What is a Constant Live?

A Constant Live refers to the positive side of an electrical circuit that maintains a continuous flow of current, regardless of whether the connected device is switched on or off. It is essential for devices or systems that require uninterrupted power, such as security alarms, smoke detectors, or central heating controls.

In UK residential and building contexts, a Constant Live is a critical component of electrical systems. It ensures that essential safety and operational devices remain powered at all times. For example, in a home renovation or extension, Constant Live wiring is often used for smoke alarms to comply with Building Regulations Part B (Fire Safety) and Approved Document B. Similarly, it is used in central heating systems to maintain functionality even when the thermostat is off.

Practical Examples

1. Smoke Alarms: A Constant Live ensures smoke alarms remain operational 24/7, as required by Building Regulations Part B.
2. Security Systems: Burglar alarms and CCTV systems rely on Constant Live wiring to function continuously.
3. Central Heating Controls: Thermostats and boiler controls often use Constant Live to maintain settings and ensure readiness.

Synonym(s)

• Permanent Live

Related Terms

1. Switched Live: The positive side of a circuit that only carries current when a device is switched on.
2. Neutral Wire: The return path for electrical current, completing the circuit.
3. Earth Wire: A safety wire that provides a path for fault current to prevent electric shock.
4. Circuit Breaker: A device that protects electrical circuits from overload or short circuits.
5. RCD (Residual Current Device): A safety device that cuts off power in case of an electrical fault.
6. Part P of Building Regulations: Governs electrical safety in dwellings, including wiring practices.
7. Approved Document P: Provides guidance on electrical safety compliance in the UK.