What Is The Difference Between A Cat A And Cat B Electrical Fit Out?

If you’re planning a commercial space or office space fit out in London, one term you’re bound to hear early on is whether the job is a category A (cat A) or category B (Cat B) project. These two stages refer to very different scopes of work, especially when it comes to electrical installations.

As electrical contractors working across London, we regularly work on commercial property fit outs with wide-ranging complexities. Here, we’ll run through the specifics to help you understand the different types of fit out project and the level of finish each provides.

What are the different types of fit outs?

What is an office fit out? It goes way beyond office design and into the intricacies of architecture, construction, electrics and engineering. Here, we explain the electrical aspects of office fit outs (our specific area of expertise).

1. What is a shell and core fit out?

This is the basic structure – the bare bones or empty shell – of the building. It includes the main structure, exterior and communal areas, but leaves the interior space undeveloped.

2. What is a Category A fit out?

A Category A (Cat A) fit out is the basic finish, typically completed by the landlord or developer, to make the space functional and ready to lease. It should meet building regulations and safety requirements. Cat A spaces tend to have:

• Basic floor finishes (like raised access floors)
• Structural elements (ie walls, floors and suspended ceilings)
• Common areas like hallways, staircases, lifts, lobbies, reception areas and toilets are part of Cat A fit-outs.
• From an electrical point of view, this means installing:
• Basic mechanical services and electrical services
• Fire detection systems (like smoke alarms)
• Electrical distribution boards and risers
• Heating, ventilation, air conditioning (HVAC systems)
• Standard LED lighting
• Emergency lighting systems
• Power to floor boxes or perimeter sockets
• Containment (trunking, conduits) for future cabling.

Essentially, a Cat A project creates a blank canvas for incoming tenants. It’s operational, but it allows the tenants to customise the space according to their specific needs.

You may also have heard of a mid-level of finish known as Cat A+. This is a plug-and-play office fit out that’s finished to a generic level, but without bespoke design elements. It’s attractive to businesses that simply want to move in and add their branding and signage to make it look like their own space.

3. What is a Cat B fit out?

A Category B fit out transforms the basic workspace into a fully functional working environment customised to the specific requirements of a business.

• Partitioning (eg meeting rooms, breakout areas, private offices)
• Interior design
• Business brand identity
• Flooring, wall finishes and decorations
• Furniture, fitted kitchens, breakout spaces.

Category B electrical systems and installations typically involve:

• Relocation or addition of power outlets to match workstations
• IT infrastructure, data cabling, network points and comms racks
• Audio-visual (AV) installations (projectors, screens, video conferencing tech)
• Feature lighting (task lighting, pendant lights, accent lighting)
• Kitchen electrics (fridges, microwaves, vending machines, tea points)
• Security systems (access control, intruder alarms and CCTV)
• Specific power supply and electrical systems specific to that business.

As you can see, the category B fit out is the most complex. It transforms an empty shell or catA office space into a customised workspace that works for your specific business. The cat B office fit out stage is very detailed. Each electrical installation is tailored to fit the actual business operations. That means adequate power sockets for each workstation. The all important tea points. And no business can run without efficient IT infrastructure these days.

Case study: 33 Kingsway, London

We’re proud to have played a key role in transforming 33 Kingsway into a dynamic and modern workspace. We were responsible for the full suite of electrical and data services. This project reflects our commitment to enhancing workspace functionality through smart, efficient and future-proofed electrical solutions.

Explore our commercial office fit out project in Central London.

Put your electrical office fit out in safe hands

If you’re moving to a new office building or taking occupancy of one that needs refurbishment, you need a contractor that you can trust. It takes skill and expertise to transform an empty shell into a customised workspace that meets your business’ specific needs.

Our electrical contractors are experienced, professional and NICEIC certified. With complex commercial and industrial electrical installations, you need to know that the team’s adequately trained and that your premises and people are in safe hands.

We tailor our commercial electrical fit out services to meet the unique needs of each client. We provide bespoke solutions, combining our technical expertise and strict compliance with safety standards. Please get in touch to discuss your specific needs and to discuss fit out costs.