However, under strata law, the Owners Corporation has some control over the external appearance of the building. The OC, in theory, can prohibit items like solar panels (or political signage, or flags) being attached to the outside of the balcony, because they alter the look of the building. This is governed by model by-law 17, which says anything “not in keeping with the rest of the building” can be visible from outside the lot without consent.
But solar panels are sustainability infrastructure, and new amendments to the strata laws prohibit the use of appearance-based by-laws to prevent sustainability infrastructure being installed. This does not apply to heritage building, though. However, this prohibition is not absolute, so you should take care that any solar panels do not detract from the building’s appearance, so some rules about how and where the panels can be installed.