Surge Arrestor Box for RS485 Network Lines

Industrial networks must operate reliably in harsh environments. Electrical over-stress transients caused by electrostatic discharge, switching of inductive loads, or lightning strikes, will corrupt data transmission and damage bus transceivers unless effective measures are taken to diminish transient impact.

These Surge Arrestor Boxes are available in four models:

  • Surge Arrestor Box – 1 channel – Model: SAB-04C
  • Surge Arrestor Box – 2 channel – Model: SAB-05
  • Surge Arrestor Box – 3 channel – Model: SAB-03
  • Surge Arrestor Box – 4 channel – Model: SAB-06

The device used in these product provides ESD, EFT and surge protection for data ports meeting IEC 61000-4-2 (ESD), IEC 61000-4-4 (EFT) and IEC 61000-4-5 (Surge) with Working Peak Reverse Voltage of 7 V or 12 V with Minimum Breakdown Voltage of 7.5 V or 13.3 V respectively.

The unit is suitable to be used for protection in the following areas such as network for industry control, RS422/485 interface, automatic control and instruments connection, telephone, modem and so on. And also it can be used in the sensor in electric current circuit and the protection for the second-usage instrument, preventing the protected device to be damaged from reaction and operation of the over-voltage and discharging of the static electricity.

Working: Under normal operating conditions, the Transient suppressor (TS) has high impedance to ground; ideally, it is an open circuit. The protection is accomplished by clamping the over-voltage from a transient to a voltage limit. This is done by the low impedance avalanche breakdown of a PN junction. When a transient voltage larger than the breakdown voltage of the TS is generated, the TS clamps the transient to a predetermined level that is less than the breakdown voltage of the devices that it is protecting. The transients are clamped instantaneously (< 1 ns) and the transient current is diverted away from the protected device to ground.


  • 400W Peak pulse power dissipation (tp = 8/20 μs)
  • Excellent clamping facility, multi-level over-voltage protection, low voltage limitation and little insertion loss.
  • Compact design and easy installation with DIN mount facility.