Advantech BB-422HESP

RS-422/485 Surge Protector

  • Three stages of protection on every data line: 1) Gas discharge tube 2) Series resistor 3) Transient voltage suppressor
  • Protected signal ground connection
  • Rugged terminal block connections
  • Dedicated chassis ground lug


These three-stage surge protectors meet IEEE 1000-4-5: 1995 and IEEE C62.41-1991 recognized standards for premium surge protectors. It protects against lightning strikes, power surges, and other types of voltage disturbances with three stages of protection for each supported line: a gas discharge tube followed by a series resistor and finally a Transient Voltage Suppresser (TVS). Three RS-422/485 signals on terminal blocks are supported with a clamping voltage of approximately 6.8 Volts.

These surge protectors housed in a tough metal, panel mount case with a protected signal ground connection and dedicated chassis ground lug. In order to work properly, it is important to have a good connection between the #10 screws and a solid earth ground.

Part Number Interface Lines Protected Mounting
BB-422HESP RS-422/485 (3) RS-422/485 Panel Mount
BB-485HESP RS-422/485 (5) RS-422/485 Panel Mount
Serial Technology
Connectors, line 3 position terminal blocks
Connectors, equipment 3 position terminal blocks
Connectors, line 5 position terminal blocks
Connectors, equipment 5 position terminal blocks
Surge Suppression
Clamping Voltage - stage 1 72 VDC, minimum
108 VDC, maximum
Series Resistance - stage 2 2.7 Ohms
Clapming Voltage - stage 3 6.45 VDC, minimum
7.14 VDC, maximum
Clamping Time Less than 5 x10-9 seconds
Dimensions 11.4 x 8.4 x 4.6 cm (4.5 X 3.3 x 1.8 in)
Installation In-line
Weight 0.19 kg (6.7 oz)
Operating Temperature 0 to +70 °C (+32 to +185 °F)
Storage Temperature -40 to +85 °C (-40 to +185 °F)
Operating Humidity 0 to 95% Non-Condensing
Approvals / Certifications - 485HESP
FCC Part 15, CISPR, EN 55022: 2010 + AC:2011 Class A Emissions
EN 61000-6-1: 2007 Generic Standards for Residential, Commercial and Light Industrial Environments
EN 61000-4-5: 2006 Electrical Surges

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