted by a scheme provider, carries the right insurance, and offers a route to dispute resolution if something goes wrong. For electrical work it sits on top of scheme registration rather than replacing it, so look for both. TrustMark registration is also required for some government-funded energy efficiency work, which matters if a grant is paying for part of the job.

See: How to check an electrician is properly qualified, Consumer unit upgrades, House rewires