What electrical work am I allowed to do myself?

Where the line sits between a job you can do and one that must be certified, and why the paperwork matters as much as the safety.

Difficulty: beginner
Time: 15 min
Read: 2 min
Safety: restricted

Short answer

Like-for-like replacement of an existing accessory — a socket front, a switch, a light fitting — is generally permitted. New circuits, consumer unit work, and anything in a bathroom or outdoors is notifiable and needs a registered electrician.

There are two separate questions: is it safe for you to do, and is it legal to do without certification. They do not have the same answer, and the second one is what causes problems years later when a house is sold.

Safety

Electrical work can kill, cause fires, and invalidate your insurance and your ability to sell the house. Some work is legally notifiable and must be done or certified by a competent registered person. This guide explains where the line sits — it is not instructions for carrying out electrical work. If you are not certain a job is on the permitted side of the line, it is not.

Step by step

Understand what notifiable means.Certain work must be notified to building control or carried out by a registered competent person who self-certifies it. Doing it without that is an offence and leaves the house without the certificate a buyer's solicitor will ask for.
Know what is generally permitted.Replacing a socket front, switch or light fitting like for like on an existing circuit. Replacing a damaged cable on a like-for-like basis. Adding a fused spur to an existing circuit outside special locations.
Know what is not.New circuits, work on the consumer unit, and any work in a bathroom or shower room, outdoors, or near a swimming pool. These are notifiable regardless of how simple they look.
Treat bathrooms and outdoors as off limits.Water and electricity together is why these are special locations. Zones, bonding and RCD protection all apply and get judged by rules most people have never read.
Always test before touching anything.Turn off at the consumer unit, lock or label it, and confirm dead with a proper voltage tester on a known-live circuit first. A circuit that looks off may not be.
Never assume the existing wiring is correct.Old colour codes, previous DIY, borrowed neutrals and unlabelled circuits are all common. What is there is not evidence of what should be there.
Get an electrical condition report if you are unsure.An EICR tells you the state of the installation. Worth it when buying a house, or on anything older than about 25 years.
Get certification for anything notifiable.A registered electrician self-certifies and issues the paperwork. Keep it — it is what proves the work was done properly when you sell.

Tips

Rules differ across the UK. Scotland, England and Wales have different building standards, so check what applies where you are.
A part-finished DIY electrical job is worse than none. Electricians frequently charge more to correct one than to have done it originally.
If you cannot say confidently which circuit something is on and how it is protected, that is your answer.

Common mistakes

Assuming simple means permitted — A socket in a bathroom is no harder to fit than one in a bedroom, and it is notifiable. Difficulty and legality are unrelated.
Not getting certification — The absence of paperwork surfaces at sale, when a buyer's solicitor asks. Retrospective certification is expensive and sometimes impossible.

Questions people ask

Can I change a socket myself?

Replacing an existing socket like for like on an existing circuit is generally permitted outside special locations such as bathrooms. New circuits and consumer unit work are not.

What happens if I do notifiable work without certification?

It is an offence, it may invalidate insurance, and it will be raised when you sell. Retrospective certification is expensive and sometimes not possible.