Electrical Installations for a modern prison facility

As a deviation from our usual consultancy services, we recently worked closely with a customer from Wiltshire, South West England, on the requirements for electrical installations in prison environments for a government contract.

Introduction
Designing electrical installations for prisons presents a uniquely challenging balance of safety, security, resilience, and efficiency. Such facilities are environments where the electrical infrastructure must do far more than supply power; it is intimately entwined with surveillance, access control, prisoner welfare, and emergency response. This case study examines the requirements against the Property Directorate STD/E/SPEC/018 for the electrical installations of a medium-security prison, highlighting key design considerations and challenges encountered.

Project Overview
The typical facility included accommodation blocks, administration and security offices, workshops, a medical wing, and communal spaces. The electrical installation was tasked with powering critical and non-critical systems, supporting advanced security features, and promoting energy efficiency, all while meeting rigorous safety standards.

Design Objectives and Requirements highlighted by the standard:

• Security and Safety: The foremost priority is to ensure that no part of the electrical system can be exploited as a means of escape, sabotage, or self-harm.
• Reliability and Redundancy: The system must remain operational during outages or emergencies, supporting essential services such as lighting, surveillance, and communication.
• Compliance: All installations must comply with national and local electrical and building codes, as well as strict prison standards.
• Scalability and Flexibility: The design should allow for future technological upgrades with minimal disruption.
• Energy Efficiency: The system should incorporate sustainable technologies to minimise operational costs and reduce its environmental footprint.

Project process
Initial Assessment:
The process began with a comprehensive desktop assessment, reviewing the types of equipment that the installation will be using.  A detailed risk analysis identified areas particularly vulnerable to electrical-related breaches or safety hazards, such as communal showers, cells, and workshops where tools are readily accessible.

Cabling and Conduit Selection:
All cabling within inmate-accessible areas should be routed through reinforced, tamper-proof conduits. In areas behind secure barriers, metal trunking provides additional protection. Low-smoke, zero-halogen cables are mandatory to minimise toxic fume risks in the event of fire. Colour-coded wiring further minimises risks of misconnection during maintenance.

Distribution Boards and Power Supply:
Distribution boards are strategically located within secure, staff-only service corridors and areas. Essential distribution boards feeding critical infrastructure were equipped with surge protection, uninterruptible power supplies (UPS), and automatic transfer switches for backup generators. All boards included lockable covers with tamper detection alarms.

Lighting Design:
Lighting was a focal point of the installation, with multi-level strategies for different areas:

• Cells and Dormitories: Vandal-resistant, tamper-proof fixtures with anti-ligature design. Lighting circuits included central override capability and automated dimming for night-time security.
• External Perimeter: High-intensity, motion-activated floodlights, with independent backup power to ensure perimeter visibility under all conditions.
• Communal Areas: LED fixtures controlled by occupancy sensors and integrated with the building management system for energy savings.

Emergency Power and Redundancy:
To meet reliability and safety mandates, the design also asks that the following be adequately provided for:

• Backup Generators: Sizing to support all critical systems, with automatic start and synchronisation.
• UPS: Short-term bridging for surveillance, communications, and access control until generator kick-in.
• Battery-Powered Emergency Lighting: Strategically placed along egress routes, cell blocks, and security posts.

Communication Infrastructure:
The integration of structured cabling (Cat6A and fibre optic) was specified, along with electrical layouts, to support data, voice, and video systems. All communication rooms need dedicated power supplies, UPS, and environmental controls.

Safety and Maintenance Considerations:
To reduce operational risks:

• All maintenance panels and switches were accessible only to authorised staff, with biometric authentication in sensitive areas.
• Comprehensive labelling, documentation, and as-built schematics were provided.
• Routine inspection schedules and remote monitoring were recommended.

Challenges
Mitigating Inmate Tampering - The most significant challenge was minimising the possibility of inmates tampering with electrical installations. All outlets in cells had to be specified with tamper-resistant covers, and plug sockets were to be limited in high-risk areas. Electrical equipment was selected for robustness, with fixtures designed to prevent access and concealment of contraband or use as weapons.

Balancing security with humanitarian concerns - While security dominated the design priorities, humane conditions are an essential part of the regulatory requirements. Adequate lighting, climate control, and communication were balanced against the need for control and surveillance. Anti-ligature and low-voltage features were essential in cells to reduce the risks of self-harm. Other requirements, such as the number of times a toilet can be flushed within a set period, are also essential. These types of requirements are strictly detailed in the STD/E/SPEC/018 publications, and the design shall meet or exceed those requirements.

Key lessons
Key takeaways from this project include:

• An early collaboration between electrical engineers, architects, and security experts is vital.
• Robust documentation, installation training, and clear maintenance protocols mitigate long-term operational risks.
• Every element exposed to inmate access must undergo rigorous security review, with anti-tamper and anti-ligature features as standard.

Conclusion
Desktop reviews for assessing electrical installations in such facilities are a multidisciplinary effort, where technical knowledge must consider the highest standards of security and humanitarian care as defined in the regulations. This case study demonstrates the importance of risk-based design, ensuring every aspect of the published standards is met. In addition to meeting the requirements for today, considering that technology is ever-evolving, we must ensure that prisons remain secure and adaptive environments with new technologies for both staff and inmates.