Eaton STS366UD31 Shunt Trip Safety Switch - UL Listed
Part Number: STS366UD31
Quick Summary
STS366UD31 shunt trip safety switch provides fast, reliable overcurrent protection for motor control centers and switchgear. Engineers often contend with nuisance trips and unplanned downtime when protection devices misinterpret transient faults. UL Listed and cUL Certified protection with NEMA 12 and NEMA 3R enclosures ensure dependable performance in harsh environments. This device supports 600 A service with a 120 Vac coil and accommodates main ratings of 600 Vac / 250 Vdc, enabling seamless integration into existing protection schemes. Designed for industrial protection with strong warranty and service support, it delivers measurable business value by reducing downtime and improving safety across critical electrical systems.
Product Information
Extended Description
STS366UD31 Eaton: Eaton shunt trip safety switch, 600 A, Three-pole, 600 Vac, 250 Vdc, Alarm switch, 120 Vac, 1 NO-1 NC, NEMA 12, NEMA 3R, Non-Fusible, 600 V
Product Name
Eaton shunt trip safety switch
Catalog Number
STS366UD31
UPC
786685829241
Product Length/Depth
12.43 in
Product Height
62.97 in
Product Width
28.29 in
Product Weight
140 lb
Warranty
Eaton Selling Policy 25-000, one (1) year from the date of installation of the Product or eighteen (18) months from the date of shipment of the Product, whichever occurs first.
Certifications
UL Listed cUL Certified
Auxiliary contacts
Alarm switch
Enclosure
NEMA 12, NEMA 3R
Number Of Poles
Three-pole
Type
Shunt trip safety switch
Amperage Rating
600A
Coil voltage
120 Vac
Protection
Non-Fusible
Voltage rating
600 Vac, 250 Vdc
Contact configuration
1 NO-1 NC
Switching Devices Flex Center
Switching Devices Flex Center
Switching Devices Flex Center
Eaton Specification Sheet - STS366UD31
Feature → Business Impact → Application: The STS366UD31 provides a 600 A amperage rating, enabling it to interrup t high-power motor loads in large switchgear and MCC assemblies, reducing fuse changes and preventing extended outages in manufacturing lines. This translates to measurable reliability improvements and lower maintenance costs in plant protection schemes, particularly for heavy inductive loads. Feature → Business Impact → Application: A 120 Vac coil voltage simplifies control wiring and allows straightforward integration with standard control circuits, shortening installation time and lowering wiring errors in new builds or retrofits for process lines or packaging facilities. Feature → Business Impact → Application: The three-pole design with a 600 Vac / 250 Vdc main rating supports versatile protection across AC and DC circuits, delivering consistent tripping performance in demanding environments such as metal fabrication or chemical processing plants. Feature → Business Impact → Application: An auxiliary alarm contact (1 NO-1 NC) provides status signaling to SCADA or maintenance panels, improving remote monitoring and reducing unplanned service visits. Feature → Business Impact → Application: NEMA 12 and NEMA 3R enclosures guard against dust, moisture, and mild corrosion, enabling outdoor or harsh indoor installations in weather-exposed switchgear and outdoor substations. Feature → Business Impact → Application: UL Listed and cUL Certified compliance ensures alignment with safety standards, supporting audits and procurement requirements while minimizing risk during regulatory reviews. Feature → Business Impact → Application: The non-fusible design minimizes coordination complexity and simplifies maintenance planning, reducing total cost of ownership in mission-critical protection schemes. Dimensions and weight (12.43 in depth, 62.97 in height, 28.29 in width, 140 lb) inform enclosure sizing and mounting strategies for retrofit or new installations in existing panels.
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FAQs
STS366UD31 is a three-pole shunt trip switch rated for 600 A with 120 Vac coil voltage, designed to retrofit or replace older safety switches within standard MCCs and switchgear. Its NEMA 12 and NEMA 3R enclosure ratings simplify mounting in dusty, damp, or outdoor environments, while the 12.43 in depth and 28.29 in width fit common panel openings. Ensure control wiring matches 120 Vac coil requirements and verify space for a 140 lb unit during installation.
Key ratings include 600 A amperage, 600 Vac main voltage, 250 Vdc auxiliary DC system compatibility, and a 120 Vac coil voltage. The unit provides 1 NO-1 NC contact configuration for signaling and interlocking, and it is non-fusible, which helps with safer, simpler maintenance and faster reset after trips.
Yes. The device features NEMA 12 and NEMA 3R enclosure ratings, which protect against dust, moisture, and incidental rain or corrosion in outdoor or challenging indoor settings. This makes it appropriate for outdoor switchgear, exposed substations, and industrial plants with variable environmental conditions.
STS366UD31 is UL Listed and cUL Certified, demonstrating conformance to widely recognized safety standards. These certifications support regulatory audits, supplier qualification, and customer procurement requirements, helping ensure safe operation and easier passing of compliance reviews in industrial facilities.
The non-fusible design reduces fuse coordination complexity and provides straightforward reset behavior after trips, lowering maintenance complexity and downtime. The 600 A rating and integrated alarm contact enable proactive monitoring via SCADA or maintenance dashboards, supporting data-driven maintenance and potentially reducing unplanned outages and total cost of ownership.