Which guideline must be followed for box installations in ceilings?

For box installations in ceilings, it's crucial that the box is rated for load and follows the manufacturer instructions. This requirement ensures that the box can safely support the weight of the fixtures and devices it will contain, which is particularly important in ceiling installations where there may be additional stresses due to hanging fixtures or the weight of multiple wiring connections.

Additionally, following manufacturer instructions is vital because boxes can have specific ratings and requirements that must be adhered to in order for them to maintain their integrity and safety standards. This means considering factors like the type of wiring, the total load being supported, and the way the box is mounted.

Ensuring that the box is appropriately rated protects against potential hazards such as overloads, short circuits, or even structural failures, making this guideline a fundamental safety aspect in ceiling installations.