John Street, Callaghan Square, Cardiff

Sector: Commercial & Office (Cat A)
Services: Full Electrical Installation

About this Project

Overview

John Street is a landmark 10-storey, 114,000 sq ft Grade A office development located in the heart of Callaghan Square, Cardiff’s premier commercial district. Designed to the highest contemporary standards, the building forms a key part of the city’s ongoing regeneration and offers high-quality, flexible office accommodation for large-scale corporate occupiers.

The all-electric building has been designed with sustainability, wellbeing and long-term operational efficiency at its core, targeting BREEAM ‘Excellent’, EPC ‘A’ and WELL ‘Silver’ accreditations. A rooftop terrace provides panoramic views across Cardiff city centre and Cardiff Bay, enhancing occupant wellbeing and amenity.

Lloyds Banking Group has committed to a 10-year lease of the entire building, with approximately 3,000 employees relocating to the new office, making John Street one of the most significant recent commercial lettings in South Wales.

Our Role

Evans Electrical Limited was appointed to deliver the full Cat A electrical installation for the development. Our works covered the complete electrical infrastructure and life safety systems required to support a modern, high-performance commercial office building, while aligning with the project’s ambitious sustainability and resilience objectives.

Working closely with the developer, design team and principal contractor, we coordinated our installation to suit the fast-paced city centre programme and ensured seamless integration with mechanical, BMS and specialist systems.

Scope of Works

Electrical Infrastructure & Resilience

Low voltage distribution systems
1000kVA standby / 909kVA prime-rated Perkins generator
Electronic systems protection
Electrical connections to mechanical plant
Earthing and bonding
Lightning protection system

Renewable & Low-Carbon Technologies

Photovoltaic installation:
- 39.6kWp system
- 99 no. panels rated at 400W each

Lighting Systems

General lighting installation throughout
Dimmable lighting systems to office areas
Emergency lighting systems
External and façade lighting

Small Power & Containment

Small power installations to Cat A standard
Full containment systems

Life Safety, Security & Access

Addressable fire alarm system
Intercom systems
Disabled refuge and emergency assistance alarm systems
Induction loop systems
Entry barrier system with ANPR and intercom

Specialist & Ancillary Systems

Electric heating to cycle store
12U wall-mounted data cabinet (600 x 600mm), including:
- PDU
- Incoming BT connection
- Data points for BMS panel and security PC

Project Delivery & Handover

Commissioning and testing of all electrical engineering services
Preparation and provision of working drawings
As-fitted drawings and comprehensive operation and maintenance manuals
Building services log book
12 months planned maintenance

Sustainability & Building Performance

Sustainability was fundamental to the design and delivery of John Street. The all-electric strategy, combined with on-site renewable generation via the photovoltaic array, supports the building’s targeted EPC ‘A’ rating and contributes to reduced operational carbon emissions.

High-efficiency lighting with intelligent dimming controls, resilient power infrastructure and robust life safety systems ensure long-term performance, flexibility and low running costs for the occupier, while supporting BREEAM and WELL certification requirements.

Outcome

The completed Cat A electrical installation at John Street provides a resilient, future-ready and highly sustainable platform for one of the UK’s largest banking groups. The building is now fully equipped to support thousands of occupants in a modern, healthy and energy-efficient working environment.

Evans Electrical Limited is proud to have worked with JR Smart Developers to deliver this flagship commercial office development in the centre of Cardiff.