Commercial Electrical Installation

A commercial electrician works on business premises, where the loads are larger, the installations are more complex and the people using the building are employees and the public. The work includes:

• Design: Working out the loads, the supply needed, the circuits and the protection, to BS 7671.
• Supply and distribution: Single-phase and three-phase supplies, main switchgear, sub-mains and distribution boards.
• Power: Small power for workstations, tills and equipment, and dedicated circuits for kitchens, machinery and servers, as well as air conditioner installation and workplace EV charger installation.
• Lighting: General, task, display and external lighting, with controls and emergency lighting.
• Testing, certification and maintenance: An Electrical Installation Certificate for new work, and inspection and testing over the life of the building.

Part P of the building regulations applies to homes, not commercial premises. Commercial work is still designed, installed and certified to BS 7671, and employers and those in control of premises have duties under the Electricity at Work Regulations 1989 to keep electrical systems safe.

• Office electrical installation: Power and data to each desk through floor boxes, dado trunking or desk feeds, meeting room AV points, comms cabinets and data cabling (Cat6 is typical), and LED lighting with presence and daylight controls.
• Shops: Till points, display and window lighting, signage, security systems and back-of-house power.
• Restaurants and cafés: Circuits for commercial cooking equipment, refrigeration and extraction, often on a three-phase supply, and connecting the extraction to a gas interlock system where the kitchen uses gas.
• Industrial units and workshops: Three-phase power for machinery, isolators and emergency stops, industrial sockets and high-bay lighting.

A three-phase supply has three live conductors, each carrying alternating current that peaks at a different moment. In the UK it gives a typical 400 V between phases and 230 V between each phase and neutral, so it can run heavy equipment and spread large loads evenly. Commercial kitchens, machinery, larger air conditioning systems, lifts and multiple EV chargers often need it.

If your premises only have a single-phase supply, or the existing supply is too small, an upgrade is arranged with the distribution network operator: UK Power Networks across London. We assess the loads, prepare the information for the application, and install the switchgear and distribution on your side of the meter.

Larger premises usually have a main panel feeding sub-distribution boards for each floor, tenant or area. We install and replace distribution boards, label every circuit clearly, and make sure the protective devices are coordinated, so a fault trips only the circuit affected rather than the whole building.

For lighting, we replace old fluorescent fittings with LED panels and downlights, and add controls such as presence detection and daylight dimming. Light levels are matched to the task, whether that is an office desk, a shop display or a workshop bench.

There is no single fixed legal interval for most commercial premises, but the Electricity at Work Regulations 1989 require electrical systems to be maintained so they do not cause danger. Periodic inspection and testing, recorded on an Electrical Installation Condition Report (EICR), is the usual way to show this. Industry guidance commonly recommends an interval of up to five years for offices and shops, and shorter for premises with heavier use or harsher conditions. Insurers, landlords and leases often require one too. We carry out commercial inspections and maintenance through our electrical maintenance services, and any faults found are fixed through our electrical repair services.

• Opening hours: We plan work around your opening hours, phasing it so essential areas stay in use where possible.
• Planned shutdowns: When the power must be off, we agree the time with you in advance.
• CDM: On commercial projects the Construction (Design and Management) Regulations 2015 apply. We provide risk assessments and method statements, and coordinate with the principal contractor where there is one.
• Handover: Test results, certificates, circuit charts and any operating information for the building's records.