Dissimilar metal insulation

Dissimilar metal insulation means fitting an insulating layer wherever two different metals touch in a PV mounting system, for example an aluminium module frame fixed to a steel structure. It is a preventive action against galvanic corrosion, which is one cause of a defective mounting structure. Galvanic corrosion forms where different metals touch directly, and it often appears around the fastening screws. The sources say this insulation is required in humid and coastal areas, where the corrosion risk is highest. Corrosion of the frame or the mounting holes can be found by visual inspection of the mounting structure. This measure does not deal with other causes of mounting failure, such as under-designed wind or snow loads, weak anchorage or installation errors.

<!-- review notes

• sentence 4: support check: partial - Insulation required in humid and coastal areas is stated, but 'where the corrosion risk is highest' is not stated explicitly (only 'especially in humid or costal area').
• sentence 6: support check: partial - Passages list wind/snow load, anchorage and installation errors as separate causes, but never say insulation does not address them; this is an inference. -->