These requirements cover electrically operated bells, sirens, horns, and similar audible signal devices, rated at 300 V or less, for fire-protective signalling service and intended for indoor and/or outdoor installation in accordance with CSA C22.1, Canadian Electrical Code, Part I, Safety Standard for Electrical Installations; and with CAN/ULC-S524, Installation of Fire Alarm Systems. Refer to CAN/ULC-S541, Speakers for Fire Alarm Systems, Including Accessories, for requirements pertaining to speakers. This standard also covers protective covers and accessories used with audible signals for fire alarm systems.