Electrical boxes are classified by multiple dimensions, not just shape. Common categories include box shape, device function, installation environment, gang size, and material. Shape helps identify where a box is used. Whether you're working on a residential, commercial, or industrial project, understanding the role of electrical boxes is crucial for ensuring safety and functionality. 305 (b) (3) (iii) Covers for boxes shall be permanently marked “HIGH VOLTAGE. 303 (e) (1) (ii). Electric signs and outline lighting are highly visible, safety-critical systems with unique code requirements for conductors, grounding, and equipment access. They are the focus of Article 600 of the National Electric Code.
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