Read the product declaration
Check the product’s declared rating, the applicable test conditions and the manufacturer’s installation requirements. Glands, covers and openings can affect the protection provided by the assembled enclosure.
Consider the actual environment
Record the likely exposures and the equipment’s location. An enclosure classification is not a complete assessment of electrical protection, material durability or installation suitability.
Go to the source
IEC: introduction to IP ratings ↗
IET: installation standards and supporting guidance ↗
Check the equipment manufacturer’s instructions alongside the applicable installation requirements.