PAS 63100: Best practice for residential solar battery storage placement

Product shot for Marley solar battery

With the installation of solar panels and solar batteries giving homeowners an easy and effective way to cut energy bills and reduce carbon emissions, the benefits of solar PV systems are clear. We can't, however, ignore that there is also concern about the fire risks associated with these installations - just like any electrical device. 

While these concerns are legitimate, the risk can also be mitigated with careful specification, high-quality products and, importantly, correct installation. That’s why PAS 63100:2024, Protection against fire of battery energy storage systems, has been created.

Understanding the fire risk associated with solar PV systems

It’s important to remember that the fire risk of solar PV systems is extremely low. Whilst this risk is minimal, there has been a huge increase in the number of homes built across the country with solar panel installations, (as well as on commercial and industrial buildings) and therefore statistically there has been a rise in the number of solar-related fires reported.

Poor installation practices are a common cause of fire. Commenting on the fire risk of solar PV systems, Gillian Perry, a major loss manager for insurance company Zurich, explained in a statement: “We’re seeing a small but growing number of claims for solar panels, the most worrying of which are electrical fires. While the vast majority of installers follow good practice, poorly or incorrectly fitted solar panels can increase the risk of blazes.”

Two of the main areas of concern regarding fire risk are the electrical connections and the placement of solar batteries. We’ve already covered the risk of electrical connections in this blog post, and the Marley ArcBox can help provide fire protection at these critical points. As far as solar battery placement is concerned, PAS 63100:2024 gives simple and effective advice for reducing fire risk in dwellings.

What is PAS 63100:2024?

PAS 63100:2024 is a publicly available specification (PAS) published in March 2024. It sets out guidance on the installation of solar batteries – also known as electrical battery energy storage systems (BESS) – to reduce fire risk in dwellings. It applies to domestic properties (under 200m2) using stationary secondary batteries for energy storage.
Since PAS 63100 is not a standard or regulation, there is no legal requirement to follow its recommendations. However, it does provide a best-practice approach and common-sense advice about where not to place solar battery storage systems – following its advice could save lives and protect property. 

PAS 63100 is also expected to be adopted by councils and local authorities as best practice, and it should, therefore, be used as a guide when installing solar batteries.

PAS 63100: the recommendations

The British Standards Institute (BSI) explains that PAS 63100 defines the fire safety requirements for the installation of solar batteries. These include:

  • Installation location
  • The physical requirements for battery units
  • Battery management and controls
  • Power conversion equipment (PCE)
  • Fault management and fail-to-safe operation of control and monitoring functions
  • Protection from impact, where relevant

The advice provided in PAS 63100 is intended to help installers manage the fire risks in dwellings associated with solar battery storage systems, preventing them from becoming a source of ignition and limiting the impact if a battery fire does occur.

While the benefits of following PAS 63100 are clear for property owners and building occupants, following the standard can also benefit installers by demonstrating their commitment to safety and helping them build a reputation for quality and reliable work.

Where to install solar batteries?

One of PAS 63100's main focus areas is its discussion of where to install solar batteries to reduce fire risk in dwellings. 
Paragraph 6.5.1 states that storage batteries should be installed outdoors, where practicable. This can be in an outbuilding not intended for habitation or detached or separated from a main wall with a minimum fire performance of REI 120 to BS EN 13501. Marley solar batteries are IP65 rated, they are dust and water-proof and suitable for outdoor installation. However we would still recommend additional protection from direct sunlight and extreme weather situations, a simple lean-to roof above the battery should be more than sufficient. 

If outdoor installation is not possible, a suitable indoor location should be well ventilated and have suitable fire protection. It should also be noted that paragraph 6.5.7 states that the maximum capacity for outdoor solar battery installations can be double that of indoor systems – 80kWh and 40kWh, respectively.

PAS 63100 states that solar batteries should not be installed in the following locations:

  • Rooms in which persons are intended to sleep
  • Routes used as a means of escape that are not defined as protected escape routes, including landings, staircases and corridors
  • Corridors, shafts, stairs or lobbies of protected escape routes
  • Firefighting lobbies, shafts or staircases
  • Storage cupboards, enclosures or spaces opening into rooms in which persons are intended to sleep
  • Outdoors (ground-mounted or wall-mounted in a suitable enclosure) within 1m of escape routes, doors, windows or ventilation ports
  • Voids, roof spaces or lofts
  • Within 2m of stored flammable materials and fuel storage tanks or cylinders
  • Cellars or basements that have no access to the outside of the building
Suitable interior locations for a solar battery might include utility rooms or purpose-built store cupboards. Paragraph 6.5.6 adds that when solar batteries are installed in locations that are not frequently visited, such as store cupboards, a smoke detector/alarm or multi-sensor fire detector/fire alarm that conforms to BS 5839-6 must be installed in that location.

As it currently stands, there are no legally binding regulations or standards that dictate the placement of solar batteries. But following the recommendations of PAS 63100 can help to reduce fire risk in dwellings. Even if it’s not law, it is likely to be a safety requirement for councils, social housing organisations and other stakeholders, so following its recommendations makes sense from every perspective.

Solar battery installation for new builds: design better from the start

We humans generally like things to be tidy and hidden from view unless we need them. This definitely goes for appliances that are important for our day-to-day lives but may not aesthetically fit with our interpretation of a cosy and comfortable home. Think refrigerators hidden behind faux cupboard doors and boiler cupboards to hide heating equipment.
This is also true for the various elements that go along with solar PV arrays. The solar panels themselves can’t be hidden from view (although, with panels as sleek and stylish as the Marley SolarTile, you wouldn’t really want to!) but the control systems, electrical units and the like? Your first instinct is probably to tuck them away somewhere and forget about them.

This is why PAS 63100 recommends suitable ventilation, fire detection and alarm systems for all installations.

Even the most aesthetically pleasing solar battery system is unlikely to seamlessly match the rest of the home’s decor, so the key – particularly for new builds – is to design better from the start, ensuring that installations and purpose-built enclosures fit in logically and attractively with their surroundings, while also meeting all best-practice recommendations. Designing an outdoor cupboard close to where the main electric board is for placement of the battery could be the ideal solution, similar to the gas and electric metre boxes that are built onto the side of the house. This solution should be designed in line with the PAS-63100 recommendation.

What about solar batteries for refurbishment projects?

While “design better from the start” is great for new builds, what about refurbishment projects – including those for councils and local authorities – where there are fewer options for solar battery placement?

The guidelines above are still relevant and out-buildings, garages and utility rooms may still be options to consider. Existing cupboards might also be suitable, as long as they adhere to the recommendations of PAS 63100. But it may also be necessary to build a special enclosure, either indoors or outdoors, for the solar batteries.

PAS 63100 advice, solar battery support and more from Marley

Here at Marley, we offer a comprehensive range of solar PV products, providing everything needed to create an attractive, user-friendly and safe home solar energy system

From the Marley SolarTile to solar batteries, inverters, electric vehicle charging systems and the ArcBox fire protection system, all of our products are designed for compatibility and to mitigate fire risk in dwellings. They can also be used as part of our complete roofing system with a 15-year warranty. You can learn more about our solar system by downloading our solar brochure.

If you’re not sure where to install solar batteries to meet the requirements of PAS 63100 – in either a new-build or refurbishment project – or if you have any other questions, please get in touch




Category: Solar