Surge Protection for ITS Cabinets

Traffic Signal Light

Overview of ITS Cabinet

The ITS cabinet hosts many components needed to operate local intersections, control signs and ramp meters. Reliability is necessary to ensure safety of drivers as well as pedestrains. With the growing demand and more equipment is being inserted into the traffic cabinet.

Threat to ITS Equipment

A "dark" intersection is the worst case scenerio for traffic signal cabinet. The interruption of power can be caused by transients which affect sensitive components within the cabinet. As a result of the disruption of power, drivers and pedestrains are placed at risk. Although traffic cabinets may use a SPD to protect the system, if the SPD is series installed using a internal fuse upstream for additonal protection, the SPD itself can ceate the loss of power.

Traffic at Main Intersection

The solution for ITS Cabinets

CITEL recommends the use of parallel installed SPDs, to ensure that once the SPD reaches the end of life scenerio it will not cause the power loss. This reduces the risk of the "dark" intersection. Surge protection plays a vital role in preserving the integrity of equipment and, more importantly, protecting the lives of personnel.

The installation of Surge Protective Devices (SPDs) within the ITS Cabinet is a measure that will not only extend the life of the circuit components but also increase the reliability of the system as a whole.

Selecting an SPD for ITS Cabinets

NEC/NFPA 70 require that Surge Protective Devices (SPDs) shall be UL1449 Listed . This means selecting a surge protector is easier than it has ever been. There are only a few choices available for SPDs that are UL Listed for any of the most commonly used surge standards including UL1449 5th Edition, UL497B, and UL497E, in addition, only UL Listed Surge Protectors are acceptable for facilities that will install a Lightning Protection System (LPS) certified to either NFPA 780 or the UL96A Master Label.

Recommended SPD for Main Service Panel

LocationEquipmentSystemSurge Protector Model#Link
Main Service Panelboard120/240Vac M50-120T-A M50-A

Recommended SPD for ITS Cabinet

LocationEquipmentSystemSurge Protector Model#Link
Power Panel120Vac DS72US-120S/G-F-ASSM

Cabinet Power Supply120Vac
Power Input
DS72US-120S/G DS72US-120S/G

Cabinet Power Supply24Vdc
Cabinet Power Supply Output
DS220S-24DC DS220S-24DC

Cabinet Power Supply12Vdc
Cabinet Power Supply Output
DS220S-12DC DS220S-24DC

Vehicle Detection CameraPOE+ MJ8-POE-C6A MJ8-C6A

Serial Interface Unit (SIU)24V DD25-24V

Contact us to develop a surge mitigation solution for your application

Where to purchase Citel SPD's


1ANSI C62.41, Low-Voltage AC Power Circuits
2UL1449 4th Edition, Surge Protective Devices
3UL1449 5th Edition, Surge Protective Devices
4UL497B, Surge Protectors for Data Lines and Fire-Alarm Circuits
5UL497E, Antenna Lead-in Conductors
6IEC 61643-11, Low-Voltage Surge Protective Devices - Part 11: Surge Protective Devices Connected To Low-Voltage Power Systems - Requirements And Test Methods
7IEC 61643-21, Low Voltage Surge Protective Devices - Part 21: Surge Protective Devices Connected To Telecommunications And Signalling Networks - Performance Requirements And Testing Methods
8IEC 61000-45, Electromagnetic Compatibility (EMC) - Part 4-5: Testing And Measurement Techniques - Surge Immunity Test
9CSA 22.2
10NOM-001-SCFI, Standard for Electronic Equipment
11NOM-003-SCFI, Electrical Products - Safety Requirements