What a Full House Rewire Actually Involves

What a Full Rewire Actually Means

A full rewire is not simply a case of swapping old sockets for shiny new ones. It means stripping out the entire electrical installation — cables, back boxes, consumer unit, light fittings, switches — and replacing it with a modern, compliant system. In a typical UK home, that includes every circuit: lighting, power, immersion heater, smoke alarms, and often the earthing and bonding to gas and water services. The goal is simple: safe, reliable electricity that meets current regulations, including the 18th Edition of the Wiring Regulations and Part P of the Building Regulations.

For commercial premises, the same principle applies, but the scale and complexity multiply. Three-phase supplies, emergency lighting, fire alarm interlinks, and dedicated circuits for machinery all need careful design. Whether domestic or commercial, a rewire is a major project — but it is also the only way to guarantee that every hidden cable is fit for purpose.

Signs You Might Need a Full Rewire

Not every old installation needs a full rewire. A qualified electrician will test and inspect before recommending one. However, there are clear red flags:

• Rubber or fabric-covered cables — often found in homes wired before the 1960s. The insulation crumbles, leaving live conductors exposed.
• No earthing in lighting circuits — common in properties rewired before the 1966 regulations. This makes metal light fittings dangerous.
• A fuse box with rewireable fuses — no RCD protection means a fault can be fatal. Modern consumer units have RCBOs or RCDs.
• Frequent blown fuses or tripping — a sign that circuits are overloaded or damaged.
• Spurred sockets everywhere — a spaghetti of extensions suggests the original design cannot cope.
• An EICR report with C1 or C2 codes — these mean immediate danger or potential danger. A rewire is often the most sensible fix.

If you spot any of these, get a professional opinion. A full rewire is a big investment, but so is a house fire.

Before the Work Starts: Survey and Planning

A good rewire begins long before any cable is pulled. The electrician will carry out a full survey, including testing existing circuits, checking the earthing arrangement, and identifying any asbestos or structural quirks. You will then receive a detailed plan showing socket positions, light switch locations, consumer unit placement, and cable routes. This is your chance to add extra sockets, USB points, or dedicated circuits for a home office or electric vehicle charger.

For domestic jobs, you will need to agree a schedule. Most rewires take one to three weeks for an average three-bedroom house, but larger properties or those with solid stone walls can take longer. You will likely need to move out for at least part of the work — the power will be off for hours at a time, and dust and disruption are unavoidable. Commercial rewires are often phased to keep the business running, with work carried out evenings or weekends.

First Fix and Second Fix: What Happens When

A rewire happens in two main stages. During first fix, the electrician runs all the new cables through floors, ceilings, and walls. Floorboards come up, channels may be chased into plaster, and back boxes are fitted. This is the messy, noisy part. Temporary power may be provided via an extension lead from a neighbour or a generator.

Once the cables are in and tested, second fix begins. This is when sockets, switches, light fittings, and the consumer unit are connected. The electrician then carries out a full test and inspection, issuing an Electrical Installation Certificate. For commercial premises, you may also need a certificate of compliance with BS 7671 and, if applicable, a fire alarm certificate. Only after all testing is complete should the system be energised.

Commercial Rewires: Same Principles, Different Pressures

Commercial electrical services face unique challenges. A shop, office, or restaurant cannot simply close for two weeks. The rewire must be planned around trading hours, with temporary supplies and safe isolation procedures. You may need to maintain emergency lighting, fire alarms, and IT systems throughout. Three-phase supplies require careful load balancing, and any work must comply with the Electricity at Work Regulations 1989. A good commercial electrician will produce a phased programme, often working room by room or after hours, and will coordinate with other trades such as data cabling and HVAC engineers.

Costs, Certificates and Living Through It

Expect a full domestic rewire to cost between £3,000 and £8,000 for an average house, depending on size, access, and the number of fittings. Commercial costs vary widely — a small retail unit might start around £5,000, while a large warehouse can run into tens of thousands. Always get a detailed quote that lists what is included: making good, plastering, and certification are sometimes extra.

Once complete, you will receive an Electrical Installation Certificate and a Building Regulations Compliance Certificate (for domestic work in England and Wales). Keep these safe — they are essential when selling your property. A full rewire is disruptive, but it future-proofs your home or business for decades. With proper planning and a skilled electrician, you will end up with a safer, more efficient installation that just works.