Which statement describes the use of 18/2 wiring in alarm installations?

• A. It is commonly used for power transformers and sirens
• B. It is never used for alarms
• C. It is used for data networks only
• D. It is for lighting circuits

Answer: (A)

The main idea here is that 18/2 is a low‑voltage two‑conductor cable used to power devices in an alarm system. In practice, this size is commonly chosen to deliver modest current to components such as a power transformer or a siren, especially for short runs where the current draw isn’t large. It’s not typically used for data networks, which require data-grade cables like Cat5e/Cat6, and it isn’t the standard for lighting circuits, which run on higher‑voltage 120V (usually with thicker gauges like 14/2 or 12/2). So this wiring is well-suited for powering low‑voltage alarm components, making the statement that it’s commonly used for power transformers and sirens the best fit.