Emergency lighting and signage must be powered by what to ensure operation during power loss?

• A. Must be powered by the grid only
• B. Must be powered by an independent source to remain functional during power loss
• C. Can be powered by any available device
• D. Not required if backup lighting exists

Answer: (B)

The key idea is that emergency lighting and exit signs must stay operational even when the building loses power, so they rely on an independent power source rather than the normal electrical feed. This independence ensures occupants can see and follow exits during a power outage.

That’s why the best answer is that emergency lighting and signage must be powered by an autonomous source—like a battery backup or a dedicated generator—so they automatically stay on for the required duration when the grid fails. These systems are designed to activate without human intervention and provide the mandated illumination long enough for safe egress.

Relying on the grid would mean the lights could go out the moment power is lost. Allowing any available device undermines reliability and doesn’t guarantee the required duration or automatic operation. And stating that it’s not required if backup lighting exists conflicts with the principle of having a self-contained, always-ready power source for life-safety illumination.