The Model SSS-120VAC-LL was designed as a Primary Stage protection device for a single 120 VAC line pair. This could be a floating 120 VAC line pair from an isolation transformer or a utility line pair with one side referenced to the Neutral/Ground point.

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  • High-Energy MOV Protection
  • Light weight, high-strength Polycarbonate enclosure
  • Clear cover for easy inspection
  • 100% field repairable
  • All components are UL Listed
  • Operating Temperature: -40 to +70°C


  • High-Energy MOV Primary Stage protection for a floating single phase 120 VAC feeder
  • All-Mode protection including both line-to-line and line-to-ground
  • Equipped with a 3/4" Conduit Offset Nipple for easy mounting to a Service Entrance Panel

Electrical Specifications

120 VAC (Line-to-Line) or (Line-to-Ground) Protection Levels

  • Maximum No Conduction AC Voltage = 140 Vrms
  • Maximum 1mA Conduction Voltage = 198 Vrms
  • Maximum single pulse energy = 600 Joules
  • Maximum single pulse current = 70,000 Amperes
  • Clamping level = 360 Volt peak @ 500 Amperes

Mechanical & Temperature Specifications:

  • Length = 5 in.
  • Width = 5 in.
  • Depth = 4 in.
  • Weight = 1 lb.
  • The unit is equipped with a 3/4" offset nipple making it "installation-ready"
  • Operating Temperature Range: -40 to +70°C


Functional Wiring Diagram:


This unit is designed to protect a single line pair AC Power feeder with a nominal voltage of 120VAC. This is a primary stage differential (Line-to-Line) protector and would be connected at the Breaker / Distribution Panel before the power is distributed throughout the Signal House or Case.

The protected power can be:
  • An isolated floating (no ground connection) AC feeder from an Isolation Transformer
  • A non-isolated (one side grounded) AC feeder

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