Your electrical paperwork, in English.

A full inspection and test of an existing installation, ending in a written report that classifies everything found. It's a health check on the wiring, not a certificate for new work.

→ Recommended every 5 years for rented accommodation and roughly every 10 years for an owner-occupied home — and it's the document a letting agent or solicitor will ask for.

Something on the installation presents a risk of injury right now — exposed live parts, for example.

→ It gets made safe on the day, before we leave. You'll be told about it while we're still on site, not in an email a week later.

Not dangerous at this moment, but it could become so — a missing earth, an unsuitable protective device, damaged cable inside an enclosure.

→ This is the code that makes a report 'unsatisfactory'. It needs remedial work, and we'll price it separately so you can compare.

It complied with the regulations in force when it was installed but wouldn't be done that way today.

→ A C3 on its own doesn't fail a report. It's useful information for planning, not a reason to panic or to be pressured into rewiring.

Something couldn't be fully assessed on the day and needs opening up or testing further before it can be coded properly.

→ It also makes a report unsatisfactory, so we'd rather resolve it during the inspection than leave you holding an ambiguous document.

Issued for new installations and for significant new work — a rewire, a new consumer unit, a new circuit such as a car charger or hot tub supply.

→ Keep it with the house paperwork. It's the proof the circuit was designed, installed and tested correctly, and buyers' solicitors do ask.

Used for alterations and additions to an existing circuit that don't involve a new circuit — moving a socket, adding a light point.

→ Small job, still certificated. If someone does alteration work and hands you nothing at all, that's worth noticing.

The part of the Building Regulations covering electrical safety in dwellings. Certain work in a home is notifiable to building control.

→ Notifiable work needs to be certified and notified properly — it's the bit that quietly matters when you come to sell.

The national standard for electrical installation in the UK. Everything we install or alter is designed and tested against it.

→ It's the yardstick your certificate is measured against — so 'tested to the 18th Edition' is a statement with something behind it.

A protective device that combines overload protection with residual current protection on a single circuit.

→ In an RCBO board, a fault on one circuit trips only that circuit. On older split-load boards, one fault takes out half the house — including the freezer.

Fitted in the consumer unit to clamp transient overvoltages from lightning or switching events on the network.

→ We fit one as standard with a new board. It's inexpensive at the time of installation and protects everything expensive plugged in downstream.

Two digits describing how well an enclosure resists solids and water. The second digit is the one that matters outdoors and in bathrooms.

→ It's why a garden fitting costs what it costs. The wrong IP rating in the wrong place is the single most common reason outdoor lights fail in their second winter.