DC isolators for photovoltaic systems (FB 68)
BRE (Building Research Establishment) is an independent, research-based consultancy, testing and training organisation, operating in the built environment and associated industries.
On 7 October 2014, BRE published DC isolators for photovoltaic systems (FB 68), by Steve Pester.
Photovoltaic (PV) power systems are becoming increasingly commonplace. But rapid expansion of the market brings with it a need to be vigilant in the maintenance of standards. Misunderstanding the details of the technology can prove dangerous.
DC isolators are a critical component for the safe design and installation of PV systems, and were made mandatory by the Wiring Regulations (BS 7671). But a lack of understanding has led to a few incidents of fire in UK installations. In most cases they are safe and reliable, but if they are incorrectly specified or installed isolators can cause fires. This 28 page guide explains the key points that should be taken into account when specifying DC isolators, including the standards and certifications required.
The guide describes the purpose, functions and features of isolators on PV systems as well as some of the available products. It explains some of the issues found in the field, with a rogues’ gallery of examples and reviews the relevant standards and guidance currently available
The contents of the guide include:
- Introduction.
- What is an isolator?
- Current issues and rogues’ gallery.
- AC and DC electricity.
- Typical PV systems.
- Types of DC isolator on the market.
- Specifying DC isolators for PV systems.
- Standards and certifications.
- Conclusions and recommendations.
- Appendix: Utilisation categories.
- References and further reading.
[edit] Find out more
[edit] Related articles on Designing Buildings Wiki
- Battery energy storage systems with grid-connected solar photovoltaics BR 514.
- BRE articles on Designing Buildings Wiki.
- BRE Buzz articles on Designing Buildings Wiki.
- BRE National Solar Centre.
- BRE photovoltaic certification scheme.
- Building Research Establishment.
- Code of practice for grid connected solar photovoltaic systems.
- Future of electricity in domestic buildings.
- Large scale solar thermal energy.
- Microgeneration.
- Micro-grid.
- Pavegen.
- PV inverter.
- Solar photovoltaics.
- Solar thermal systems.
- The Future of Electricity in Domestic Buildings.
Featured articles and news
ECA, JIB and JTL back Fabian Society call to invest in skills for a stronger built environment workforce.
Women's Contributions to the Built Environment.
Calls for the delayed Circular Economy Strategy
Over 50 leading businesses, trade associations and professional bodies, including CIAT, and UKGBC sign open letter.
The future workforce: culture change and skill
Under the spotlight at UK Construction Week London.
A landmark moment for postmodern heritage.
A safe energy transition – ECA launches a new Charter
Practical policy actions to speed up low carbon adoption while maintaining installation safety and competency.
Frank Duffy: Researcher and Practitioner
Reflections on achievements and relevance to the wider research and practice communities.
The 2026 Compliance Landscape: Fire doors
Why 'Business as Usual' is a Liability.
Cutting construction carbon footprint by caring for soil
Is construction neglecting one of the planet’s most powerful carbon stores and one of our greatest natural climate allies.
ARCHITECTURE: How's it progressing?
Archiblogger posing questions of a historical and contextual nature.
The roofscape of Hampstead Garden Suburb
Residents, architects and roofers need to understand detailing.
Homes, landlords. tenants and the new housing standards
What will it all mean?
The Architectural Technology podcast: Where it's AT
Catch-up on the latest episodes.
Edmundson Apprentice of the Year award 2026
Entries now open for this Electrical Contractors' Association award.
Traditional blue-grey slate from one of the oldest and largest UK slate quarries down in Cornwall.
There are plenty of sources with the potential to be redeveloped.
Change of use legislation breaths new life into buildings
A run down on Class MA of the General Permitted Development Order.
Solar generation in the historic environment
Success requires understanding each site in detail.
Comments