In what instance can a T-branch/splice be used in adding a fire alarm to existing power source?

Using a T-branch or splice to add a fire alarm to an existing power source is considered never acceptable due to safety concerns and regulations that govern electrical installations. Fire alarm systems are critical for ensuring the safety of life and property, and any modifications to their power sources must adhere to strict standards to prevent malfunctions or hazards.

The use of a T-branch or splice can introduce potential points of failure in the system, including increased resistance, possible overheating, or inadequate power supply to the fire alarm due to shared circuits. These risks are unacceptable in the context of a fire alarm system, which must operate reliably at all times.

Additionally, fire alarm installations are usually governed by specific codes and standards that mandate the use of dedicated power sources for fire detection and alarm systems. This further substantiates the necessity to avoid splice connections, ensuring that the alarm system maintains its integrity through a stable and dedicated power supply.