Planning and Preparation for De-Energisation of a Building to Change Electrical Infrastructure
- Ryan O'Toole
- Feb 15
- 4 min read
When undertaking a major electrical infrastructure upgrade, such as replacing a panel board, careful planning is crucial. A key part of this process is the de-energisation of the building to allow for the safe and efficient changeover of electrical components.
Without a structured approach, this process can cause significant operational disruptions to tenants and businesses within the premises. In this guide, we outline the essential steps to successfully plan and execute a de-energisation, covering key stakeholder discussions, necessary approvals, and coordination with the Distribution Network Operator (DNO).

Identifying and Engaging Key Stakeholders
The first step in planning a de-energisation is to identify and consult with all relevant stakeholders. Their input and cooperation are essential to ensure a smooth and efficient process.
1. The Tenant(s)
If the building is occupied by one or more tenants, they need to be informed well in advance. A temporary power outage can significantly impact business operations, IT systems, refrigeration, security measures, and more. Key considerations include:
Providing a clear schedule for when power will be turned off and back on.
Discussing temporary power solutions if required (e.g., backup generators).
Minimising downtime and ensuring the works are completed within the agreed window.
Ensuring the tenants inform their staff and prepare for the outage.
2. The Landlord
The landlord plays a critical role in authorising the de-energisation process and ensuring the legal and safety aspects are in order. The landlord may need to:
Approve the planned electrical work.
Coordinate with property managers and third-party service providers.
Ensure compliance with any lease agreements regarding building services.
3. The Management Agent
If a management agent is responsible for the property, they will act as an intermediary between the landlord, tenants, and contractors. Their role includes:
Facilitating communication between all parties.
Ensuring building regulations and safety requirements are adhered to.
Approving contractor access and arranging permits if required.
Assisting with tenant notifications and queries.
4. Third-Party Estate Managers
For buildings within a larger commercial estate, third-party estate managers may also need to be involved. They may be responsible for:
Coordinating with security teams to grant contractor access.
Managing fire alarms, emergency lighting, and access control systems affected by the power shutdown.
Ensuring compliance with any estate-wide policies.
5. The Distribution Network Operator (DNO)
The DNO (such as UK Power Networks, Western Power Distribution, or Northern Powergrid) must be consulted when disconnecting and reconnecting the power supply. They are responsible for:
Approving and scheduling the de-energisation.
Sending out an authorised engineer to isolate the supply.
Ensuring compliance with BS 7671 wiring regulations.
Reinstating power once the infrastructure upgrade is complete.
Step-by-Step Process for Planning a De-Energisation
Once all stakeholders are identified and engaged, the following steps ensure a structured and efficient process:
1. Conduct a Site Survey
Before any work is undertaken, a full site survey should be carried out to assess:
The existing electrical infrastructure.
The scope of work required for the panel board replacement.
Access requirements for engineers and DNO operatives.
Potential risks and contingency planning.
2. Develop a Shutdown Schedule
A carefully planned shutdown schedule should be created, detailing:
The proposed date and time of the de-energisation.
The estimated duration of power outage.
Work phases and milestones.
Testing and commissioning time before re-energisation.
3. Obtain Approvals and Permits
Before work begins, the necessary permits and approvals should be secured. These may include:
Permission from the landlord and management agents.
Authorisation from the DNO for power isolation.
Temporary work permits for contractors and engineers.
Risk assessments and method statements (RAMS) for compliance with health and safety regulations.
4. Notify Tenants and Stakeholders
Clear and timely communication with tenants and stakeholders is essential. Notifications should include:
Exact shutdown date and time.
Expected downtime duration.
Mitigation measures (e.g., generator backup, staggered shutdowns).
Emergency contact details for queries.
5. Arrange Temporary Power Solutions (If Needed)
For businesses or services that cannot afford downtime, alternative power solutions should be arranged, such as:
Temporary generators.
Uninterruptible Power Supply (UPS) systems for critical loads.
Scheduling the work outside of business hours.
6. Managing Building Services During Power Outage
When power is cut off, several building services will be affected, requiring proactive planning:
Access Control Systems: Electronic access systems will go offline, requiring manual entry procedures or temporary power sources.
Security Systems & CCTV: Ensure temporary battery backup or arrange for on-site security personnel to maintain surveillance.
Fire Alarm Systems: Fire alarms may be disabled, necessitating temporary solutions like fire marshals or battery-operated alarms with wireless remote monitoring.
Redcare Communication: If Redcare is impacted, backup solutions such as alternative monitoring systems should be deployed.
IT and UPS Shutdown: IT systems should be correctly shut down to prevent data loss, and UPS systems should be monitored for longevity.
Temporary IP VOIP Lines: External IP-based phone lines should be arranged if needed to maintain tenant communications during the outage.
Isolation of Generating Plant: Any on-site generators should be properly isolated to ensure safety during de-energisation.
ATS Functionality Testing: Once re-energisation takes place, Automatic Transfer Switches (ATS) must be tested to confirm they function correctly in case of future power outages.
Insurance Requirements: Ensure compliance with building insurance policies by maintaining security, monitoring, and emergency alarm systems during the outage to protect the asset and its contents.
7. Coordinate On-Site Logistics
Ensuring smooth operations on the day of de-energisation requires:
On-site access for DNO engineers and electrical contractors.
Secure storage for tools, equipment, and replacement parts.
Proper safety measures, including lock-out/tag-out (LOTO) procedures.
Coordination with fire and security teams to prevent alarms from triggering unnecessarily.
8. Execute the Changeover and Re-Energisation
With all approvals and preparations in place, the electrical changeover can proceed:
DNO isolates power and confirms a safe work environment.
The old panel board is disconnected and removed.
The new panel board is installed and wired in accordance with BS 7671 standards.
Testing and verification are carried out before DNO restores power.
A final safety check ensures that all systems function as expected.
9. Post-Installation Testing and Certification
After the installation, the following steps should be undertaken:
Full testing and commissioning of the electrical system.
Certification of the installation in compliance with BS 7671.
Submission of test reports and compliance documentation.
Final notification to tenants confirming completion of works.
Final Thoughts
De-energisation of a building for an electrical infrastructure upgrade is a complex process requiring detailed planning, coordination, and stakeholder engagement. By following these structured steps, Mech-Elec Building Services ensures that such projects are delivered efficiently, safely, and with minimal disruption.
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