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How this is calculated#

The tool checks a site for an all-in-one home battery. It reads AS/NZS 5139:2019 Section 4. It shows each rule as met, not met or not assessed. A distance you leave blank stays not assessed.

1. Place. It tests the location against the restricted places (Cl 4.2.2.2(a) to (k)). These are switchboard-restricted places, ceiling spaces, wall cavities, roofs unless deemed suitable, under stairways or access walkways, and escape routes. They also include habitable rooms of homes and hazardous areas.
2. Clearances. It compares your distances to an exit, a window or vent of a habitable room, and another appliance with the 600 mm rule. An item above the battery needs the 900 mm rule. In a corridor it checks the 1 m left for egress (Cl 4.2.2.1).
3. IP code. It wants IP2X indoors and IP23 outdoors (Cl 4.2.3.2). It compares each digit of your code.
4. Barrier. If the battery is on a wall to a habitable room, the wall must be non‑combustible (Cl 4.2.4.2). On a combustible wall, a non‑combustible barrier must reach 600 mm past each side, 900 mm above and down to the bottom.
5. Ceiling. If the ceiling is within 900 mm of the top, it must be non‑combustible for 600 mm past the battery (Cl 4.2.4.2).
6. Working space. It wants 600 mm on the working side, or 900 mm where panels reach the 230 V a.c. connections. It takes the maker's figure if that is larger (Cl 4.2.5).
7. Notes. It adds notes for a smoke alarm or fire panel detector (Cl 4.3.4, a "should") and for the maker's ventilation instructions (Cl 4.3.5).

Worked example#

• A garage wall that backs onto a bedroom. The tool gives 4 of 9 rules not met: the appliance clearance, the barrier, the ceiling and the working space. The hot water unit is 400 mm away. The barrier reaches 300 mm each side and 500 mm above. The ceiling is 700 mm over the battery. The working space is 700 mm.
• The same wall, fixed. The tool gives 9 of 9 rules met.

Limits#

• The tool covers a pre-assembled integrated BESS, Section 4. It does not assess other battery types. AmpSize does not hold Sections 5 and 6.
• AmpSize does not hold Amendment 1 (2025). Check it for changes.
• The tool tests the numbers you enter. It does not know your site. A roof needs a check that it is deemed suitable.
• It does not size the battery, the cable or the protection.

See also: Home battery location and clearances, Where can a home battery go, Solar battery size for a family home and the home battery tool.