Dangerous DIY Electrics in Bristol

I understand the appeal of DIY. But when it comes to electrical work, the consequences of getting it wrong are not a wonky shelf or a badly tiled splashback. They are house fires, fatal electric shocks, and serious legal problems.

Every year I get called out to properties across Bristol to fix dangerous DIY electrical work — melted cables, incorrectly wired consumer units, outdoor sockets with no earth protection. Some of these situations were genuinely life-threatening.

Here are eight electrical jobs you should never attempt yourself, and why.

1. Replacing a Consumer Unit (Fuse Board)

This is probably the single most dangerous DIY job I see. Your consumer unit controls every circuit in the property, and replacing one involves working very close to the live main supply.

It must be designed correctly — the right MCBs and RCDs for each circuit, proper cable sizing, and full compliance with BS 7671 (the IET Wiring Regulations). Get any of this wrong and you could have circuits that do not trip when they should, leaving you exposed to electric shock or fire.

Under Part P of the Building Regulations, this is notifiable work. It must be carried out by a registered electrician or you must apply for Building Control approval before starting. Without a proper Electrical Installation Certificate, you face problems with insurance and when selling.

If you need a new fuse board, have a look at our consumer unit upgrade page for what is involved.

2. Adding New Circuits

Adding a new circuit — whether for a kitchen extension, an electric shower, or a garden office — is notifiable work under Part P. It requires correct cable sizing for the load and length of run, appropriate protective devices, and full testing and certification.

I have seen DIY circuits wired with cable that is too thin for the load, protected by the wrong size breaker, and with no RCD protection. The cable overheats, the insulation degrades, and eventually something gives.

3. Any Electrical Work in Bathrooms

Bathrooms are classified as a special location under BS 7671 because of the danger of water and electricity mixing. The regulations define specific zones around baths, showers, and basins, each with strict rules about what can be installed.

Even fitting a new bathroom light or extractor fan is notifiable if it involves a new circuit or work in the defined zones. I have been called to properties in Southville and Bedminster where homeowners fitted standard light switches within the bathroom zones — where they are not permitted under Section 701 of BS 7671. Switches must be located outside zones 0, 1, and 2, or be pull-cord operated with insulating cords. All bathroom circuits must have 30mA RCD protection.

4. Electrical Work in Kitchens Near Sinks

Kitchens present similar risks to bathrooms. The area around the kitchen sink is subject to special requirements, and any new circuit work in a kitchen is notifiable. Sockets must be positioned correctly relative to the sink, and circuits must have appropriate protection.

I regularly see extension leads draped across kitchen worktops and over sinks — a serious electric shock risk. If you need more sockets in your kitchen, a qualified electrician can add them safely and in compliance with the regulations. Our lighting and power service covers exactly this kind of work.

5. Outdoor and Garden Wiring

Garden lighting, pond pumps, power to a shed, outdoor sockets — all notifiable under Part P. Outdoor circuits must be protected by a 30mA RCD, and cables must be suitable for outdoor use and either buried at the correct depth or run in appropriate containment.

I have found indoor-rated cable run across garden fences, buried inches under flower beds with no protection. One homeowner in Horfield had run a household extension lead through a window to power their garden lights permanently — a genuine electrocution risk in wet weather.

Have a look at our outdoor electrics page if this is something you need.

6. Working on the Main Supply (Before the Meter)

This should go without saying, but never touch anything on the supply side of your electricity meter. The cables between the meter and the street carry the full incoming supply and are not protected by your consumer unit. Contact with these cables can be instantly fatal.

Only your Distribution Network Operator (DNO) or a qualified electrician working under specific protocols can carry out work on the main supply. This is not a grey area — it is a hard line.

7. Rewiring or Extending Circuits Behind Walls

Chasing cables into walls and running new wiring behind plaster is skilled work. Cables must be run in permitted zones (vertically or horizontally from sockets and switches) or protected with an RCD or mechanical protection. If cables are buried randomly, someone putting up a shelf could drill straight through a live cable.

A house rewiring involves starting fresh with modern cables, correct containment, and full testing. I was recently called to a property in Clifton where the previous owner had extended a lighting circuit by twisting cables together inside a ceiling void and wrapping them in tape. The tape had degraded and the bare conductors were millimetres apart. Pure luck it had not already caused a fire.

8. Installing an EV Charger

With more people switching to electric vehicles, this comes up a lot. An EV charger draws a significant load — typically 7.4kW on a dedicated 32A circuit — and must comply with BS 7671, the IET Code of Practice for EV Charging, and Part P.

It is not just plugging in a unit. It involves assessing your supply capacity, installing a dedicated circuit, fitting appropriate protection (including an RCD and often additional DC fault protection), and ensuring the earthing is correct. Some older properties in areas like Redland and Cotham need a supply upgrade before an EV charger can be fitted.

Our EV charger installation page explains the full process.

What Happens If You Do DIY Electrical Work?

The consequences are serious:

• Safety: Faulty wiring kills. A significant number of the thousands of UK house fires each year are caused by poor electrical work.
• Insurance: If your insurer discovers unqualified electrical work without Building Control sign-off, they can refuse to pay a claim — including fire damage.
• Selling your home: The buyer’s solicitor will ask for electrical certificates. If you cannot provide them, the sale can fall through or you will need a full EICR inspection and remedial work at your expense.
• Legal liability: Part P is a legal requirement. Non-compliant work can result in enforcement action and a requirement to have the work redone by a registered electrician.

What You CAN Do Yourself

Homeowners can legally carry out like-for-like replacements outside special locations (bathrooms, kitchens). That means:

• Replacing a socket or light switch with the same type, in the same location
• Replacing a ceiling light fitting (turning off the supply first)
• Replacing a damaged plug on an appliance

The key word is “like-for-like.” If you are adding something new or moving something, you are likely into notifiable work territory. If in doubt, ask. MB Electrical covers all of Bristol — call us on 07580 060560 or request a free electrical quote.

Frequently Asked Questions

Can I change a light fitting myself?

Yes, replacing a light fitting on a like-for-like basis is generally permitted, provided you turn off the supply at the consumer unit and the work is not in a bathroom. If you are adding a new light where one did not exist before, that is a different matter and may require a qualified electrician.

What is Part P of the Building Regulations?

Part P covers electrical safety in dwellings in England and Wales. It requires that most electrical installation work is carried out by a registered competent person (such as a NAPIT or NICEIC registered electrician) or notified to Building Control before work begins. The aim is to ensure all work meets BS 7671 safety standards.

Will my home insurance cover damage from DIY electrics?

Most home insurance policies require that electrical work is carried out by a qualified person or complies with Building Regulations. If a fire or other damage is caused by non-compliant DIY wiring, your insurer can refuse to pay the claim. Some policies are more explicit about this than others, so check your policy wording.

How do I know if an electrician is properly qualified?

Look for registration with a government-approved competent person scheme such as NAPIT, NICEIC, or ELECSA. Registration means the electrician is regularly assessed, their work is inspected, and they can self-certify their work under Part P without needing to involve Building Control. You can verify registration on the relevant scheme’s website.