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Batteries
Batteries · Fitting

Where can a home battery be installed?

Short answer

PAS 63100 says outdoors where practicable, for example an outside wall or detached garage. Batteries must not go in lofts, bedrooms, cupboards off bedrooms, hallways, landings or stairs, or basements without outside access. Outdoors they should be at least 1 metre from doors, windows and vents. Indoor spots need fire separation, ventilation and a linked smoke alarm.

Last checked 24 September 2026 · 5 sources

What should I know before deciding?

Max 20 kWh per enclosure; total 40 kWh or 80 kWh (outdoors/detached/REI 60 garage). IK10 protection near driveways/garages. PAS 63100 excludes homes >200 m2 and second-life batteries.

Where can a battery go under PAS 63100?

Outdoors wherever practicable. Indoors only where PAS 63100 does not exclude it, with ventilation to outside and REI 30 separation from excluded spaces. Excluded: bedrooms, escape-route landings, stairs and corridors, cupboards opening into bedrooms, lofts and voids, cellars without outside access, within 2 m of fuels, and outdoors within 1 m of doors, windows, vents or escape routes.

cl.6.5.1 outdoors preferred; detached outbuilding (or REI 120 separated) counts as outdoors. cl.6.5.5 list (a)-(i) is the full exclusion list. Living rooms, kitchens and under-stair cupboards are not named, but need REI 30 separation from escape routes plus ventilation to outdoors (6.5.3-6.5.4), so rarely workable.

Can a battery go on an outside wall or in the garage?

Yes - PAS 63100 prefers outdoors. Keep at least 1 m from doors, windows, vents and escape routes, and 2 m from fuel tanks. Don't compromise the wall's fire performance. Near driveways or in garages, batteries need IK10 impact protection or a barrier. Check the unit's IP rating and temperature range.

Tesla says Powerwall 3 is tested to IK08; installers may add barriers to meet PAS. Outdoor wall mounting may need planning consent in some cases (PAS 6.5.2 note).

Does an indoor battery need a 60-minute fire-rated room?

Not as a general rule. PAS 63100 requires REI 30 (30-minute) fire-resisting separation between an indoor battery location and the excluded spaces such as escape routes and bedrooms, with fire-stopped penetrations. REI 60 only applies to an attached garage or outbuilding to use the 80 kWh cap, and to battery enclosures with 4-8 cal/cm2 arc-flash energy.

cl.6.5.3 REI 30 to BS EN 13501 (30 min BS 476). cl.6.5.7(a)(3) REI 60 attached garage for 80 kWh. cl.6.3.2 Table 2 REI 60 enclosure for 4-8 cal/cm2.

What to do next

Ask the installer to show the proposed location, DNO route, backup arrangement and commissioning documents before work starts.

Sources

Last checked: 24 September 2026