Consumer Unit Upgrades & Smart Home Electrical Infrastructure
Penmilne upgrades household electrics to meet the demands of modern homes across Hertfordshire and Bedfordshire. Our NICEIC-approved electricians replace outdated fuse boards with BS 7671 compliant consumer units featuring RCBO and surge protection, wire garden offices and outbuildings, install dedicated circuits for high-demand appliances and prepare homes for smart lighting and automation.
NICEIC Approved Contractor, TrustMark endorsed, Aico Platinum Partner, ECA member and CHAS accredited. Serving Hertfordshire, Bedfordshire and Buckinghamshire from Hitchin since 1977.
Why upgrade an old fuse board or consumer unit?
Older fuse boards were designed for homes with far fewer appliances. Many have rewireable fuses, no residual current device (RCD) protection and plastic enclosures, and they are one of the most common reasons for C2 observations on an electrical inspection. A modern consumer unit protects people from electric shock, protects circuits from overload and makes faults far easier to isolate.
What does a modern consumer unit include?
| Feature | What it does | Why it matters |
|---|---|---|
| RCBOs | Combine overload and earth leakage protection for each individual circuit | A fault on one circuit does not switch off the whole house |
| Surge protection device (SPD) | Limits transient overvoltages from lightning or switching on the network | Protects sensitive electronics and is expected in most homes under BS 7671 |
| Non-combustible enclosure | Houses the consumer unit in a metal or equivalent non-combustible case | Required for domestic consumer units to help contain fire if a fault occurs |
| AFDDs | Detect dangerous arcing in cables and switch off the circuit | Required on socket circuits in HMOs and some higher-risk residential buildings, and recommended elsewhere |
Why does BS 7671 require non-combustible consumer units and surge protection?
Since 2016, BS 7671 has required consumer units in domestic premises to have an enclosure made of non-combustible material, or to be housed in a non-combustible cabinet. The change followed fires linked to plastic consumer units, often caused by loose connections overheating. In practice this usually means a metal-clad consumer unit.
The 18th Edition then extended the requirements for surge protection. Unless a risk assessment shows it is not needed, a surge protection device should be installed to protect the installation and connected equipment from transient overvoltages, so surge protection is now fitted as standard on almost every domestic consumer unit replacement.
Can you wire a garden office, studio or outbuilding?
Yes. A garden office needs a properly sized armoured sub-main cable from the house, its own protective devices and, depending on the earthing arrangement, a separate earth. Penmilne designs and installs the full supply, including lighting, heating circuits, sockets and Cat6 data cabling so the building has a reliable wired internet connection.
Which high-demand appliances need a dedicated circuit?
- Induction hobs and range cookers
- Air source heat pumps
- Electric showers
- Electric vehicle chargers
- Hot tubs and garden buildings
Adding several high-demand appliances can take a home close to the limit of its main fuse. Penmilne assesses the maximum demand of the installation before adding new circuits and advises if a supply upgrade from the network operator is needed.
What smart home electrical infrastructure can you install?
Smart homes work best when the wiring is planned in from the start. Penmilne installs structured Cat6 data cabling, neutral connections at switch positions for smart switches, architectural and feature lighting circuits, and external power for security cameras and gates. On new builds and major renovations this infrastructure goes in at first fix alongside the rest of the electrical work.
What homeowners say
Building our new home was certainly made easier by having Penmilne Electrical Contractors undertaking the electrical installation of our smart home. The works went entirely to plan, the electricians were on site when we needed them and nothing was too much trouble.
Mr & Mrs D, New build smart home, Campton
The team have gone into so much detail, offering us the best solutions to maximise the use of our garden home office, thank you.
W-P, Garden home office, Hitchin
They recently did some electrical work for us, which was solving an ongoing power issue, the electrician was professional and polite carrying out the work efficiently… I would certainly use this company again.
Mrs H, Clophill (consumer unit upgrade)
Consumer unit and smart home questions answered
Most domestic consumer unit replacements take around a day, including testing every circuit. Power is off for much of that time, so a convenient date is agreed in advance.
Every circuit is tested as part of the upgrade. Modern RCD protection can reveal existing faults that an old fuse board masked, so any issues are explained and quoted for before further work is carried out.
Yes. A consumer unit replacement is notifiable under Part P. You receive an Electrical Installation Certificate and a Building Regulations compliance certificate through NICEIC.
Often, yes. New high-demand circuits need spare capacity and suitable protection. The existing board is checked during the survey and any upgrade is included in the quotation.
Many smart switches need a neutral connection at the switch, which older installations often lack. Where there is no neutral, Penmilne can advise on compatible products or run new cables as part of wider works.
Yes. On new builds and extensions, data cabling, lighting circuits and smart control wiring are installed at first fix, which is far less disruptive than adding them later.