Maintaining a reliable electrical supply is essential across commercial, industrial and infrastructure applications. However, achieving the right balance between performance, functionality and project requirements is equally important when specifying electrical equipment.
Recognising the need for dependable, intelligently designed solutions that deliver both technical capability and commercial value, Craig & Derricott is pleased to introduce Mercia-E, the latest addition to our Automatic Transfer Switch (ATS) portfolio.
Developed with practicality and value in mind, Mercia-E combines intelligent power source monitoring, automatic transfer functionality and Single-Line No-Break Bypass technology in a solution designed to meet the demands of modern electrical installations.
By bringing together essential performance, operational reliability and maintenance flexibility, Mercia-E provides a considered approach to power continuity, helping engineers, contractors and specifiers achieve the right solution for their applications.
Understanding Automatic Transfer Switches
An Automatic Transfer Switch is designed to monitor incoming electrical supplies and transfer a connected load from one source to another when required.
Typically, an ATS is connected to two power sources, which may include a utility supply, standby generator or another independent electrical supply.
Under normal operating conditions, the preferred source supplies the connected load.
If the ATS detects that the preferred source has failed or moved outside its configured operating parameters, the controller initiates a transfer to the alternative healthy supply.
When the preferred source becomes available again, the system can be configured to manage retransfer according to the required operating philosophy.
This functionality supports electrical resilience by providing an automatic response to changes in power source availability.
However, maintaining the ATS itself can introduce an additional challenge.
The Challenge: Maintaining an ATS Without Interrupting Supply
Like other electrical equipment, Automatic Transfer Switches require periodic inspection, testing and maintenance.
In conventional installations without a suitable bypass arrangement, taking an ATS out of service can require interruption of the connected load.
For organisations operating commercial buildings, industrial processes or critical infrastructure, planned interruptions can be difficult to accommodate.
They may require additional operational planning, temporary power arrangements or scheduled downtime.
The challenge is therefore not simply maintaining power during a source failure but also maintaining continuity when the switching equipment itself requires attention.
This is where bypass technology provides an important advantage.
Introducing Single-Line No-Break Bypass Technology
The new Mercia-E ATS incorporates a Single-Line No-Break Bypass arrangement designed to allow the ATS to be isolated for maintenance while maintaining the outgoing electrical supply.
The bypass arrangement provides an alternative supply path to the connected load, allowing the ATS to be removed from normal service without a planned interruption to the outgoing supply.
Once the bypass has been correctly established, the ATS can be isolated from both incoming sources and the connected load.
This allows authorised personnel to undertake inspection, maintenance or servicing while the load remains energised through the bypass.
The principal benefits include:
- Maintaining continuity of supply during ATS maintenance.
- Reducing the need for planned operational interruptions.
- Allowing the ATS to be isolated for servicing.
- Supporting more flexible maintenance scheduling.
- Helping reduce downtime associated with ATS inspection or replacement.
For installations where power continuity is important, this provides an additional level of operational flexibility.
Intelligent Source Monitoring and Automatic Transfer
At the heart of Mercia-E is a TP&N Automatic Transfer Switch incorporating an integrated controller.
The controller continuously monitors the voltage and frequency of two incoming AC power sources.
When a failure is detected, the system automatically transfers the connected load to the alternative healthy source, subject to the configured operating parameters.
Once normal supply conditions have been restored, the controller can be configured for either automatic or manual retransfer to the preferred source.
This flexibility allows the operating philosophy to be selected according to the requirements of the installation.
Designed for Connectivity and System Integration
Modern electrical installations increasingly rely on centralised monitoring and control systems to provide visibility of equipment status and operational performance.
Mercia-E incorporates a range of connection and communication options to support integration with wider electrical infrastructure.
Modbus RS485 Communication
Dedicated terminals provide connectivity for Modbus RS485 communication, allowing integration with compatible monitoring and control systems.
Generator Start/Run Connections
Generator control terminals are included to support connection to standby generation equipment.
Mimic Panel Connectivity
Mimic terminals allow connection to compatible Craig & Derricott single-way and multi-way mimic panels, providing remote indication of ATS operating status.
Volt-Free Status Contacts
Volt-free terminals enable connections to Building Management Systems, PLCs and other supervisory equipment for remote status indication.
Remote Manual Override
Dedicated terminals provide additional control flexibility where remote manual operation is required.
Together, these features help simplify system integration and provide greater visibility of the ATS operating condition.
Clear Local Indication
In addition to remote monitoring capabilities, Mercia-E incorporates LED indication mounted on the enclosure door.
This provides a convenient visual reference for personnel responsible for operating or maintaining the equipment.
Indication includes source availability, supply on load and bypass status.
By making key operating conditions immediately visible, local indication helps support efficient system monitoring and maintenance activities.
Robust Construction for Demanding Applications
Mercia-E is housed within a mild steel enclosure finished in Light Grey (RAL 7035).
The enclosure incorporates removable gland plates to support installation and cable management.
Internally, touch-safe barriers, shrouds and terminal covers help reduce the risk of accidental contact with energised conductors during authorised access.
Supporting Reliable Electrical Infrastructure
Electrical resilience requires careful consideration of performance, reliability, maintainability and overall project requirements.
While automatic power transfer helps address the immediate consequences of a source failure, maintenance accessibility and system visibility are equally important considerations.
Mercia-E has been developed to bring these capabilities together in a practical, commercially considered solution. Combining intelligent source monitoring, Single-Line No-Break Bypass technology and integrated communication capabilities, the range delivers the functionality required to support reliable electrical infrastructure without unnecessary complexity.
As part of Craig & Derricott’s expanding Automatic Transfer Switch portfolio, Mercia-E provides engineers, contractors and specifiers with greater choice when selecting a solution that balances technical performance with project requirements.
Discover Mercia-E
The new Mercia-E Automatic Transfer Switch range reflects Craig & Derricott’s continued focus on engineering practical solutions for modern electrical infrastructure.
Whether specifying equipment for a new installation or reviewing an existing power distribution arrangement, our technical team can help assess the requirements of your application.
Discover Mercia-E and explore a smarter approach to power continuity.
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