SIEL Energy Systems Ltd

Siel House
Draycott Business Park
GL11 5DQ
United Kingdom

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We have more than 20 years experience as a specialist provider of power protection systems, including central power systems (CPS), static transfer switches (STS) and uninterruptible power systems (UPS) for mission critical applications, and we are one of the UK’s leading power protection providers. As well as continued growth in the power protection field, we have also expanded our capabilities within the renewable energy sector, and we now offer photovoltaic (PV) and wind turbine converters. Our ongoing commitment to providing the highest standards of product quality and reliability is reflected in the excellent reputation our products have gained, as well as the repeat business we are pleased to enjoy from our valued clients. As the UK subsidiary of SIEL SpA, all members of our highly trained UK based team of after-sales and service engineers have CSCS and CCNSG (Safety Passport) cards as well as first aid training. We maintain a comprehensive stock of UK spares for current as well as legacy production products. In addition to our power protection and renewable energy products and solutions, we also offer a wide range of services, including: 24/7 emergency call-out facility Battery maintenance & testing Battery replacement and disposal of old batteries Installation, system start-up and commissioning Load bank testing Preventative maintenance contracts and remote monitoring Site surveys Witness testing

Uninterruptible Power Systems:

We offer an extensive range of single, three-phase and modular uninterruptible power systems.

The output power range of our single/single phase UPS systems is 400 VA to 20,000 VA depending on the system. These UPS systems range from units designed to protect computer systems and networks in homes and small offices, to those suitable for medium-sized networks and computer systems, through to the robust and customisable Multi-Plus UPS with advanced features such as remote emergency shutdown.

Three/single phase systems, with output power ranges between 3000 VA and 20,000 VA, include the Dialog Dual TM and Power Dialog 3 for protecting medium and large-sized servers and networks, and the Safepower Evo with output transformer.

Our three/three phase systems feature output power ranges from 10.0 kVA up to 1000 kVA. Our modular UPS systems offer scalable architecture with hot swap capabilities.

Transfer Switches:

We offer two types of transfer switches that provide enhanced system availability through the transfer of critical loads from one source to another: Automatic Transfer Switches (ATS) and Static Transfer Switches (STS).

Automatic transfer switches use electromechanical switching, while static transfer switches utilise solid state technology. This means the transfer time is faster with STS systems than with ATS systems, making STS more suited to sensitive applications. We offer a rack STS as well as the Exchange series of three-phase static transfer systems which can be configured for critical applications and infrastructures such as data centres.

Central Power Systems:

Our range of central power systems, also known as AC central battery systems or static inverters, encompasses single/single phase, three/single phase, and three/three phase systems, with ratings ranging from 2.0 kVA up to 200 kVA.

These power systems provide an independent energy supply, and are often used with emergency lighting systems and other equipment essential to safety. Batteries provide backup power, usually 1 or 3 hours.

Our central power systems are configurable with several operational modes, and can exceed the requirements of a standard UPS as defined in BS EN 50171:2001.

Frequency Converters

Our extensive range of static frequency converters covers a wide variety of civil and military applications. We offer 50/60 Hz, 60/50 Hz and 50/400 Hz static frequency converters, with output power ranging from 1 kVA up to 600 kVA. These converters can be configured to suit your application’s specific requirements.

Renewable Energy Systems:

We offer a full range of renewable energy systems to include solar (PV) and wind turbine converters.

We have a wealth of experience in the PV Solar energy sector and have installed numerous systems in Europe. We offer SOLEIL single phase photovoltaic converters and three phase PV, LV PV and MV converters as well as a containerised PV system for large scale installations.

Our WINDWAVE wind turbine power converters provide direct connection to the grid, with three phase outputs ranging from 10 kW to 125 kW. The single enclosure system has a PWM IGBT inverter bridge and galvanic isolation transformer with harmonic filters.

Connectivity Solutions

While a variety of communications interfaces for remote status indication are included as standard in all our systems, we can also provide other interfaces and connectivity levels to meet site or client specifications, such as:

  • Complete management over a local access network via TCP/IP, HTTP or SNMP protocols
  • RS 232 / RS 485 ports
  • Modbus
  • Automatic shutdown software that safely powers down servers and computers protected
    by UPS
  • Remote monitoring panel with UPS status and interrogation visual indication
  • 24/7 remote monitoring service with dedicated response times from our facility, as part of a comprehensive maintenance agreement

External Manual Bypass Systems

An External Manual Bypass System (EMBS) enables you to manually initiate the transfer of the electrical load to the mains supply from the UPS. The no break transfer is free from interruption and isolates the system for maintenance, testing, servicing or repair.

We offer wall mounted, 19 inch rack mounted or freestanding EMBS units for both parallel and single systems.

EMBS key features and options include:

  • All switchgear and terminations within a self-contained unit
  • Optional electrical or ‘Castell’ interlocking for prevention of inadvertent switching
  • IP ratings options as required to suit the physical environment
  • Optional glass door
  • Optional client-specified internal separation forms of construction in accordance with BS EN 60439-1
  • Spare ways provided for future upgrades
  • Cable entry on bottom, top or side, including dedicated cable ways if required
  • Optional external load bank connection

Legacy Products

As we continually evolve and update our product range with new technology, we provide ongoing support, maintenance and spare part availability for discontinued products. The following products have been discontinued:

  • Uninterruptible Power Systems:
  • TR2000*
  • TR3000*
  • Emergency Lighting Systems:

* Spares availability is limited for products with an asterisk.

Turnkey Solutions

At SIEL we have a proven track record of delivering turnkey power solutions on time and within budget. From initial consultation right through to final installation, we offer a high quality, fully transparent service that is tailored to your needs. We take into account all of the electrical, environmental and installation considerations in order to deliver a first class power solution. As a client you will benefit from years of practical experience and a single point of contact which ensures a fully coordinated installation – with the very minimum amount of disruption to your business operations.


All of our systems are built to last, but to ensure their ongoing performance, we recommend that they undergo regular preventative maintenance inspections. We’re able to provide a number of preventative maintenance agreements, which, depending on the level of cover chosen, will include some or all of the following services:

  • Scheduled maintenance visits
  • Emergency call out within agreed response times
  • Labour/travel inclusive fixed cost
  • 24/7 emergency contact with our engineers
  • 24/7 remote monitoring
  • Spare parts cover outside of equipment warranty
  • Battery impedance testing
  • On-site spares kit

Other specialist services include thermal imaging, load bank testing, and black building testing attendance. For more information, please visit our website or get in touch directly.

Battery Maintenance Replacement

Any UPS, CPS or DC system relies on its batteries as the source of backup power in the event of a mains disruption. If even a single cell within an installation fails, the whole system could be compromised. That’s why we highly recommend a maintenance regime that includes impedance testing undertaken on a regular basis. This will allow any changes in the internal electrical characteristics to be recognised at an early stage, allowing corrective measures to be taken either by replacing individual blocks or the entire system. If you would like to find out more about our battery maintenance and replacement services, please head directly to the SIEL website.


iDialog is an Uninterruptible Power Supply (UPS) designed to protect PCs and critical peripherals in home and small office environments. It is easy to install and offers powerful, economic protection for a range of devices, including PCs, Media Centres, VoIP equipment, TVs, Home Cinemas, DVD Readers and Writers, Modems, Routers, Satellite and Digital Terrestrial receivers and other small household appliances.  iDialog comes with monitoring and shutdown software compatible with most of the common operating systems, including Windows Vista, 2003, XP, 2000, Me and 98, Linux, Mac OSX and Sun Solaris. A compact and ergonomic design allows the iDialog UPS to placed on top of a desk or in another convenient location; a front LCD display provides UPS status, load and battery information.


netDialog is an Uninterruptible Power Supply designed to protect personal computers, PoS terminals, key phone systems and small to medium size file servers. It is the ideal UPS solution for small office hardware. netDialog uses digital Line Interactive (VI) technology; the load is powered from the mains through an Automatic Voltage Stabiliser (AVS) and an EMI filter, stabilising brownout, sag and surge and suppressing spikes and transients. Should the mains supply fail, the load is powered by the inverter with a pseudo sinewave that provides sufficient runtime for safe shutdown using the supplied software. netDialog is available in 800, 1000, 1500, 2000VA models.

Dialog Vision

Dialog Vision is ideal for the power protection of sensitive loads within small-to-medium sized networks. Like netDialog it uses digital sinewave protection to allow safe shutdown in the event of a mains failure, however this UPS has an easy-view front LCD that provides a wealth of operating status information. It can also be fitted with a battery extension pack to extend the internal battery runtime to several hours. Dialog Vision has an Automatic Voltage Regulator and EMI filters to protect against brownout, sag, surge, spikes and transients. It is available in slim-line rack mount and tower formats from 500VA to 3.0kVA.

Multi Plus

Multi Plus is our most advanced UPS. It offers the latest power protection technologies, with a high input power factor, high operating efficiency and advanced battery management. Multi Plus has been designed for easy installation, especially on sites with limited power capacity and harmonic compatibility problems. It features a large front panel graphical display that provides real-time measurements, operating status and alarm conditions – in five different languages. It also has RS232 and USB serial ports for PC connectivity. You can find out more about this feature-rich UPS by visiting SIEL Energy Systems online.

Transfer Switches: Automatic Transfer Switch - ATS

Multi Switch is an intelligent Automatic Transfer Switch (ATS) that is powered from two independent sources. This gives your electronic appliances power protection on standby should one source fail suddenly. Its output sockets are capable of accommodating up to eight separately connected network devices. Multi Switch is ideal for complex computer and VoIP networks that require maximum uptime. Features include an LCD display for measurement, alarm and status information, output socket control and a remote monitoring serial interface (SNMP or RS232).

MTR Rack Mount STS

Our 19” rack-mount Static Transfer Switch (STS) facilitates automatic switching between two independent single phase power supplies to ensure a ‘high availability’ power supply for network and telecom applications. A rotary switch provides selection of the priority source, and a manual bypass switch allows for the complete isolation and removal of the power module for service or replacement whilst maintaining the supply to the critical load.  The STS features a synoptic diagram with LED indication of the system status and power flow, and has dual hard-wired input supply connections (A & B Source) at the rear of the unit. Load connection is via 10 x IEC rear connections.

Uninterruptible Power Systems: Single/single phase

SIEL Energy Systems offers a comprehensive range of uninterruptible power systems including single/single phase systems such as the iDialog 400VA – 800VA. The iDialog has been specifically designed to provide protection for PCs and critical peripherals whether in the home or in the small office environment. Our single phase power systems provide protection across a range of equipment including televisions, home cinemas, small household appliances, modems, routers and many more. Our range of single phase power systems includes reliable and durable units such as netDialog, Dialog Vision, SENTINEL Pro, SENTINEL Dual Low Power and the SENTINEL Dual High Power. Visit the SIEL Energy Systems website to view full specifications on our range of single phase uninterruptible power systems.

Uninterruptible Power Systems: Three/single phase

Our range of three/single phase uninterruptible power supply units includes the SENTINEL Dual High Power model. This model has been designed to provide power protection across a range of IT equipment including medium sized file servers, telephone switches and communication cabinets. The SENTINEL Dual High Power model is ideal for those looking for a flexible multiple operating format power system for computers and telecommunication systems. Our three/single phase models such as the SENTINEL range are easy to install and use, and include a number of operating systems such as economy, smart active, emergency and frequency conversion 50 or 60Hz. Full specifications of our entire uninterruptible power supply (UPS) range can be viewed at the SIEL Energy Systems website.

Transfer Switches: 19" Rack Static Transfer Switch - STS

Our MTR 19” rack mount static transfer switch is a 16 – 32A single phase unit that facilitates fully automatic switching between two independent single phase power supplies. This is the ideal solution to provide a high availability power supply for network and telecom applications. This model comes with a synoptic diagram boasting LED indication of both the system status and the power flow. Other features include a rotary switch that allows for the selection of the priority source as well as an integrated manual bypass facility. The isolation and the removal of the power module for either service or replacement while maintaining supply to the critical load is permitted via the manual bypass switch.

Renewable Energy Systems: Solar (PV) - SOLEIL Range

SIEL Energy Systems offers a range of SOLEIL photovoltaic (solar) converters including single, three phased and containerised PV systems. Units such as our 3 phase PV converter are rated 10kWp and specifically designed for grid connected applications and offer efficiency levels of up to 96%. Our units are extremely easy to install and are lightweight in design and very compact. We also offer the SOLEIL containerised PV system, which is the ideal solution for large scale grid connected solar farms, parks and commercial rooftop installations. Power ratings vary dependent on the model and full specifications of our entire range of SOLEIL solar converters can found at the SIEL Energy Systems website.

Renewable Energy Systems: Wind Turbine Converters

Our Soleil WINDWAVE power converters are the ideal solution for direct grid connection offering three phase outputs from 10 – 125kW. Features of this system include a PWM-IGBT inverter bridge galvanic isolation transformer as well harmonic reduction via inductive and capacitive filters. Transformer efficiency levels for the Windwave power converters are typically in excess of 98.5%. All components of this system are housed within one enclosure and all controls such as synchronisation, protection and current control are available through a diversity of control logics. Full specifications of our Windwave power converters are available at the SIEL Energy Systems website.

Contact Us

SIEL Energy Systems has been an established UK provider of power protection systems for over two decades. We are based in Siel House, Draycott Business Park, Cam in Gloucestershire. We can be contacted by telephone, fax or by email, details of which are available at our website. Our website also contains an enquiry form for requests, purchasing and information. Once we have assessed your details we will contact you as soon as possible. Please do not hesitate to contact one of our experienced advisors for information on any of the SIEL Energy Systems range of products and services.



Registration Number: 02661321
VAT Number: GB576 2454 20
Registered at Companies House:7 November, 1991 (30 years and 1 month ago)
No of Employees: n/a
Annual Turnover: n/a
Company Type:
  • Manufacturer
  • Distributor
  • Service Providers

Opening Times

Monday 09:00 AM - 05:30 PM
Tuesday 09:00 AM - 05:30 PM
Wednesday 09:00 AM - 05:30 PM
Thursday 09:00 AM - 05:30 PM
Friday 09:00 AM - 05:30 PM
Saturday Closed
Sunday Closed

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Additional Information

Brand & Trade Names

  • CELLWATCH ® BMS provides continuous and intelligent monitoring of your batteries. Battery condition is measured and data collected automatically for evaluation and trend analysis. Any potential problems are identified and notified in real time.
  • GREENPOINT For single phase applications, with power output in the range of 1kVA to 20kVA.
  • LOPOWER TM For 3- phase input and single phase output applications, with power output in the range of 10kVA to 20kVA.
  • LOPOWER TT For 3- phase input and output applications, with power output in the range of 10kVA to 30kVA.
  • SAFEPOWER Evo For 3-phase input and output applications, with power output in the range of 20kVA to 1MVA in a single module.

Company Certifications

ISO 9001:2015 - Quality management systems – Requirements

Financial Information

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