Sign Up For Our Email Updates

Add to favorites  Print this page  Send to a friend  Download PDF of this page 
Find a Representative

Viper-ST® Solid Dielectric, Triple Option Reclosers

Viper®-ST Solid Dielectric, Triple Option Reclosers 



G&W's Viper-ST solid dielectric, triple option recloser combines the time proven reliability of electronically controlled, vacuum fault interrupters with the maintenance-free benefits of a solid dielectric insulated device. The triple option feature offers ultimate user flexibility by permitting three distinct mechanical operation modes, either 1-phase trip / 1-phase lockout, 1-phase trip / 3-phase lockout or 3-phase trip / 3-phase lockout. The Viper -ST provides overcurrent protection for systems through 38kV maximum, 800A continuous current and 12.5kA symmetrical interrupting with 16kA symmetrical interrupting up to 27kV.



  • Reliable Performance - Viper-ST reclosers utilize G&W’s time-proven EPOX polymer system to fully encapsulate the vacuum interrupters. This system provides excellent insulation properties while providing fully shielded, void-free construction.
  • Ease of Operation -The Viper-ST is compatible with the SEL-651R control
  • Ease of Installation - The Viper-ST is lightweight and compact. Site-ready designs provide all accessories preassembled prior to shipment, significantly reducing installation time.
  • Smart Grid /Lazer Automation - The Viper-ST is automation ready, simplifying conversion for any future automation requirements.
  • Dead-Line Operation - The unique design of the Viper-ST magnetic actuator system provides for local and remote operation of the recloser in the event that the AC source power is lost or interrupted.
  • Voltage & Current Sensing - The Viper-ST recloser has up to six voltage sensors for voltage sensing and multi-ratio current transformers for current sensing.


Introducing Accusense™ Voltage Sensors:

  • G&W’s Accusense™ Voltage Sensors are a metering-class voltage-sensing solution that enables users to collect critical voltage data needed for optimizing grid power delivery and reliability. Accusense voltage-sensing technology eliminates the need for traditional metering class voltage-transformers and are available with the Viper-ST recloser as a site-ready solution.
  • Apply Accusense voltage sensors in high accuracy high-accuracy voltage measurement and power quality applications such as volt-var optimization (VVO), conservation voltage reduction (CVR), end of line/intertie metering.
  • Accusense allows a smaller, lighter, and less expensive solution over instrument transformers which are traditionally used for these applications

Polemount Center Bracket

Polemount Site-Ready Assembly

Preassembly of all auxiliary equipment significantly reduces recloser preparation time for product installation in the field. Includes potential transformers or voltage transformers, arresters, aerial lugs, terminal/junction boxes, wildlife protectors and all associated wiring. Control cables are connectorized on both ends and cut to length for a cleaner installation. User
identification markers can be preapplied to each unit prior to shipment further reducing installation time.

Polemount Cluster Bracket

Polemount Horizontal Insulator Bracket

This configuration is ideal for overhead applications where all three phase conductors are on the same side of the pole or for congested installations with minimal phase spacing.


Substation Mount Recloser

Padmount Reclosers

For applications where space is limited at the substation or where underground feeders require protection, Viper-ST solid dielectric reclosers can provide an ideal solution using a dead-front padmount design. In this configuration, the cable connections can be provided with either a standard IEEE 600A apparatus or 200A deepwell interface for elbow connectors. Separate compartments are provided for accessing the cables and operators. Controls can be mounted directly to the recloser frame or within a separate adjacent enclosure.


Electrical Ratings:
Maximum Design Voltage, kV 
Impulse level (BIL), kV
Continuous & load break current, A
8-hour Overload, A rms
60Hz Withstand, kV rms
  One minute (dry)
  10 second (wet)



Radio Influence Voltage, microvolts 100 @
Interrupting Current, kA rms sym.
Making Current, kA asym. rms
Making Current, kA asym. peak
Short Circuit Current, kA sym., 3 second
Mechanical endurance, operations




The Viper-ST works directly with the popular Schweitzer SEL-651R control. Typical features of the SEL-651R include:

  • Six voltage inputs necessary for loop scheme designs
  • Full line metering capabilities using the voltage inputs from the internal sensors
  • Programming to recognize seasonal loads and shift between three phase and single phase trip/close modes for optimal system efficiency
  • For loop schemes the control can be programmed to act as a recloser “looking” in either direction
  • Minimum trip for phase, ground and sensitive earth faults
  • Capable of up to four shots to lockout
  • Sequence coordination
  • Harmonics up to the 15th for the THD analysis
  • Cold load pickup


A twist lock style connector makes the cable connection between the control and the interrupter control box. AC power provides the normal supply power to the control.


The following options can be supplied:

  • NEMA 2-hole aerial lugs
  • NEMA 4-hole aerial lugs
  • Clamp style aerial lugs (#2- 500 kcmil)
  • Clamp style aerial lugs (250-750 kcmil)
  • 4/0 brass eyebolt ground lug
  • Galvanized polemount center bracket with arrester provisions on the load and source side.
  • Stainless steel polemount center bracket with arrester provisions on the load and source side.
  • Stainless steel polemount side bracket with arrester provisions on the load and source side.
  • Stainless steel substation frame.
  • Polemount site-ready assembly
  • Lightning arresters
  • Dead-front padmounted design with stainless steel enclosure.
  • External 1.0 KVA oil potential transformer (3% accuracy) for 120 VAC supply power with hardware to mount on standard aluminum frame
  • External 0.75 KVA solid dielectric voltage transformer (0.3% accuracy) for 120 VAC supply power with hardware to mount on standard aluminum frame
  • High impact, UV stable wildlife protectors for source and load insulators
  • External CTs for current monitoring
  • Six internal voltage sensors
  • Junction box with all twist lock connections
  • 42 pin interface with additional 52b auxiliary contact (Form C type) and cable-disconnected alarm (SEL-651R only)
  • 3-phase ganged manual trip handle

Drawings (Click Image to Enlarge)



G&W Shanghai  |  MBAF Foundry  |  Survalent Technology  |  G&W Canada  |  Technical or Warranty  |  Terms & Conditions  |  Privacy Policy  |  Sales Home  |  Suppliers

© 2019 Site Map | Site Credits: Ecreativeworks