14 CFR §25.1721

1. (a)No cargo or baggage compartment may contain any EWIS whose damage or failure may affect safe operation, unless the EWIS is protected so that:
   1. (1)It cannot be damaged by movement of cargo or baggage in the compartment.
   2. (2)Its breakage or failure will not create a fire hazard.
2. (b)EWIS must be designed and installed to minimize damage and risk of damage to EWIS by movement of people in the airplane during all phases of flight, maintenance, and servicing.
3. (c)EWIS must be designed and installed to minimize damage and risk of damage to EWIS by items carried onto the aircraft by passengers or cabin crew.