What type of power is commonly used by CCTV cameras in terms of alternating current?

CCTV cameras frequently utilize 24 VAC (volts alternating current) as a standard power supply. One of the key reasons for this is that 24 VAC is commonly found in commercial security systems, allowing for a balance between adequate power supply and lower voltage safety. This lower voltage is beneficial as it reduces the risk of electric shock, making it safer for installations in public and uncontrolled environments.

Using 24 VAC also allows for longer cable runs without significant voltage drop, which can be crucial in larger installations where cameras are situated far from power sources. The use of 24 VAC is generally standard in both indoor and outdoor camera installations, thus ensuring compatibility with a wide range of accessories and equipment designed to work within this voltage range.

In contrast, the other voltage options—110 VAC, 120 VAC, and 240 VAC—are higher voltages typically associated with standard residential or commercial electrical systems but are not commonly used to power CCTV cameras directly due to the associated safety risks and the need for additional step-down transformers or power supplies to convert these higher voltages to a lower and safer level suitable for camera operation.