Which of the following describes a characteristic of both watertight and weatherproof constructions?

The characteristic that describes both watertight and weatherproof constructions is that they ensure functionality in adverse conditions. This means that these constructions are specifically designed to protect electrical equipment from the effects of moisture, rain, snow, and other environmental factors.

Watertight construction prevents the ingress of water under certain conditions, thereby safeguarding the electrical components from water-related damage. Similarly, weatherproof construction defends against a broader range of environmental conditions, including varying temperatures, humidity, and other weather phenomena. Together, these characteristics allow electrical installations to function reliably regardless of the weather conditions they are exposed to, which is crucial for maintaining safety and performance.

The other options do not accurately reflect the shared characteristics of watertight and weatherproof constructions. For instance, while preventing physical damage may be a concern, it is not a defining feature of either construction type. Nor are both designed for indoor use only, as both can be necessary for outdoor installations as well. Lastly, specific temperature ratings may apply to certain fixtures but do not universally characterize watertight and weatherproof designs.