Traffic Signal Light

Overview of NEMA TS 1 Cabinet

NEMA TS 1 cabinet, first released in 1975 are still widely presently to control our intersections accross the country. These traffic cabinet host many components needed to operate local intersections, control signs and ramp meters. Reliability is necessary to ensure safety of drivers as well as pedestrians.

Replaced by NEMA TS 2 standard released in 1989, NEMA TS 1 are not deployed anymore but are mainly retrofitted with upgraded equipment when possible to save cost to DOTs and munucipalities.

Threat to NEMA TS 1 Cabinet

A "dark" intersection is the worst case scenario 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 or proper fnctionning of the internal sensitive electronics, drivers and pedestrians are placed at hiugh safety risk. Although traffic cabinets may use an SPD to protect the system, the majority of the surge solutions presenly deployed in the TS 1 traffic cabinets creates a disprution of that power supply continuity to the cabinet are are safety concern.

NEMA TS 1 Cabinet

The solution for NEMA TS 1 Cabinets

CITEL recommends the use of parallel installed SPDs, to ensure that power is being supplied to the traffic equipment in all conditions. This reduces the risk of the "dark" intersection, without any signalization, main cause for accident. 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 traffic controller cabinets 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 NEMA TS 1 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

Location	Equipment	System	Surge Protector Model#	Link
	Main Service Pedestal	120/240Vac	M50-120T-A

Recommended SPD for TS 1 Cabinet

Location	Equipment	System	Surge Protector Model#	Link
	Power Panel	120Vac	DS72US-120S/G-F-ASSM
	Cabinet Power Supply	120Vac Power Input	DS72US-120S/G
	Cabinet Power Supply	24Vdc Cabinet Power Supply Output	DS220S-24DC
	Cabinet Power Supply	12Vdc Cabinet Power Supply Output	DS220S-12DC
	Vehicle Detection Camera	POE+	MJ8-POE-C6A
	Bus Interface Unit (BIU)	RS485	DD25-24V

References