When people search for fit-out costs, the per-square-metre figure is usually the first thing they want. It is a reasonable place to start, but it only tells part of the story. This guide explains what the electrical element of a commercial fit-out actually costs per square metre in places like Marlow and Amersham, what drives that figure up, and how to use it sensibly when you are planning a budget.
Why does the per-square-metre figure vary so much?
Floor area drives the length of cable runs and the number of fittings, so it is a fair proxy for a baseline. But two units of identical size can have very different electrical costs depending on what goes inside them.
A small boutique with track lighting, a card reader and a kettle in the back office sits at the lower end of the range. A cafe with a commercial espresso machine, under-counter fridges, a heated display cabinet, extraction and a point-of-sale system with Wi-Fi throughout sits well above it. The floor area is the same; the electrical load is completely different.
The range at the top of this page reflects that spread. Treat it as a planning band, not a quote.
What is included in the electrical element of a fit-out?
When an electrician prices a commercial fit-out, the scope typically covers:
- Consumer unit or distribution board, sized for the premises
- Power circuits for sockets, equipment and any dedicated appliance feeds
- Lighting circuits, including switching and any dimming or scene control
- Emergency lighting throughout, with test facilities
- Fire alarm interface if a separate fire alarm contractor is involved
- Data and communications cabling if agreed in scope
- External signage supply if required
- Testing, certification and building control notification where applicable
Everything else, structural, plumbing, decoration, joinery, is a separate trade. The figures on this page cover only the electrical work.
What pushes the cost per square metre up?
Several things move the needle significantly.
Three-phase supply. If your equipment list includes a commercial oven, large air-conditioning units or industrial machinery, you may need a three-phase supply. If the building does not already have one, arranging a new supply from the street involves the network operator as well as your electrician, and it adds both cost and time to the programme.
Commercial kitchens. Even a small cafe kitchen is dense with dedicated circuits. Each piece of equipment, the range, the extraction, the dishwasher, the fridge, the hot-water boiler, needs its own protected feed. Kitchen electrical work regularly costs two or three times as much per square metre as the front-of-house area.
Emergency lighting. This is not optional in any space where staff or customers work. The number of fittings is determined by the layout, not just the floor area, and a complex floor plan with corridors, a back office and a WC will need more fittings than an open room of the same total size.
Data infrastructure. A modern retail or office fit-out almost always needs structured cabling for broadband, Wi-Fi access points and EPOS terminals. Running this alongside the power circuits is efficient, but it adds to the overall cost. Agreeing the data layout before first fix begins avoids expensive changes later.
Existing wiring condition. If you are taking on a unit that has been empty for some time, or one where the previous tenant’s wiring was done poorly, there may be remedial work before the new fit-out can begin. An Electrical Installation Condition Report at the start of the project identifies any problems early.
What does a typical Marlow cafe or Amersham office actually cost?
Rather than invented figures, it is more useful to think in terms of what each type of premises tends to involve.
A small retail unit, say a boutique or a letting agency, in a modern building with a decent existing supply will sit toward the lower end of the range. The electrical scope is relatively straightforward: general power, lighting, emergency lighting and perhaps a data point or two.
A cafe or sandwich bar, even a modest one, moves toward the middle of the range because of the kitchen circuits. If it has a commercial coffee machine on a dedicated feed, extraction on a separate circuit and a point-of-sale system with Wi-Fi, the electrical content is substantial relative to the floor area.
An office fit-out in Amersham or Gerrards Cross, with open-plan desking, a server room or comms cabinet, air conditioning and a full data infrastructure, can sit anywhere in the range depending on the specification. A high-spec fit-out with motorised blinds, scene-setting lighting and a managed network will cost more per square metre than a simple open-plan office with strip lights and double sockets.
For a full picture of what commercial electrical work involves from start to finish, see the guide to commercial electrical fit-outs in Beaconsfield.
How is the work structured on site?
Commercial electrical fit-outs follow the same first-fix and second-fix sequence as domestic work, but the programme is tied closely to other trades.
First fix happens after the structure is open but before plastering or ceiling tiles go in. This is when cable routes are established, back boxes are positioned and any conduit is installed. Getting the cable routes agreed before first fix is critical, because moving them later means opening up finished surfaces.
Second fix happens once the space is decorated and ready for fittings. Sockets, switches, luminaires and equipment connections are all made at this stage. Emergency lighting is commissioned and tested. The installation is then inspected and tested as a whole before the certificates are issued.
If the programme is tight, the electrician needs to know when each area will be ready for each stage. Waiting for another trade to finish a section before cables can be run is one of the most common causes of delay on fit-out projects.
What should I have ready before asking for a quote?
The more information you can provide, the more accurate the quote will be. Useful things to have to hand include:
- A floor plan, even a rough one, showing the intended layout
- An equipment list, particularly anything with a significant electrical load
- Details of the existing supply, including whether it is single or three-phase
- Any data or communications requirements
- Your target completion date and the programme for other trades
If you do not have all of this yet, a site visit is often the most efficient way to get a realistic figure. An experienced electrician can walk a unit, ask the right questions and give you a meaningful budget range without needing a full set of drawings.
How do I get a price for my fit-out?
JC Electrical works with small businesses across South Bucks and the surrounding area, including Marlow, Amersham, Gerrards Cross and Beaconsfield. If you have a unit to fit out, or you are at the planning stage and want a budget figure, use the contact form or phone number on this page to send the details across. A brief description of the premises, the type of business and the rough floor area is enough to get the conversation started.
