Fire Detector Loop Surge Protection 24V, SUG-SAP24V

SUG-SAP24V, overvoltage protection for 24V fire detector loops, dedicated for fire control panels.

SUG-SAP24V is a surge protection device designed to protect 24V sensor loops in fire alarm systems. It is dedicated for installations where the DC voltage and the variable component of the transmission signal do not exceed the maximum voltage of 32V.

Low internal resistance, low insertion capacitance, and the ability to transmit up to 3A have minimal impact on the system's operation.

The protection has a shielded wire terminal that eliminates the effects of surges through a GDT cutting element.

High-quality window terminals with high current load limit the risk of damage during large impulse shocks and temporary current overloads.

The product is designed for installation at the boundary between LPZ0 and LPZ1 zones or higher.


Fire alarm control panel protection diagram

Simplified internal diagram.


To ensure proper protection against surges, it is recommended to use devices at both ends of the cable and to properly ground them.


Example of a fire loop protection

Example of proper fire loop protection.



Short technical specification

Number of protected tracks
3 (2+ shield)
Input / output connector
Rated DC voltage (Un)
Maximum DC voltage (Uc)
Maximum AC voltage (Uc) 22V
Nominal current (In)
C1: Line-to-line discharge current 8/20µs (In)
C2: Line-to-ground discharge current 8/20µs (In) 10kA
C2: Maximum line-to-ground discharge current 8/20µs (Imax) 20kA
D1: Maximum lightning current 10/350µs (Iimp)
Protection level 1kV/μs (line-line) Up 40V DC
Series Resistance
~70mΩ / line
Dimensions 57 x 32 x 28 (mm)
Mounting Method Freestanding housing
Grounding Method
Housing Protection IP20
Operating Temperature -40ºC~80ºC